Engineering Commons^™

Virtual Substrate Synthesis For Low-Cost High Efficiency Iii-V, Sean J. Babcock

Electrical & Computer Engineering Theses & Dissertations

The use of the low-cost thin-film vapor-liquid-solid (TF-VLS) method in the manufacturing of III-V solar cell substrates has the potential to provide a lightweight, flexible, and cheaper alternative to traditional III-V substrates typical of state-of-the- art power generation technology. The TF-VLS process has been shown to produce high optoelectronic quality polycrystalline InP on lightweight flexible metal foils. In this work, this novel method is applied to the growth of binary and ternary III-V materials which include: InP, InAs, and InGaP on Mo foils and/or sputtered Mo on Si wafers.

As a result of InP trials, powder XRD measurements have identified …

Reflection High-Energy Electron Diffraction Studies Of Indium Phosphide (100) And Growth On Indium And Indium Nitride On Silicon (100), Mohamed Abd-Elsattar Hafez

Electrical & Computer Engineering Theses & Dissertations

Study of the effects of atomic hydrogen exposure on structure and morphology of semiconductor surfaces is important for fundamental properties and applications. In this dissertation, the electron yield of a hydrogen-cleaned indium phosphide (InP) surface was measured and correlated to the development of the surface morphology, which was monitored by in situ reflection high-energy electron diffraction (RHEED). Atomic hydrogen treatment produced a clean, well-ordered, and (2x4)-reconstructed InP(100) surface. The quantum efficiency, after activation to negative electron affinity, and the secondary electron emission were shown to increase with hydrogen cleaning time. RHEED patterns of low-index InP(100) surface were modified by the …

Melting And Solidification Study Of Indium And Bismuth Nanocrystals Using Reflection High-Energy Electron Diffraction, Mohamed K. Zayed

Electrical & Computer Engineering Theses & Dissertations

As technology begins to utilize nanocrystals for many chemical, biological, medical, electrical, and optoelectrical applications, there is a growing need for an understanding of their fundamental properties. The study of melting and solidification of nanocrystals is of interest to fundamental understanding of the effect of reduced size and crystal shape on the solid-liquid phase transition. Melting and solidification of as-deposited and recrystallized indium and bismuth nanocrystals were studied using reflection high-energy electron diffraction (RHEED). The nanocrystals were thermally deposited on highly oriented 002-graphite substrate at different deposition temperatures. The growth dynamics of the nanocrystals was studied using in situ RHEED …