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Indian Institute of Science
1.
Manikandan, N.
Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses.
Degree: 2007, Indian Institute of Science
URL: http://hdl.handle.net/2005/528 
► The ability to tune the properties over a wide range of values by changing the additives, composition, etc., has made chalcogenide glassy semiconductors, most interesting…
(more)
▼ The ability to tune the properties over a wide range of values by changing the additives, composition, etc., has made chalcogenide glassy semiconductors, most interesting from both fundamental physics as well as technology point of view. In particular, the occurrence of the two network topological thresholds namely the Rigidity Percolation Threshold (RPT) and the Chemical Threshold (CT) and their influence on various properties of chalcogenide glasses have been of immense interest during the last three decades.
The Rigidity Percolation Threshold (also known as the Stiffness Threshold or Mechanical Threshold) corresponds to the composition at which the material transforms from a floppy polymeric glass to a rigid amorphous solid, whereas at Chemical Threshold the sample tends towards an ordered state. Though the rigidity percolation has been considered for long to occur at a critical threshold defined by the constraint’
s theory, the recent theoretical and experimental investigations have found the RPT to occur over a range of compositions. In systems exhibiting an extended rigidity percolation, two distinct transitions namely from a floppy to an isostatically rigid phase and from an isostatically rigid to a stressed rigid phase are seen.
In the category of chalcogenide glasses, tellurides have been found to exhibit interesting properties including the phenomenon of electrical switching which finds applications in Phase Change Memories (PCM). Studies on various thermal, electrical and photoelectrical properties of glassy tellurides help us in identifying suitable materials for different technological applications.
This thesis deals with Differential Scanning Calorimetric (DSC) & Temperature Modulated Alternating Differential Scanning Calorimetric (ADSC) studies, electrical switching investigations, photoconductivity & photothermal measurements on certain metal doped telluride glasses. The composition dependence of properties such as glass transition & crystallization temperatures, switching voltage, thermal diffusivity, photosensitivity, etc., have been analyzed to obtain information about topological thresholds, thermally reversing window, etc.
The first chapter of thesis provides an overview of properties of amorphous semiconductors, in particular chalcogenide glasses. The local & defect structure, the electronic band structure & electrical properties, electrical switching behavior, etc., are discussed in detail. The theoretical aspects related to the experiments undertaken in this thesis work have also been described.
The instrumentation used for various experiments conducted to measure thermal, electrical, photoelectrical and photothermal properties have been discussed in chapter two.
The chapter three deals with the photocurrent measurements on As40Te60-xInx
(7.5 ≤ x ≤ 16.5) glasses. In these samples, it has been found that the photocurrent increases with illumination, which is understood on the basis of the large dielectric constant and also due to the presence of a large number of positively charged…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Chalcogenide Glasses - Instrumentation; Telluride Glasses - Instrumentation; Amorphous Semiconductors; Chalcogenide Glasses - Properties; Network Topological Thresholds; Rigidity Percolation Threshold (RPT); Chemical Threshold (CT); Altrnating Differential Scanning Calorimetry (ADSC); Chalcogenide Glassy Semiconductors; Phase Change Memories (PCM); Differential Scanning Calorimetry (DSC); Instrumentation
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APA (6th Edition):
Manikandan, N. (2007). Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/528
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Manikandan, N. “Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses.” 2007. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/528.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Manikandan, N. “Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses.” 2007. Web. 19 Nov 2019.
Vancouver:
Manikandan N. Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses. [Internet] [Thesis]. Indian Institute of Science; 2007. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/528.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Manikandan N. Investigations On Topological Thresholds In Metal Doped Ternary Telluride Glasses. [Thesis]. Indian Institute of Science; 2007. Available from: http://hdl.handle.net/2005/528
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
2.
Anbarasu, M.
Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications.
Degree: 2007, Indian Institute of Science
URL: http://hdl.handle.net/2005/617
► The Phase Change Memories (PCM) based on chalcogenide glasses are being considered recently as a possible replacement for conventional Non Volatile Random Access Memories (NVRAM).…
(more)
▼ The Phase Change Memories (PCM) based on chalcogenide glasses are being considered recently as a possible replacement for conventional Non Volatile Random Access Memories (NVRAM). The main advantages of chalcogenide phase change memories are their direct write/overwrite capability, lower voltages of operation, large write/erase cycles, easiness to integrate with logic, etc. The phase change random access memories work on the principle of memory switching exhibited by chalcogenide glasses during which a local structural change (between amorphous and crystalline states) occurs due to an applied electric field.
The development of newer phase change materials for NVRAM applications is based on synthesizing newer glass compositions and investigating their electrical switching characteristics by applying current/voltage pulses of different waveforms. The thermal studies on chalcogenide glasses which provide information about thermal stability, glass forming ability, etc., are also important while selecting a chalcogenide glass for PCM applications.
The present thesis work deals with electrical switching and thermal studies on certain silicon based ternary telluride glasses (As-Te-Si, Ge-Te-Si and Al-Te-Si). The effect of network topological thresholds on the composition dependence of switching voltages and thermal parameters such as glass transition temperature, specific heat capacity, non-reversing enthalpy, etc., of these glasses has been investigated.
The first chapter of the thesis provides an introduction to various properties of chalcogenide glasses, including their applications in phase change memories. The fundamental aspects of amorphous solids such as glass formation, glass transition, etc., are presented. Further, the concepts of rigidity percolation and self organization in glassy networks and the influence of local structural effects on the properties of glassy chalcogenides are discussed. Also, a brief history of evolution of phase change memories is presented.
The second chapter deals with the experimental techniques employed in this thesis work; for sample preparation and for electrical switching studies, Alternating Differential Scanning Calorimetry (ADSC), Raman spectroscopy, NMR spectroscopy, etc.
The third chapter discusses the electrical switching and thermal studies on As30Te70-xSix (2 ≤ x ≤ 22) and As40Te60-xSix (2 ≤ x ≤ 17) glasses. The composition dependence of electrical switching voltage (VT) and thermal parameters such as glass transition temperature (Tg), crystallization temperature (Tc), thermal stability (Tc-Tg), etc., reveals the occurrence of extended rigidity percolation and chemical thresholds in As30Te70-xSix and As40Te60-xSix glasses.
Chapter 4 presents the electrical switching and thermal studies on Ge15Te85-xSix glasses (2 ≤ x ≤ 12). These glasses have been found to exhibit memory type electrical switching. While Ge15Te85-xSix glasses with x ≤ 5 exhibit a normal electrical switching, an unstable behavior is seen in the I-V characteristics of Ge15Te85-xSix glasses with x > 5…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Telluride Glasses - Electrical Properties; Chalcogenide Glasses; Chalcogenide Glasses - Phase Change Memory Applications; Telluride Glasses - Thermal Properties; Glassy Chalcogenides; As-Te-Si Glasses; Ge-Te-Si Glasses; Al-Te-Si Glasses; Phase Change Memory; Raman Scattering; Electrical Switching; SET-RESET Processes; Materials Science
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APA (6th Edition):
Anbarasu, M. (2007). Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/617
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Anbarasu, M. “Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications.” 2007. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/617.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Anbarasu, M. “Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications.” 2007. Web. 19 Nov 2019.
Vancouver:
Anbarasu M. Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications. [Internet] [Thesis]. Indian Institute of Science; 2007. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/617.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Anbarasu M. Electrical Switching And Thermal Studies On Certain Ternary Telluride Glasses With Silicon Additive And Investigations On Their Suitability For Phase Change Memory Applications. [Thesis]. Indian Institute of Science; 2007. Available from: http://hdl.handle.net/2005/617
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
3.
Madhav, Kalaga Venu.
All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications.
Degree: 2007, Indian Institute of Science
URL: http://hdl.handle.net/2005/644
► In this thesis, we explore the four aspects of fiber Bragg grating sensors: mathematical modeling of Fiber Bragg Grating response/spectral characteristics, fabrication using phase mask,…
(more)
▼ In this thesis, we explore the four aspects of fiber Bragg grating sensors: mathematical modeling of Fiber Bragg Grating response/spectral characteristics, fabrication using phase mask, application and interrogation. Applications of fiber Bragg gratings, also known as in-fiber gratings, with emphasis on their sensing capabilities, interrogation of an array of sensors and their performance in structural health monitoring scenario are documented.
