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Title:Crystal Growth, Atomic Ordering, Phase Transitions in Pseudobinary Constituents of the Metastable Quaternary (gallium-Antimony)(1-X)(germanium(2)(1-Y)tin(2y))(x) (Semiconductor, Sputtering, Ion Bombardment, X-Ray Diffraction, Electron Microscopy)
Author(s):Shah, Syed Ismat Ullah
Department / Program:Metallurgy and Mining Engineering
Discipline:Metallurgical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Engineering, Materials Science
Abstract:Thin film single crystal growth of metastable semiconducting (GaSb)(,1-x)(Ge(,2))(,x), Ge(,1-x)Sn(,x), and (GaSb)(,(1-x))(Ge(,2(1-y))Sn(,2y))(,x) alloys is studied as a function of growth parameters. The effects of low-energy ion bombardment of growing films during vapor phase epitaxy are considered in some detail. Ion bombardment plays an important and sometimes dominant role in controlling the growth kinetics and physical properties of films deposited by glow discharge sputter deposition. A combination of x-ray diffraction, Raman spectroscopy and extended x-ray-absorption fine-structure analyses are used to show that an order-disorder structural transition from zincblende to diamond occurs in metastable (GaSb)(,1-x)(Ge(,2))(,x) and (GaSb)(,(1-x))(Ge(,2(1-y))Sn(,2y))(,x) alloys at a critical composition x(,c) even though the short-range order remains perfect throughout, i.e., there is no evidence of Ga-Ga or Sb-Sb bonds in either the zincblende or the diamond structure. X-ray diffraction and hot stage transmission analyses are done to study metastable growth phase diagrams and phase transformation reaction paths for these metastable alloys. The transformation from single-phase metastable state to phase-separated equilibrium state involves many intermediate steps which consist either metastable phases, equilibrium phases, or a combination of both.
Issue Date:1986
Type:Text
Description:108 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
URI:http://hdl.handle.net/2142/71834
Other Identifier(s):(UMI)AAI8623406
Date Available in IDEALS:2014-12-16
Date Deposited:1986


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