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You searched for +publisher:"University of North Texas" +contributor:("Reidy, Rick"). Showing records 1 – 2 of 2 total matches.

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University of North Texas

1. Cai, Bimin. The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films.

Degree: 2019, University of North Texas

Recent progress in layered transition metal dichalcogenides (TMDs) has led to various promising electronic and optoelectronic applications. However, the structure of materials plays a critical role in electronic and optoelectronic devices, and determines performance. Electronic and optoelectronic devices typically consist of multiple layers that form electrical homojunctions or heterojunctions. Therefore, in a device it can be expected that a WS2 layer may serve as the substrate for a subsequent layer in a multilayer device stack and determine how the layer grows. In transistor structures, roughness at the channel/gate dielectric interface introduces field variations and charge scattering. Therefore, understanding the relations between processing, surface morphology and properties is important. In this project, the effects of pulsed laser deposition (PLD) processing conditions on the surface morphology of few layered WS2 films were studied. WS2 films were synthesized under processing conditions that represent the extremes of surface supersaturation and kinetic energy transfer from the flux to the growing films, and evolution of the surface morphology was studied. The specific conditions were 1Hz/50mJ, 10Hz/50mJ, 1Hz/300mJ, and 10Hz/300mJ respectively. Combining AFM, XRD and Raman analyses, it was determined that deposition at 10Hz/300mJ, provided the best structural properties and surface morphology. Growth appeared to be 3D-cluster, and was governed by supersaturation rather than by surface diffusion processes. No clear correlation between mobility and surface roughness was found. Hall measurements and XPS data show the highest mobility was obtained with the highest S/W ratio, indicating that point defect scattering rather than scattering from surface roughness was dominant. Advisors/Committee Members: Shepherd, Nigel, Reidy, Rick F., Bouanani, Mohamed El.

Subjects/Keywords: PLD; Processing Conditions; Surface Morphology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Cai, B. (2019). The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films. (Thesis). University of North Texas. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc1505277/

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):

Cai, Bimin. “The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films.” 2019. Thesis, University of North Texas. Accessed November 27, 2020. https://digital.library.unt.edu/ark:/67531/metadc1505277/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Cai, Bimin. “The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films.” 2019. Web. 27 Nov 2020.

Vancouver:

Cai B. The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films. [Internet] [Thesis]. University of North Texas; 2019. [cited 2020 Nov 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc1505277/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Cai B. The Effect of Process Conditions on the Surface Morphology of Few-Layered WS2 Thin Films. [Thesis]. University of North Texas; 2019. Available from: https://digital.library.unt.edu/ark:/67531/metadc1505277/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of North Texas

2. Rose, Kyle. Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate.

Degree: 2020, University of North Texas

An in-depth study of Al2W3O12 negative thermal expansion (NTE) ceramic was performed, focused on synthesis, phase mappings, and the underlying mechanisms shown to be responsible for NTE. Review of the literature has shown inconsistencies in reported values of the dilatometry measured coefficients of thermal expansion, and the temperature for the known monoclinic to orthorhombic phase transition. Two synthesis techniques are introduced: an ionic-liquid non-hydrolytic sol-gel synthesis route; and a low temperature solid state reaction synthesis for Al2W3O12. X-ray diffraction, Raman spectroscopy, and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) were used to verify the techniques. Two differential scanning calorimetry (DSC) experiments (high and low temperature) were performed on the material showing the transition between -5 and -20 °C and no other phase changes until a reported degradation above 1100 °C. Extensive dilatometry on the material led to the discovery of elastic transitions occurring in the polycrystalline sample capable of explaining the inconsistencies in reported dilatometry results. This is further developed into a proposed model defining the regions between these transitions. Each region has a different thermal expansion as well as a direct effect on the reaction of the material upon cooling. This proposed model may allow more consistent reporting of dilatometry results for NTE materials. Raman spectroscopy was performed from 25-725 °C on the material showing both a joining in the tungsten-oxygen bending modes as well as a broadening in the tungsten-oxygen stretching modes. This is consistent with Al-O-W angle changes along the same temperature range reported in literature as well as the transverse vibrational modes responsible for NTE. Advisors/Committee Members: Reidy, Rick, Scharf, Thomas, Du, Jincheng.

Subjects/Keywords: Negative Thermal Expansion; Synthesis; Dilatometry; High Temperature Raman; Al2W3O12; A2M3O12; Vibration mechanisms

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Rose, K. (2020). Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate. (Thesis). University of North Texas. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc1703275/

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):

Rose, Kyle. “Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate.” 2020. Thesis, University of North Texas. Accessed November 27, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703275/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Rose, Kyle. “Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate.” 2020. Web. 27 Nov 2020.

Vancouver:

Rose K. Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate. [Internet] [Thesis]. University of North Texas; 2020. [cited 2020 Nov 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc1703275/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rose K. Synthesis, Phase Development, and the Mechanism for Negative Thermal Expansion in Aluminum Tungstate. [Thesis]. University of North Texas; 2020. Available from: https://digital.library.unt.edu/ark:/67531/metadc1703275/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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