First, we study the process of photosensitivity phenomenon in glasses, in particular GeO2:SiO2 glasses. For mathematical modeling we consider the 1-D refractive index profile along the propagation axis of an optical fiber drawn from the preform of such glasses. These 1-D index structures exhibit a bandgap for propagation along the fiber axis. We show how the bandgap is dependent on the two structural parameters: index periodicity and effective refractive index. The mathematical model provides the characteristics of three sensor parameters -resonance wavelength also known as the Bragg wavelength (λB ), filter bandwidth (ΔλB ), and reflectivity (R). We show that the evolution of the index structure in germanosilicate glasses is dependent on the inscription parameters such as exposure time, intensity of the laser used for inscribing, the interference pattern, and coherence of the laser system. In particular, a phase mask is used as the diffffacting element to generate the required interference pattern, that is exposed on the photosensitive fiber. We present a mathematical model of the electromagnetic diffraction pattern behind the phase mask and study the effect of the limited coherence of the writing laser on the interference pattern produced by the diffracting beams from the mask.
Next, we demostrate the sensing capabilities of the fiber Bragg gratings for measuring strain, temperature and magnetic fields. We report linearity of 99.7% and sensitivity of 10.35pm/◦C for the grating temperature sensor. An array of gratings assigned with non-overlapping spectral windows is inscribed in a single fiber and applied for distributed sensing of structural health monitoring of an aircraft’
s composite air-brake panel. The performance of these sensors is compared with the industry standard resistance foil gauges. We report good agreement between the two gauges (FBG and RSG).
In some applications it is more desirable to know the spectral content, rather than the magnitude of perturbation. Fiber Bragg gratings sensors can be used to track events that occur in a very small span of time and contain high frequencies. Such applications demand very high speed wavelength demodulation methods. We present two interrogation techniques: wavelength-shift time-stamping (WSTS) and reflectivity division multiplexing (RDM). WSTS interrogation method employs the multiple threshold-crossing technique to quantize the sensor grating fluctuations and in the process produces the time stamps at every level-cross. The time-stamps are assembled and with the a priori knowledge of the threshold levels, the strain…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Structural Health Monitoring; Optical Devices; Fiber Optics; Fiber Bragg Gratings (FBG); Optical Fibers - Photosensitivity; Fiber Bragg Grating Sensor; Fiber Bragg Grating - Mathematical Modeling; Photonic Bandgap; Fabricated Gratings; FBG Fabrication; Grating; Fiber Sensing; Reflectivity Division Multiplexing; Instrumentation
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APA (6th Edition):
Madhav, K. V. (2007). All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/644
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Madhav, Kalaga Venu. “All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications.” 2007. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/644.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Madhav, Kalaga Venu. “All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications.” 2007. Web. 19 Nov 2019.
Vancouver:
Madhav KV. All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications. [Internet] [Thesis]. Indian Institute of Science; 2007. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/644.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Madhav KV. All-Fiber Sensing Techniques For Structural Health Monitoring And Other Applications. [Thesis]. Indian Institute of Science; 2007. Available from: http://hdl.handle.net/2005/644
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
4.
Pattanayak, Pulok.
Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses.
Degree: 2008, Indian Institute of Science
URL: http://hdl.handle.net/2005/865
► Silver containing chalcogenide glasses have been extensively studied during the last few decades; the main interest in these materials being their electrical conductivity which changes…
(more)
▼ Silver containing chalcogenide glasses have been extensively studied during the last few decades; the main interest in these materials being their electrical conductivity which changes by several orders of magnitude upon silver doping. Glassy chalcogenides doped with silver have applications in optical elements, gratings, micro-lenses, waveguides, bio & chemical sensors, solid electrolytes, batteries, etc.
Chalcohalide glasses have become important in the recent times, from both scientific & technological points of view, due to the interesting properties exhibited by these glasses such as the transparency in the infrared region, the stability against devitrification, solubility of rare earth elements, etc.
In this thesis work, the thermal properties and electrical switching behavior of certain silver and iodine doped chalcogenide glasses have been investigated
The thesis contains five chapters:
Chapter 1:
This chapter is an introduction to the fundamental aspects of amorphous semiconductors with a particular reference to chalcogenide glasses. The advantages and applications of chalcogenide glasses are also described.
Chapter 2:
The methods of preparation and characterization of the glasses investigated are described in this chapter. Also, the details of the experiments undertaken, namely temperature modulated Alternating Differential Scanning Calorimetry (ADSC), electrical switching analysis, Photo-thermal Deflection Spectroscopy (PDS), etc, are outlined.
Chapter 3:
In this chapter, the thermal behavior and electrical switching of silver doped Ge-Se and As-Se chalcogenide glasses are described.
Bulk, melt-quenched Se-rich Ge0.15Se0.85-xAgx glasses have been found to be microscopically phase separated and composed of Ag2Se clusters and GeSe2-Se network. When the silver concentration exceeds 10 atom %, the Ag2Se clusters embedded in the GeSe2-Se network percolate. The signature of this percolation threshold is clearly observed as the sudden appearance of two exothermic crystallization peaks in ADSC runs. Density, molar volume and micro hardness studies also strongly support the view of a percolation transition. The super-ionic conduction observed earlier in these glasses at higher silver proportions, is likely to be connected with the silver phase percolation.
It has been found that Ge0.15Se0.85-xAgx glasses of lower silver concentration (x = 0.07 and 0.08) do not exhibit electrical switching at voltages up to 1100 V. A negative resistance behavior and threshold type electrical switching is seen in Ge0.15Se0.85-xAgx samples with x 0.09. Also, fluctuations are observed in the I-V characteristics of these samples, which have been attributed to the difference in thermal conductivities between the Ag2Se inclusions and the Ge-Se base glass. A sharp drop has been observed in the switching voltage with Ag concentration which is due to the more metallic nature of silver and the presence of Ag+ ions. Further, the saturation in the decrease of VT around x = 0.10, is related to silver phase percolation in these…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Chalcogenide Glasses; Iodine Doping; Silver Doping; Chalcogenide Glasses - Electrical Properties; Chalcogenide Glasses - Thermal Properties; Glassy Chalcogenides; Amorphous Semiconductors; Glassy Semiconductor; AsSeAg Glasses; Materials Science
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APA (6th Edition):
Pattanayak, P. (2008). Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/865
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Pattanayak, Pulok. “Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses.” 2008. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/865.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Pattanayak, Pulok. “Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses.” 2008. Web. 19 Nov 2019.
Vancouver:
Pattanayak P. Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses. [Internet] [Thesis]. Indian Institute of Science; 2008. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/865.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Pattanayak P. Thermal And Electrical Properties Of Silver And Iodine Doped Chalcogenide Glasses. [Thesis]. Indian Institute of Science; 2008. Available from: http://hdl.handle.net/2005/865
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
5.
Yamdagni, Sumeet.
Fiber Bragg Grating Interrogation Systems.
Degree: 2009, Indian Institute of Science
URL: http://hdl.handle.net/2005/925
► This thesis work deals with the development of three different categories of interrogation techniques for Fiber Bragg Grating based sensor networks. Such networks are used…
(more)
▼ This thesis work deals with the development of three different categories of interrogation techniques for Fiber Bragg Grating based sensor networks. Such networks are used for structural health monitoring and other applications.
A bulk grating based interrogation system is described first, which includes an optical source, switch, circulator, embedded controller, and software. The center wavelength determination technique employed is detailed and is shown to be highly accurate from test data. The comparison with resistance strain gauges is presented which shows that the system developed provides an accurate strain reconstruction. The system is also compared with a commercial optical spectrum analyzer and is found to exhibit good accuracy and fidelity. The system has been field tested on an aircraft structure with 14 sensors spread over 4 channels. Strain data reconstruction from these tests is shown to accurately reproduce the loading conditions.
A second system developed is based on the matched filter technique using a mechanical fiber stretcher; the details of this system are presented with a mathematical treatment of the technique. The design of the fiber stretcher is also described. This design is regarded to be novel since it tries to provide large interrogation bandwidths using a parallel topology. The results of tests have shown good resolution and comparative tests with resistance strain gauges have shown accurate reproduction of strain.
Finally, an interrogation system based on a wavelength tunable source is presented. This system is a precursor to a time division multiplexed interrogation system, which has also been described. Three laser configurations have been set up and characterized. The laser sweep tests have been performed on two configurations and a sensor grating reconstruction test has also been carried out.
