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Title: Raman scattering studies of strain effects in (100) and (311)B GaAs{sub 1−x}Bi{sub x} epitaxial layers

We report room-temperature Raman studies of strained (100) and (311)B GaAs{sub 1−x}Bi{sub x} epitaxial layers for x ≤ 0.039. The Raman spectra exhibit a two-mode behavior, as well as disorder-activated GaAs-like phonons. The experimental results show that the GaAs-like LO(Γ) mode experiences a strong composition-dependent redshift as a result of alloying. The peak frequency decreases linearly from the value for pure GaAs (∼293 cm{sup −1}) with the alloyed Bi fraction x and the introduced in-plane lattice strain ε{sub ∥}, by Δω{sub LO}=Δω{sub alloy}−Δω{sub strain}. X-ray diffraction measurements are used to determine x and ε{sub ∥} allowing Δω{sub alloy} to be decoupled and is estimated to be −12(±4) cm{sup −1}/x for (100) GaAs{sub 1−x}Bi{sub x}. Δω{sub LO} is measured to be roughly double for samples grown on (311)B-oriented substrates to that of (100) GaAs. This large difference in redshift is accounted for by examining the Bi induced strain, effects from alloying, and defects formed during high-index (311)B crystal growth.
Authors:
;  [1] ;  [2] ; ;  [3]
  1. Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)
  2. School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center, University of Nottingham, Nottingham NG7 2RD (United Kingdom)
  3. Department of Physics, College of Sciences, Al Imam Muhammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623 (Saudi Arabia)
Publication Date:
OSTI Identifier:
22258743
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALLOYS; EPITAXY; GALLIUM ARSENIDES; LAYERS; PHONONS; RAMAN EFFECT; RAMAN SPECTRA; RED SHIFT; STRAINS; X-RAY DIFFRACTION