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)

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Metallurgical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Shah, Syed Ismat Ullah

• Engineering, Materials Science

Identifier

(UMI)AAI8623406

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71834