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Fiber Bragg Gratings; Sensor Systems; Filters (Electronic); Structural Health Monitoring; Bulk Grating Interrogation System; Flexure Based Interrogation System; Tunable Laser Interrogation System; FBG Fabrication; Sensor Networks; Wireless Sensors; Instrumentation
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APA ·
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APA (6th Edition):
Yamdagni, S. (2009). Fiber Bragg Grating Interrogation Systems. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/925
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Yamdagni, Sumeet. “Fiber Bragg Grating Interrogation Systems.” 2009. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/925.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Yamdagni, Sumeet. “Fiber Bragg Grating Interrogation Systems.” 2009. Web. 19 Nov 2019.
Vancouver:
Yamdagni S. Fiber Bragg Grating Interrogation Systems. [Internet] [Thesis]. Indian Institute of Science; 2009. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/925.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Yamdagni S. Fiber Bragg Grating Interrogation Systems. [Thesis]. Indian Institute of Science; 2009. Available from: http://hdl.handle.net/2005/925
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
6.
Mahesh, Kondiparthi.
Novel Methods To Interrogate Fiber Bragg Grating Sensors.
Degree: 2010, Indian Institute of Science
URL: http://hdl.handle.net/2005/1926
► A novel detection technique to estimate the amount of chirp in fiber Bragg gratings (FBGs) is proposed. This method is based on the fact that…
(more)
▼ A novel detection technique to estimate the amount of chirp in fiber Bragg gratings (FBGs) is proposed. This method is based on the fact that reflectivity at central wavelength of FBG reflection changes with strain/temperature gradient (linear chirp) applied to the same. Transfer matrix approach was used to vary different grating parameters (length, strength and apodization) to optimize variation of reflectivity with linear chirp. Analysis is done for different sets of ‘FBG length-refractive index strength’ combinations for which reflectivity vary linearly with linear chirp over a decent measurement range. This work acts as a guideline to choose appropriate grating parameters in designing sensing apparatus based on change in reflectivity at central wavelength of FBG reflection.
A novel high sensitive FBG strain sensing technique using lasers locked to relative frequency reference is proposed and analyzed theoretically. Static strain on FBG independent of temperature can be measured by locking frequency of diode laser to the mid reflection frequency of matched reference FBG, which responds to temperature similar to that of the sensor FBG, but is immune to strain applied to the same. Difference between light intensities reflected from the sensor and reference FBGs (proportional to the difference between respective pass band gains at the diode laser frequency) is not only proportional to the relative strain between the sensor and reference FBGs but also independent of servo residual frequency errors. Usage of relative frequency reference avoids all complexities involved in the usage of absolute frequency reference, hence, making the system simple and economical. Theoretical limit for dynamic and static strain sensitivities
considering all major noise contributions are respectively of the order of 25 pε/ Hz and
1.2nε /
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Bragg's Grating Sensor; Fiber Bragg Grating; FBG Reflection Spectra; Fiber Optics; Fiber Bragg Gratings (FBGs); Instrumentation
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APA ·
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APA (6th Edition):
Mahesh, K. (2010). Novel Methods To Interrogate Fiber Bragg Grating Sensors. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/1926
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Mahesh, Kondiparthi. “Novel Methods To Interrogate Fiber Bragg Grating Sensors.” 2010. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/1926.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mahesh, Kondiparthi. “Novel Methods To Interrogate Fiber Bragg Grating Sensors.” 2010. Web. 19 Nov 2019.
Vancouver:
Mahesh K. Novel Methods To Interrogate Fiber Bragg Grating Sensors. [Internet] [Thesis]. Indian Institute of Science; 2010. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/1926.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mahesh K. Novel Methods To Interrogate Fiber Bragg Grating Sensors. [Thesis]. Indian Institute of Science; 2010. Available from: http://hdl.handle.net/2005/1926
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
7.
Prashanth, S B Bhanu.
Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides.
Degree: 2008, Indian Institute of Science
URL: http://hdl.handle.net/2005/735
► The absence of long-range order in glassy chalcogenides provides the convenience of changing the elemental ratios and hence the properties over a wide range. The…
(more)
▼ The absence of long-range order in glassy chalcogenides provides the convenience of changing the elemental ratios and hence the properties over a wide range. The interesting properties exhibited by chalcogenide glasses make them suitable materials for Phase Change Memories (PCM) and other applications such as infrared optical devices, photo-receptors, sensors, waveguides, etc.
One of the most remarkable properties of chalcogenides is their electrical switching behavior. Reversible (threshold type) or irreversible (memory type) switching from a high resistance OFF state to a low resistance ON state in glassy chalcogenides occurs at a critical voltage called the threshold/switching voltage (VT). Investigations on the switching behavior and its composition dependence throw light on the local structural effects of amorphous chalcogenide semiconductors and also help us in identifying suitable samples for PCM applications.
Thermal analysis by Differential Scanning Calorimetry (DSC) has been extensively used in glass
science, particularly for measurements of thermal parameters such as enthalpy of relaxation, specific heat change, etc., near glass transition. Quite recently, the conventional DSC has been sophisticated by employing a composite temperature profile for heating, resulting in the Temperature Modulated DSC (TMDSC) or Alternating DSC (ADSC). Measurements made using ADSC reveal thermal details with enhanced accuracy and resolution, and this has lead to a better understanding of the nature of glass transition. The thermal parameters obtained using DSC/ADSC are also vital for understanding the electrical switching behavior of glassy chalcogenides.
The motivation of this thesis was twofold: The first was to develop a novel, high voltage programmable power supply for electrical switching analysis of samples exhibiting high VT, and second to investigate the thermal and electrical switching behavior of certain Se-Te based glasses with Ge and Sb additives.
The thesis contains seven chapters:
Chapter 1:
This chapter provides an overview of amorphous semiconductors (a-SC) with an emphasis on preparation and properties of glassy chalcogenides. The various structural models and topological thresholds of a-SC are discussed with relations to the glass forming ability of materials. The electronic band models and defect states are also dealt with. The essentials of electrical switching behavior of chalcogenides are discussed suggesting the electronic nature of switching and the role of thermal properties on switching.
Chapter 2:
The second chapter essentially deals with theory and practice of the experimental techniques adopted in the thesis work. The details of the melt-quenching method of synthesizing glassy samples are provided. Considering the importance, the theory of thermal analysis by DSC & ADSC, are discussed in detail, highlighting the advantages of the latter method adopted in the thesis work. The instrumentation and electronics, developed and used for electrical switching analysis are also introduced at a…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Glasses - Electric Switching Properties; Glasses - Electric Properties - Instrumentation; Glassy Chalcogenides; Glasses - Thermal Properties; Amorphous Semiconductors; Glass Forming Ability (GFA); High Voltage Electrical Switching Analyzer; GexSe35-xTe65 Glasses; Se-Te Glasses; Applied Physics
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APA (6th Edition):
Prashanth, S. B. B. (2008). Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/735
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Prashanth, S B Bhanu. “Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides.” 2008. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/735.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Prashanth, S B Bhanu. “Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides.” 2008. Web. 19 Nov 2019.
Vancouver:
Prashanth SBB. Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides. [Internet] [Thesis]. Indian Institute of Science; 2008. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/735.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Prashanth SBB. Development Of Instrumentation For Electrical Switching Studies And Investigations On Switching And Thermal Behavior Of Certain Glassy Chalcogenides. [Thesis]. Indian Institute of Science; 2008. Available from: http://hdl.handle.net/2005/735
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
8.
Mahesh, Kondiparthi.
Novel Methods To Interrogate Fiber Bragg Grating Sensors.
Degree: 2010, Indian Institute of Science
URL: http://etd.iisc.ernet.in/handle/2005/1926
;
http://etd.ncsi.iisc.ernet.in/abstracts/2497/G24685-Abs.pdf
► A novel detection technique to estimate the amount of chirp in fiber Bragg gratings (FBGs) is proposed. This method is based on the fact that…
(more)
▼ A novel detection technique to estimate the amount of chirp in fiber Bragg gratings (FBGs) is proposed. This method is based on the fact that reflectivity at central wavelength of FBG reflection changes with strain/temperature gradient (linear chirp) applied to the same. Transfer matrix approach was used to vary different grating parameters (length, strength and apodization) to optimize variation of reflectivity with linear chirp. Analysis is done for different sets of ‘FBG length-refractive index strength’ combinations for which reflectivity vary linearly with linear chirp over a decent measurement range. This work acts as a guideline to choose appropriate grating parameters in designing sensing apparatus based on change in reflectivity at central wavelength of FBG reflection.
