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You searched for +publisher:"University of North Carolina" +contributor:("Pinion, Christopher"). One record found.

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University of North Carolina

1. Pinion, Christopher. Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology.

Degree: Chemistry, 2017, University of North Carolina

Precise patterning of semiconductor materials utilizing top-down lithographic techniques is integral to the advanced electronics we use on a daily basis. However, continuing development of these lithographic technologies often results in the trade-off of either high cost or low throughput, and three-dimensional (3D) patterning can be difficult to achieve. Bottom-up, chemical methods to control the 3D nanoscale morphology of semiconductor nanostructures have received significant attention as a complementary technique. Semiconductor nanowires, nanoscale filaments of semiconductor material ~10-500 nm in diameter and ~1-50 microns in length, are an especially promising platform because the wire composition can be modulated during growth and the high aspect ratio, one-dimensional structure enables integration in a range of devices. In this thesis, we first report a bottom-up method to break the conventional “wire” symmetry and synthetically encode a high-resolution array of arbitrary shapes along the nanowire growth axis. Rapid modulation of phosphorus doping combined with selective wet-chemical etching enables morphological features as small as 10 nm to be patterned over wires more than 50 μm in length. Next, our focus shifts to more fundamental studies of the nanowire synthetic mechanisms. We presented comprehensive experimental measurements on the growth rate of Au catalyzed Si nanowires and developed a kinetic model of vapor-liquid-solid growth. Our analysis revealed an abrupt transition from a diameter-independent growth rate that is limited by incorporation to a diameter-dependent growth rate that is limited by crystallization. While investigating the vapor-liquid-solid mechanism, we noticed instances of unique catalyst behavior. Upon further study, we showed that it is possible to instantaneously and reversibly switch the phase of the catalyst between a liquid and superheated solid state under isothermal conditions above the eutectic temperature. The solid catalyst induces a vapor-solid-solid growth mechanism, which provides atomic-level control of dopant atoms in the nanowire. Finally, we explored a promising application of nanowires by investigating the potential for complex silicon nanowires to serve as a platform for next-generation photovoltaic devices. We reviewed the synthesis, electrical, and optical characteristics of core/shell Si nanowires that are sub-wavelength in diameter and contain radial p-n junctions. We highlighted the unique features of these nanowires, such as optical antenna effects that concentrate light and intense built-in electric fields that enable ultrafast charge-carrier separation. Based on these observations we advocate for a paradigm in which nanowires are arranged in periodic horizontal arrays to form ultrathin devices. Advisors/Committee Members: Pinion, Christopher, Cahoon, James, Kanai, Yosuke, Warren, Scott, Atkin, Joanna, Leibfarth, Frank.

Subjects/Keywords: College of Arts and Sciences; Department of Chemistry

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

APA (6th Edition):

Pinion, C. (2017). Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology. (Thesis). University of North Carolina. Retrieved from https://cdr.lib.unc.edu/record/uuid:a884a90e-61f0-431c-ae01-6ada1d0430e3

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):

Pinion, Christopher. “Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology.” 2017. Thesis, University of North Carolina. Accessed December 01, 2020. https://cdr.lib.unc.edu/record/uuid:a884a90e-61f0-431c-ae01-6ada1d0430e3.

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

MLA Handbook (7th Edition):

Pinion, Christopher. “Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology.” 2017. Web. 01 Dec 2020.

Vancouver:

Pinion C. Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology. [Internet] [Thesis]. University of North Carolina; 2017. [cited 2020 Dec 01]. Available from: https://cdr.lib.unc.edu/record/uuid:a884a90e-61f0-431c-ae01-6ada1d0430e3.

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

Council of Science Editors:

Pinion C. Understanding the Vapor-Liquid-Solid and Vapor-Solid-Solid Mechanisms of Si Nanowire Growth to Synthetically Encode Precise Nanoscale Morphology. [Thesis]. University of North Carolina; 2017. Available from: https://cdr.lib.unc.edu/record/uuid:a884a90e-61f0-431c-ae01-6ada1d0430e3

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

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