A novel high sensitive FBG strain sensing technique using lasers locked to relative frequency reference is proposed and analyzed theoretically. Static strain on FBG independent of temperature can be measured by locking frequency of diode laser to the mid reflection frequency of matched reference FBG, which responds to temperature similar to that of the sensor FBG, but is immune to strain applied to the same. Difference between light intensities reflected from the sensor and reference FBGs (proportional to the difference between respective pass band gains at the diode laser frequency) is not only proportional to the relative strain between the sensor and reference FBGs but also independent of servo residual frequency errors. Usage of relative frequency reference avoids all complexities involved in the usage of absolute frequency reference, hence, making the system simple and economical. Theoretical limit for dynamic and static strain sensitivities
considering all major noise contributions are respectively of the order of 25 pε/ Hz and
1.2nε /
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Bragg's Grating Sensor; Fiber Bragg Grating; FBG Reflection Spectra; Fiber Optics; Fiber Bragg Gratings (FBGs); Instrumentation
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APA ·
Chicago ·
MLA ·
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CSE |
Export
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APA (6th Edition):
Mahesh, K. (2010). Novel Methods To Interrogate Fiber Bragg Grating Sensors. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/1926 ; http://etd.ncsi.iisc.ernet.in/abstracts/2497/G24685-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Mahesh, Kondiparthi. “Novel Methods To Interrogate Fiber Bragg Grating Sensors.” 2010. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/handle/2005/1926 ; http://etd.ncsi.iisc.ernet.in/abstracts/2497/G24685-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mahesh, Kondiparthi. “Novel Methods To Interrogate Fiber Bragg Grating Sensors.” 2010. Web. 19 Nov 2019.
Vancouver:
Mahesh K. Novel Methods To Interrogate Fiber Bragg Grating Sensors. [Internet] [Thesis]. Indian Institute of Science; 2010. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/handle/2005/1926 ; http://etd.ncsi.iisc.ernet.in/abstracts/2497/G24685-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mahesh K. Novel Methods To Interrogate Fiber Bragg Grating Sensors. [Thesis]. Indian Institute of Science; 2010. Available from: http://etd.iisc.ernet.in/handle/2005/1926 ; http://etd.ncsi.iisc.ernet.in/abstracts/2497/G24685-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
9.
Guru Prasad, A S.
Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.
Degree: 2012, Indian Institute of Science
URL: http://etd.iisc.ernet.in/handle/2005/2507
;
http://etd.ncsi.iisc.ernet.in/abstracts/3248/G25522-Abs.pdf
► Sensors have become essential elements in human life for safe and comfortable existence in the ever demanding world. Various technologies over decades have contributed in…
(more)
▼ Sensors have become essential elements in human life for safe and comfortable existence in the ever demanding world. Various technologies over decades have contributed in their own way fulfilling innumerable sensing requirements. The discovery of optical sensor technologies has revolutionized the sensing field due to their inherent advantages. Among the large number of fiber optic sensor technologies, FBG based sensors have become widely known and popular within and outside the photonics community and has seen a prominent rise in their utilization.
This thesis explores the use of FBG sensors for a wide range of applications scanning across a variety of engineering and medical applications, in the areas of civil engineering, biomechanical engineering, aerospace engineering, geoengineering, etc. It also deals with newer methods of packaging FBG sensors for the measurement of specific engineering parameters like strain, temperature, pressure, displacement and vibration.
In the field of civil engineering, FBG sensors are employed for strain sensing on a prism and furthermore tested on a full size brick wallet. During this study, emphasis is made on substituting traditional sensors by specially packaged FBG sensors with the intent of either enhancing the sensing system’
s performance or in merging/uniting the inherent advantages of FBG sensors.
In the area of biomechanics, a novel sensor methodology using FBG sensors, for measuring surface strains generated on the skin of the calf muscle during various leg exercises is proposed. This methodology is used to address one of the most critical and life threatening issues in long distance air travel, namely the Deep Vein Thrombosis. Further, a FBG sensor based plantar sensing plate, is designed and developed, to measure plantar strain distribution in foot and also to analyze the postural stability.
In the field of aerospace engineering, FBG sensors are used for addressing two of the most vital issues; Structural Health Monitoring (SHM) and direct measurement of pressure and temperature on the surface of an aircraft under hypersonic wind flow. Carbon Fiber Composite coupon level testing is carried out to obtain a generic strain calibration factor for the FBG sensor. Further, FBG sensors are exploited for the direct measurement of absolute temperature and pressure on the leeward surface of blunt cone at hypersonic wind speeds.
In the domain of geoengineering, the feasibility studies have been undertaken to use a FBG as a seismic sensor and as a bore-well characterizing sensor. A novel FBG seismic sensor package is developed using a single FBG sensor to pick up the seismic waves propagating through the ground generated from earthquakes and ground tremors. Further, FBG sensors are used for measurement of temperature profiles in a bore-well to delineate and characterize the behavior of fractures during seasonal climatic changes. To summarize, the present thesis demonstrates a comprehensive experimental study which bring out the utility of FBG sensors in a variety of…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Fiber Bragg Grating Sensors; Fiber Bragg Grating Sensor Packaging; Fiber Optic Sensors; Fiber Bragg Gratings; FBG Sensor; FBG Sensing Plate; FBG Seismic Sensor; Fiber Bragg Grating Sensor; Instrumentation
Record Details
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Record Details
Similar Records
Cite
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Guru Prasad, A. S. (2012). Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/2507 ; http://etd.ncsi.iisc.ernet.in/abstracts/3248/G25522-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Guru Prasad, A S. “Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.” 2012. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/handle/2005/2507 ; http://etd.ncsi.iisc.ernet.in/abstracts/3248/G25522-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Guru Prasad, A S. “Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.” 2012. Web. 19 Nov 2019.
Vancouver:
Guru Prasad AS. Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. [Internet] [Thesis]. Indian Institute of Science; 2012. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/handle/2005/2507 ; http://etd.ncsi.iisc.ernet.in/abstracts/3248/G25522-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Guru Prasad AS. Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. [Thesis]. Indian Institute of Science; 2012. Available from: http://etd.iisc.ernet.in/handle/2005/2507 ; http://etd.ncsi.iisc.ernet.in/abstracts/3248/G25522-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
10.
Guru Prasad, A S.
Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.
Degree: 2012, Indian Institute of Science
URL: http://hdl.handle.net/2005/2507
► Sensors have become essential elements in human life for safe and comfortable existence in the ever demanding world. Various technologies over decades have contributed in…
(more)
▼ Sensors have become essential elements in human life for safe and comfortable existence in the ever demanding world. Various technologies over decades have contributed in their own way fulfilling innumerable sensing requirements. The discovery of optical sensor technologies has revolutionized the sensing field due to their inherent advantages. Among the large number of fiber optic sensor technologies, FBG based sensors have become widely known and popular within and outside the photonics community and has seen a prominent rise in their utilization.
This thesis explores the use of FBG sensors for a wide range of applications scanning across a variety of engineering and medical applications, in the areas of civil engineering, biomechanical engineering, aerospace engineering, geoengineering, etc. It also deals with newer methods of packaging FBG sensors for the measurement of specific engineering parameters like strain, temperature, pressure, displacement and vibration.
In the field of civil engineering, FBG sensors are employed for strain sensing on a prism and furthermore tested on a full size brick wallet. During this study, emphasis is made on substituting traditional sensors by specially packaged FBG sensors with the intent of either enhancing the sensing system’
s performance or in merging/uniting the inherent advantages of FBG sensors.
In the area of biomechanics, a novel sensor methodology using FBG sensors, for measuring surface strains generated on the skin of the calf muscle during various leg exercises is proposed. This methodology is used to address one of the most critical and life threatening issues in long distance air travel, namely the Deep Vein Thrombosis. Further, a FBG sensor based plantar sensing plate, is designed and developed, to measure plantar strain distribution in foot and also to analyze the postural stability.
In the field of aerospace engineering, FBG sensors are used for addressing two of the most vital issues; Structural Health Monitoring (SHM) and direct measurement of pressure and temperature on the surface of an aircraft under hypersonic wind flow. Carbon Fiber Composite coupon level testing is carried out to obtain a generic strain calibration factor for the FBG sensor. Further, FBG sensors are exploited for the direct measurement of absolute temperature and pressure on the leeward surface of blunt cone at hypersonic wind speeds.
In the domain of geoengineering, the feasibility studies have been undertaken to use a FBG as a seismic sensor and as a bore-well characterizing sensor. A novel FBG seismic sensor package is developed using a single FBG sensor to pick up the seismic waves propagating through the ground generated from earthquakes and ground tremors. Further, FBG sensors are used for measurement of temperature profiles in a bore-well to delineate and characterize the behavior of fractures during seasonal climatic changes. To summarize, the present thesis demonstrates a comprehensive experimental study which bring out the utility of FBG sensors in a variety of…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Fiber Bragg Grating Sensors; Fiber Bragg Grating Sensor Packaging; Fiber Optic Sensors; Fiber Bragg Gratings; FBG Sensor; FBG Sensing Plate; FBG Seismic Sensor; Fiber Bragg Grating Sensor; Instrumentation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Guru Prasad, A. S. (2012). Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2507
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Guru Prasad, A S. “Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.” 2012. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/2507.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Guru Prasad, A S. “Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields.” 2012. Web. 19 Nov 2019.
Vancouver:
Guru Prasad AS. Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. [Internet] [Thesis]. Indian Institute of Science; 2012. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/2507.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Guru Prasad AS. Fiber Bragg Grating Sensors : An Exploration Of Applications In Diverse Fields. [Thesis]. Indian Institute of Science; 2012. Available from: http://hdl.handle.net/2005/2507
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
11.
Sreevidya Varma, G.
Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications.
Degree: 2014, Indian Institute of Science
URL: http://hdl.handle.net/2005/3080
► The Science behind amorphous Chalcogenide materials opened up new technologies in the arena of Phase Change Memories. The Ovonic universal phase change memory is called…
(more)
▼ The
Science behind amorphous Chalcogenide materials opened up new technologies in the arena of Phase Change Memories. The Ovonic universal phase change memory is called universal because it can replace flash memory, DRAM and SRAM. These are not only basic computer memory devices but also are becoming the driving force for the ongoing revolutionary growth of cell phones and other mobile devices, which are in desperate need of memory providing higher density, faster speed and lower power consumption.
In this thesis, compositional dependence of various properties of different chalcogenide glasses are investigated, to explore the possibility of their application in Phase Change Memories. Efforts are also made to understand the effect of rigidity and extended rigidity transition on the composition dependence of properties investigated. This thesis comprises of 9 chapters; a brief summary is given below.
Chapter 1 deals with fundamental aspects of amorphous semiconductors with a particular reference to chalcogenide glasses. The advantages and applications of chalcogenide glasses are also described.
Chapter 2 outlines preparation and characterization of the glasses investigated. The sample preparation and various experimental setup used in the present thesis work like Raman Scattering, Nanoindentation, Alternating Differential Scanning Calorimetry (ADSC), Photo-thermal Deflection Spectroscopy (PDS), Electrical Switching are summarized here.
Chapter 3 deals with Micro-Raman studies in Ge15Te85-x Inx Glasses. Micro-Raman studies reveal that as-quenched Ge15Te85-xInx samples exhibit two prominent peaks, at 123 and 155 cm-1. In thermally annealed samples, the peaks at 120 cm-1 and 140 cm-1, which are due to crystalline Te, emerge as the strongest peaks. The Raman spectra of polished samples are similar to those of annealed samples, with strong peaks at 123 cm-1 and 141 cm-1. The spectra of lightly polished samples outside the thermally reversing window resemble those of thermally annealed samples; however, the spectra of glasses with compositions in the thermally reversing window resemble those of as-quenched samples. This observation confirms the earlier idea that compositions in the thermally reversing window are non-ageing and are more stable.
Chapter 4 explains nanoindentation studies undertaken on Ge15Te85-xInx glasse (1 ≤ x ≤ 11). Nanoindentation studies on Ge15Te85-xInx glasses indicate that the hardness and elastic modulus of these glasses increase with indium concentration. While a pronounced plateau is seen in the elastic modulus in the composition range 3 ≤ x ≤ 7, the hardness exhibits a change in slope at compositions x = 3 and x = 7. Also, the density exhibits a broad maximum in this composition range. The observed changes in the mechanical properties and density are clearly associated with the thermally reversing window in Ge15Te85-xInx glasses in the composition range 3 ≤ x ≤ 7. In addition, a local minimum is seen in density and hardness around x = 9, the chemical threshold of the system.
Chapter 5…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Chalcogenide Glasses; Germanium-Tellurium Glasses; Phase Change Memory; Chalcogenide Phase Change Memory; Indium Germanium-Tellurium Glasses; Silver Germanium-Tellurium Glasses; Amorphous Semiconductors; Ge-Te Indium Glasses; Ge-Te-In Glasses; Ge-Te Glasses; Ge15Te85-xInx Glasses; Ge15Te80-xIn5Agx Glasses; Materials Science
Record Details
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Share »
Record Details
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❌
APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sreevidya Varma, G. (2014). Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/3080
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Sreevidya Varma, G. “Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications.” 2014. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/3080.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Sreevidya Varma, G. “Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications.” 2014. Web. 19 Nov 2019.
Vancouver:
Sreevidya Varma G. Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications. [Internet] [Thesis]. Indian Institute of Science; 2014. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/3080.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Sreevidya Varma G. Mechanical, Structural, Thermal and Electrical Studies on Indium and Silver Doped Ge-Te Glasses having Possible PCM Applications. [Thesis]. Indian Institute of Science; 2014. Available from: http://hdl.handle.net/2005/3080
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
12.
Chethana, K.
Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters.
Degree: 2016, Indian Institute of Science
URL: http://hdl.handle.net/2005/3041
► Several sensor technologies have been developed and experimented over the last few decades to cater various needs of medical diagnostics. Among these, fiber optic sensors,…
(more)
▼ Several sensor technologies have been developed and experimented over the last few decades to cater various needs of medical diagnostics. Among these, fiber optic sensors, in particular, Fiber Bragg Grating (FBG) based sensors have attracted considerable attention due to their inherent advantages such electrical passiveness, immunity to Electro Magnetic Interference (EMI), chemical inertness, etc. The present research work focuses on design, development and validation of FBG sensor based devices for measurement of certain healthcare parameters in the context of foot function/gait cycle, cardiac and breathing activity, nostril dominance, hand grip/wrist angle force function, etc. The experimental work presented here emphasizes on the effectiveness and competitiveness of the FBG devices developed, in comparison with standard tools such as Accelerometer, Load cell, Electronic Stethoscope, Electromyogram and Dynamometer.
In the field of human balance, stability and geriatrics, two independent FBG devices namely, Fiber Bragg Grating based Stability Assessment Device (FBGSAD) and Optical Sensor Ground Reaction Force measurement Platform (OSGRFP) have been designed, developed and experimented for postural stability assessment and gait analysis respectively. The result of these studies have significant implications in understanding of the mechanism of plantar strain distribution, identifying issues in gait cycles, detecting foot function discrepancies, identifying individuals who are susceptible to falls and to qualify subjects for balance and stability.
In the field of ergonomic assessment, Fiber Braggs Grating based Hand Grip Device (FBGHGD) is designed and developed for the measurement of hand grip force which helps in the understanding of several important biomechanical aspects such as neuromuscular system function, overall upper-limb strength, vertebral fracture, skeletal muscle function, prediction of disability, incapacity, mortality and bone mass density (forearm, skeletal sites, spine, hip etc.). Further as an extension of this work, the FBGHGD is used for measurement of force generated by the wrist in different positions of the flexion and extension which relates to the wrist muscle activity and its enactment.
In the field of cardiac activity monitoring, a novel, in-vivo, non-invasive and portable device named Fiber Bragg Grating based Heart Beat Device (FBGHBD) is developed for the simultaneous measurement of respiratory and cardiac activities. The work involves designing FBGHBD, validating its performance against traditional diagnostic systems like electronic stethoscope, exploration of its clinical relevance and the usage of FBGHBD in studies involving normal persons and patients with myocardial infarction. The unique design of FBGHBD provides critical information such as nascent morphology of cardiac and breathing activity, heart rate variability, heart beat rhythm, etc., which can assist in early clinical diagnosis of many conditions associated to heart and lung malfunctioning. Further, the scope of this…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Fiber Bragg Grating Sensors; Electromagnetic Interference; Fiber Bragg Grating Stability Assessment Device (FBGSAD); Optical Sensor Ground Reaction Force Measurement Platform (OSGRFP); Fiber Bragg Grating Hand Grip Device (FBGHGD); Fiber Bragg Grating Heart Beat Device (FBGHBD); Nostril Pressure and Temperature Device (NPTD); Healthcare Monitoring; Biomedical Sensors; Fiber Bragg Grating Sensor Devices; FBG Sensor; Fiber Bragg Grating Sensing Plate; Fiber Bragg Grating Devices; Instrumentation
Record Details
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Share »
Record Details
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Cite
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Chethana, K. (2016). Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/3041
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Chethana, K. “Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters.” 2016. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/3041.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Chethana, K. “Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters.” 2016. Web. 19 Nov 2019.
Vancouver:
Chethana K. Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters. [Internet] [Thesis]. Indian Institute of Science; 2016. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/3041.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Chethana K. Design, Development and Validation of Fiber Bragg Grating Sensor Based Devices for Detecting Certain Healthcare Parameters. [Thesis]. Indian Institute of Science; 2016. Available from: http://hdl.handle.net/2005/3041
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
13.
Shikha, *.
Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain.
Degree: 2016, Indian Institute of Science
URL: http://etd.iisc.ernet.in/2005/3816
;
http://etd.iisc.ernet.in/abstracts/4687/G28339-Abs.pdf
► Efficient and accurate sensing of various parameters is needed for numerous applications. In this regard, different categories of sensors play a significant role and different…
(more)
▼ Efficient and accurate sensing of various parameters is needed for numerous applications. In this regard, different categories of sensors play a significant role and different applications require diverse sensing mechanisms owing to the operating conditions and field constraints. Among the several sensor methodologies available, optical fiber sensors have found significant attention, because of their advantages such as negligible foot print, small mass, immunity to Electromagnetic Interference, etc.
In the category of optical fiber sensors, Fiber Bragg Grating (FBG) sensors have found importance in many fields such as health monitoring of civil structures, environmental monitoring involving gas & humidity sensing, monitoring parameters like pressure, tilt, displacement, etc. In the recent times, FBGs have found applications in biomedical, biomechanical and biosensing fields.
A FBG is a periodic change of the refractive index of the core of a single mode optical fiber along its longitudinal axis. The periodic modulation in the index of refraction is obtained by exposing a photosensitive germanium-doped silica fiber to an intense UV laser beam. FBGs, in the basic form, can sense strain and temperature. However, in recent years, several newer sensing applications of FBGs have been demonstrated. Some of the main features of the FBG sensor which qualify them for diverse sensing applications are high sensitivity, large operational bandwidth, multiplexing & multi modal sensing capability, etc.
In this thesis work, FBG sensor based devices have been developed for newer applications in bio-medical fields for the measurement of force, flow and temperature.
Particularly, novel transduction methodologies have been proposed, in order to convert the measurand parameter into a secondary parameter that can be sensed by the FBG sensor.
The evaluation of the force required for a spinal needle to penetrate various tissue layers from skin to the epidural space is vital. In this work, a novel technique for dynamic monitoring of force experienced by a spinal needle during lumbar puncture using Fiber Bragg Grating (FBG) sensor has been developed. The Fiber Bragg Grating Force Device (FBGFD) developed, measures the force on the spinal needle due to varied resistance offered by different tissue layers during its traversal.
The effect of gauge of the spinal needle used for the lumbar puncture procedure affects the force required for its insertion into the tissue. The FBGFD developed, has been further utilized for a comparative study of the force required for lumbar puncture of various tissue layers with spinal needle of different gauges. The results obtained may serve as a guideline for selection of suitable gauge spinal needle during lumbar puncture minimizing post puncture side effects on patients.
The pulmonary function test carried out using a spirometer, provides vital information about the functional status of the respiratory system of the subject. A Fiber Bragg Grating Spirometer (FBGS) has been developed which has the ability…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Fiber Bragg Grating; Fiber Bragg Grating - Biomedical Applications; FBG Fabrication; Bragg Gratings - Internal Inscription; Interferometric Fabrication Technique; Phase Mask Technique; Fiber Bragg Grating Force Device (FBGFD); Fiber Bragg Grating Sensor; FBG Force Device; Pulmonary Function Tests (PFTs); Lumbar Puncture; Instrumentation
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APA (6th Edition):
Shikha, *. (2016). Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/2005/3816 ; http://etd.iisc.ernet.in/abstracts/4687/G28339-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Shikha, *. “Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain.” 2016. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/2005/3816 ; http://etd.iisc.ernet.in/abstracts/4687/G28339-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Shikha, *. “Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain.” 2016. Web. 19 Nov 2019.
Vancouver:
Shikha *. Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain. [Internet] [Thesis]. Indian Institute of Science; 2016. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/2005/3816 ; http://etd.iisc.ernet.in/abstracts/4687/G28339-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Shikha *. Development of Fiber Bragg Grating Sensor Based Devices for Force, Flow and Temperature Measurement for Emerging Applications in Biomedical Domain. [Thesis]. Indian Institute of Science; 2016. Available from: http://etd.iisc.ernet.in/2005/3816 ; http://etd.iisc.ernet.in/abstracts/4687/G28339-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
14.
Sabapathy, Tamilarasan.
Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications.
Degree: 2013, Indian Institute of Science
URL: http://hdl.handle.net/2005/2845
► Chalcogenide glasses are highly nonlinear optical materials which can be used for fabricating active and passive photonic devices. This thesis work deals with the fabrication…
(more)
▼ Chalcogenide glasses are highly nonlinear optical materials which can be used for fabricating active and passive photonic devices. This thesis work deals with the fabrication of buried, three dimensional, channel waveguides in chalcogenide glasses, using ultrafast laser inscription technique.
The femtosecond laser pulses are focused into rare earth ions doped and undoped chalcogenide glasses, few hundred microns below from the surface to modify the physical properties such as refractive index, density, etc. These changes are made use in the fabrication of active and passive photonic waveguides which have applications in integrated optics.
The first chapter provides an introduction to the fundamental aspects of femtosecond laser inscription, laser interaction with matter and chalcogenide glasses for photonic applications. The advantages and applications of chalcogenide glasses are also described. Motivation and overview of the present thesis work have been discussed at the end.
The methods of chalcogenide glass preparation, waveguide fabrication and characterization of the glasses investigated are described in the second chapter. Also, the details of the experiments undertaken, namely, loss (passive insertion loss) and gain measurements (active) and nanoindentation studies are outlined.
Chapter three presents a study on the effect of net fluence on waveguide formation. A heat diffusion model has been used to solve the waveguide cross-section. The waveguide formation in GeGaS chalcogenide glasses using the ultrafast laser, has been analyzed in the light of a finite element thermal diffusion model. The relation between the net fluence and waveguide cross section diameter has been verified using the experimentally measured properties and theoretically predicted values.
Chapter four presents a study on waveguide fabrication on Er doped Chalcogenide glass. The active and passive characterization is done and the optimal waveguide fabrication parameters are given, along with gain properties for Er doped GeGaS glass. A C-band waveguide amplifier has been demonstrated on Chalcogenide glasses using ultrafast laser inscription technique.
A study on the mechanical properties of the waveguide, undertaken using the nanoindentation technique, is presented in the fifth chapter. This work brings out the close relation between the change in mechanical properties such as elastic modulus and hardness of the material under the irradiation of ultrafast laser after the waveguide formation. Also, a threshold value of the modulus and hardness for characterizing the modes of the waveguide is suggested.
Finally, the chapter six provides a summary of work undertaken and also discusses the future work to be carried out.
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Chalcogenide Glasses; Photonic Devices; Optical Waveguides; Chalcogenide Glass Waveguide Amplifiers; Ultrafast Laser Inscription; Chalcogenide Glass Waveguides; Photonic Waveguides; Femtosecond Laser Inscription; Ultrafast Laser Inscribed Optical Waveguides; Ultrafast Laser Inscribed Chalcogenide Glasses; Photonic Integrated Circuits; Waveguide Fabrication; Chalcogenide Glass Preparation; Ultrafast Laser Inscription Technique; Erbium Doped Optical Amplifier (EDFA); Er-doped Chalcogenide Glass; Applied Physics
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APA (6th Edition):
Sabapathy, T. (2013). Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2845
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Sabapathy, Tamilarasan. “Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications.” 2013. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/2845.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Sabapathy, Tamilarasan. “Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications.” 2013. Web. 19 Nov 2019.
Vancouver:
Sabapathy T. Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications. [Internet] [Thesis]. Indian Institute of Science; 2013. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/2845.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Sabapathy T. Ultrafast Laser Inscribed Waveguides on Chalcogenide Glasses for Photonic Applications. [Thesis]. Indian Institute of Science; 2013. Available from: http://hdl.handle.net/2005/2845
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
15.
Lakshmi, K P.
Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories.
Degree: 2013, Indian Institute of Science
URL: http://etd.iisc.ernet.in/2005/3359
;
http://etd.iisc.ernet.in/abstracts/4227/G25760-Abs.pdf
► Chalcogenide glasses are a class of covalent amorphous semiconductors with interesting properties. The presence of short-range order and the pinned Fermi level are the two…
(more)
▼ Chalcogenide glasses are a class of covalent amorphous semiconductors with interesting properties. The presence of short-range order and the pinned Fermi level are the two important properties that make them suitable for many applications. With flash memory technology reaching the scaling limit as per Moore’
s law, alternate materials and techniques are being researched at for realizing next generation non-volatile memories. Two such possibilities that are being looked at are Phase Change Memory (PCM) and Programmable Metallization Cell (PMC) both of which make use of chalcogenide materials.
This thesis starts with a survey of the work done so far in realizing PCMs in reality. For chalcogenides to be used as a main memory or as a replacement to FLASH technology, the electrical switching parameters like switching voltage, programming current, ON state and OFF state resistances, switching time and optical parameters like band gap are to be considered. A survey on the work done in this regard has revealed that various parameters such as chemical composition of the PC material, nature of additives used to enhance the performance of PCM, topological thresholds (Rigidity Percolation Threshold and Chemical Threshold), device geometry, thickness of the active volume, etc., influence the electrical switching parameters. This has motivated to further investigate the material and experimental parameters that affect switching and also to explore the possibility of multi level switching.
In this thesis work, the feasibility of using two chalcogenide systems namely Si15Te85-xGex and Ge15Te85-xAgx in the form of amorphous thin films for PCM application is explored. In the process, electrical switching experiments have been carried out on thin films belonging to these systems and the results obtained are found to exhibit some interesting anomalies. Further experiments and analysis have been carried out to understand these anomalies. Finally, the dynamics of electrical switching has been investigated and presented for amorphous Si15Te85-xGex thin films. From these studies, it is also seen that multi state switching/multiple resistance levels of the material can be achieved by current controlled switching, the mechanisms of which have been further probed using XRD analysis and AFM studies. In addition, investigations have been carried out on the electrical switching behavior of amorphous Ge15Te85-xAgx thin film devices and optical band gap studies on amorphous Ge15Te85-xAgx thin films.
Chapter one of the thesis, gives a brief introduction to the limitations in existing memory technology and the alternative memory technologies that are being researched, based on which it can be inferred that PCM is a promising candidate for the next generation non volatile memory. This chapter also discusses the principle of using PCM to store data, realization of PCM using chalcogenides, the material properties to be considered in designing PCM, the trade offs in the process of design and the current trends in PCM technology.
Chapter two…
Advisors/Committee Members: Asokan, S.
Subjects/Keywords: Phase Change Memory (PCM); Amorphous Thin Films; Chalcogenide Glasses; Chalcogenide Glasses - Electrical Switching; Amorphous Thin Films - Optical Band Gap; Anorphous Thin Films - Electrical Switching; Amorphous Chalcogenide Thin Films; Silicon Telluride Germanium Amorphous Thin Films; Germanium Telluride Silver Amorphous Thin Films; Si–Te–Ge Thin Films; Si15Te75Ge10 Thin Films; Si15Te85-xGex Thin Films; Ge-Te-Ag Thin Films; Electronic Engineering
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Lakshmi, K. P. (2013). Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/2005/3359 ; http://etd.iisc.ernet.in/abstracts/4227/G25760-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Lakshmi, K P. “Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories.” 2013. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/2005/3359 ; http://etd.iisc.ernet.in/abstracts/4227/G25760-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Lakshmi, K P. “Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories.” 2013. Web. 19 Nov 2019.
Vancouver:
Lakshmi KP. Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories. [Internet] [Thesis]. Indian Institute of Science; 2013. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/2005/3359 ; http://etd.iisc.ernet.in/abstracts/4227/G25760-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Lakshmi KP. Studies on Si15Te85-xGex and Ge15Te85-xAgx Amorphous Thin Films for Possible Applications in Phase Change Memories. [Thesis]. Indian Institute of Science; 2013. Available from: http://etd.iisc.ernet.in/2005/3359 ; http://etd.iisc.ernet.in/abstracts/4227/G25760-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
16.
Das, Chandasree.
Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.
Degree: 2011, Indian Institute of Science
URL: http://hdl.handle.net/2005/2378
► Chalcogenide glass based Phase Change Memories (PCMs) are being considered recently as promising alternatives to conventional non-volatile Random Access Memories (NVRAMs). PCMs offer high performance…
(more)
▼ Chalcogenide glass based Phase Change Memories (PCMs) are being considered recently as promising alternatives to conventional non-volatile Random Access Memories (NVRAMs). PCMs offer high performance & low power consumption, in addition to other advantages, such as high scalability, high endurance and compatibility with complementary metal oxide semiconductors (CMOS) technologies. Basically PCM is a resistance variable non-volatile memory in which the memory bit state is defined by the resistance of the material. In this case, the initial ‘OFF’ state (logic zero) corresponds to the high resistance amorphous state and the logic 1 or ‘ON’ state corresponds to low resistance crystalline state.
The present thesis work deals with electrical, thermal, mechanical and optical characterization of certain tellurium based chalcogenide glasses in bulk and thin film form for phase change memory applications. A comparative study has been done on the electrical switching behavior of Ge-Te-Se & Ge-Te-Si amorphous thin film samples with their bulk counterparts. Further, electrical switching and thermal studies have been undertaken on bulk Ge-Te-Bi and Ge-Te-Sn series of samples. The composition dependence of switching voltages of bulk and thin film samples studied has been explained on the basis of different factors responsible for electrical switching. The thesis contains ten chapters:
Chapter 1 deals with a brief introduction on chalcogenides and their applicability in phase change memories. The glass transition phenomenon, synthesis of chalcogenide alloys, different structural models of amorphous semiconductors and electrical switching behavior are also discussed in detail in this chapter. Further, a brief description of optical and mechanical properties along with the principles of few characterization techniques used is discussed. Also, a brief overview on PCM application of chalcogenides is presented.
The second chapter provides the details of various experimental techniques used to measure electrical, thermal, optical and mechanical properties of few tellurium based chalcogenide glassy systems.
In the third chapter, the electrical switching behavior of amorphous Al23Te77 thin film devices, deposited in co-planar geometry, has been discussed. It is found that these samples exhibit memory type electrical switching. Scanning Electron Microscopic studies show the formation of a crystalline filament in the electrode region which is responsible for switching of the device from high resistance OFF state to low resistance ON state. The switching behavior of thin film Al-Te samples is found to be similar to that of bulk samples, with the threshold fields of bulk samples being higher. This has been understood on the basis of higher thermal conductance in bulk, which reduces the Joule heating and temperature rise in the electrode region.
Electrical switching and thermal behavior of bulk; melt quenched Ge18Te82-xBix glasses (1 ≤ x ≤ 4) are presented in chapter 4. Ge-Te-Bi glasses have been found to exhibit memory type electrical…
Advisors/Committee Members: Asokan, S, Rao, G Mohan.
Subjects/Keywords: Chalcogenide Glasses; Phase Change Memory (PCM); Thin Film Instruments; Chalcogenide Thin Films; Chalcogenide Glasses - Electrical Switching; Chalcogenide Glasses - Optical Properties; Tellurium Chalcogenide Glasses; Chalcogenide Glasses - Thermal Properties; Ge-Te-Bi Glasses; Materials Science
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Das, C. (2011). Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2378
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Das, Chandasree. “Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.” 2011. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/2378.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Das, Chandasree. “Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.” 2011. Web. 19 Nov 2019.
Vancouver:
Das C. Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. [Internet] [Thesis]. Indian Institute of Science; 2011. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/2378.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Das C. Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. [Thesis]. Indian Institute of Science; 2011. Available from: http://hdl.handle.net/2005/2378
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
17.
Das, Chandasree.
Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.
Degree: 2011, Indian Institute of Science
URL: http://etd.iisc.ernet.in/handle/2005/2378
;
http://etd.ncsi.iisc.ernet.in/abstracts/3061/G25140-Abs.pdf
► Chalcogenide glass based Phase Change Memories (PCMs) are being considered recently as promising alternatives to conventional non-volatile Random Access Memories (NVRAMs). PCMs offer high performance…
(more)
▼ Chalcogenide glass based Phase Change Memories (PCMs) are being considered recently as promising alternatives to conventional non-volatile Random Access Memories (NVRAMs). PCMs offer high performance & low power consumption, in addition to other advantages, such as high scalability, high endurance and compatibility with complementary metal oxide semiconductors (CMOS) technologies. Basically PCM is a resistance variable non-volatile memory in which the memory bit state is defined by the resistance of the material. In this case, the initial ‘OFF’ state (logic zero) corresponds to the high resistance amorphous state and the logic 1 or ‘ON’ state corresponds to low resistance crystalline state.
The present thesis work deals with electrical, thermal, mechanical and optical characterization of certain tellurium based chalcogenide glasses in bulk and thin film form for phase change memory applications. A comparative study has been done on the electrical switching behavior of Ge-Te-Se & Ge-Te-Si amorphous thin film samples with their bulk counterparts. Further, electrical switching and thermal studies have been undertaken on bulk Ge-Te-Bi and Ge-Te-Sn series of samples. The composition dependence of switching voltages of bulk and thin film samples studied has been explained on the basis of different factors responsible for electrical switching. The thesis contains ten chapters:
Chapter 1 deals with a brief introduction on chalcogenides and their applicability in phase change memories. The glass transition phenomenon, synthesis of chalcogenide alloys, different structural models of amorphous semiconductors and electrical switching behavior are also discussed in detail in this chapter. Further, a brief description of optical and mechanical properties along with the principles of few characterization techniques used is discussed. Also, a brief overview on PCM application of chalcogenides is presented.
The second chapter provides the details of various experimental techniques used to measure electrical, thermal, optical and mechanical properties of few tellurium based chalcogenide glassy systems.
In the third chapter, the electrical switching behavior of amorphous Al23Te77 thin film devices, deposited in co-planar geometry, has been discussed. It is found that these samples exhibit memory type electrical switching. Scanning Electron Microscopic studies show the formation of a crystalline filament in the electrode region which is responsible for switching of the device from high resistance OFF state to low resistance ON state. The switching behavior of thin film Al-Te samples is found to be similar to that of bulk samples, with the threshold fields of bulk samples being higher. This has been understood on the basis of higher thermal conductance in bulk, which reduces the Joule heating and temperature rise in the electrode region.
Electrical switching and thermal behavior of bulk; melt quenched Ge18Te82-xBix glasses (1 ≤ x ≤ 4) are presented in chapter 4. Ge-Te-Bi glasses have been found to exhibit memory type electrical…
Advisors/Committee Members: Asokan, S, Rao, G Mohan.
Subjects/Keywords: Chalcogenide Glasses; Phase Change Memory (PCM); Thin Film Instruments; Chalcogenide Thin Films; Chalcogenide Glasses - Electrical Switching; Chalcogenide Glasses - Optical Properties; Tellurium Chalcogenide Glasses; Chalcogenide Glasses - Thermal Properties; Ge-Te-Bi Glasses; Materials Science
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Das, C. (2011). Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/2378 ; http://etd.ncsi.iisc.ernet.in/abstracts/3061/G25140-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Das, Chandasree. “Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.” 2011. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/handle/2005/2378 ; http://etd.ncsi.iisc.ernet.in/abstracts/3061/G25140-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Das, Chandasree. “Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications.” 2011. Web. 19 Nov 2019.
Vancouver:
Das C. Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. [Internet] [Thesis]. Indian Institute of Science; 2011. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/handle/2005/2378 ; http://etd.ncsi.iisc.ernet.in/abstracts/3061/G25140-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Das C. Investigations On Certain Tellurium Based Bulk Chalcogenide Glasses And Amorphous Chalcogenide Films Having Phase Change Memory (PCM) Applications. [Thesis]. Indian Institute of Science; 2011. Available from: http://etd.iisc.ernet.in/handle/2005/2378 ; http://etd.ncsi.iisc.ernet.in/abstracts/3061/G25140-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
18.
Shivananju, B N.
Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques.
Degree: 2013, Indian Institute of Science
URL: http://hdl.handle.net/2005/2611
► In this thesis work, a systematic quantitative study has been undertaken, on the performance of etched fiber Bragg Grating (FBG) sensors in the investigation of…
(more)
▼ In this thesis work, a systematic quantitative study has been undertaken, on the performance of etched fiber Bragg Grating (FBG) sensors in the investigation of surface molecular adsorption in real-time; it is shown that the limit of detection (LOD) of FBGs etched below 2 microns diameter, is better compared to prominent optical label-free molecular sensing techniques such as Surface Plasmon Resonance (SPR).
Novel fiber optic sensors based on FBG and etched FBG with various nano materials (polyelectrolytes, carbon nanotubes, hydrogel, metals and chalcogenides) coated on the surface of the core or cladding, have been proposed for sensing multi parameters such as pH, protein, humidity, gas, strain, temperature, and light etc. Besides being reproducible and repeatable, the proposed methods are fast, compact, and highly sensitive.
A novel optical instrument has also been developed to measure angular deviation, binocular deviation and refractive index of glass slabs, and liquids, based on a shadow casting technique. This method uses the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by a distorted light beam from the transparent test specimen relative to a reference pattern.
Advisors/Committee Members: Asokan, S, Varma, Manoj M.
Subjects/Keywords: Optical Shadow Casting; Fiber Bragg Grating; Fiber Bragg Grating Sensors; Etched Fiber Bragg Grating; Metal Coated Fiber Bragg Grating; Hydrogel Coated Fiber Bragg Grating; Chalcogenide Coated Fiber Bragg Grating; Surface Molecular Adsorption; Fiber Optic Sensors; Fiber Bragg Gratings - Photonics; Carbon Nanotube Coated Fiber Bragg Grating; Instrumentation
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APA ·
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MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Shivananju, B. N. (2013). Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2611
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Shivananju, B N. “Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques.” 2013. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/2611.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Shivananju, B N. “Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques.” 2013. Web. 19 Nov 2019.
Vancouver:
Shivananju BN. Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques. [Internet] [Thesis]. Indian Institute of Science; 2013. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/2611.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Shivananju BN. Advanced Multifunctional Bulk Optical & Fiber Bragg Grating Sensing Techniques. [Thesis]. Indian Institute of Science; 2013. Available from: http://hdl.handle.net/2005/2611
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
19.
Prakash, S.
Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.
Degree: 1996, Indian Institute of Science
URL: http://hdl.handle.net/2005/1704
Subjects/Keywords: Amorphous Semiconductors Switching; Melt Quenching; Electric Switches; Semiconductors; Chalcogenides Semiconductors; Ge-As-Te Glasses; Applied Physics
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APA (6th Edition):
Prakash, S. (1996). Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/1704
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Prakash, S. “Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.” 1996. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://hdl.handle.net/2005/1704.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Prakash, S. “Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.” 1996. Web. 19 Nov 2019.
Vancouver:
Prakash S. Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. [Internet] [Thesis]. Indian Institute of Science; 1996. [cited 2019 Nov 19].
Available from: http://hdl.handle.net/2005/1704.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Prakash S. Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. [Thesis]. Indian Institute of Science; 1996. Available from: http://hdl.handle.net/2005/1704
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
20.
Prakash, S.
Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.
Degree: 1996, Indian Institute of Science
URL: http://etd.iisc.ernet.in/handle/2005/1704
;
http://etd.ncsi.iisc.ernet.in/abstracts/2197/G14777-Abs.pdf
Subjects/Keywords: Amorphous Semiconductors Switching; Melt Quenching; Electric Switches; Semiconductors; Chalcogenides Semiconductors; Ge-As-Te Glasses; Applied Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Prakash, S. (1996). Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/1704 ; http://etd.ncsi.iisc.ernet.in/abstracts/2197/G14777-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Prakash, S. “Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.” 1996. Thesis, Indian Institute of Science. Accessed November 19, 2019.
http://etd.iisc.ernet.in/handle/2005/1704 ; http://etd.ncsi.iisc.ernet.in/abstracts/2197/G14777-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Prakash, S. “Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications.” 1996. Web. 19 Nov 2019.
Vancouver:
Prakash S. Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. [Internet] [Thesis]. Indian Institute of Science; 1996. [cited 2019 Nov 19].
Available from: http://etd.iisc.ernet.in/handle/2005/1704 ; http://etd.ncsi.iisc.ernet.in/abstracts/2197/G14777-Abs.pdf.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Prakash S. Electrical Switching Investigations To Design Amorphous Semiconductors For Device Applications. [Thesis]. Indian Institute of Science; 1996. Available from: http://etd.iisc.ernet.in/handle/2005/1704 ; http://etd.ncsi.iisc.ernet.in/abstracts/2197/G14777-Abs.pdf
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
. 
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