Raman scattering studies of strain effects in (100) and (311)B GaAs{sub 1−x}Bi{sub x} epitaxial layers
- Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)
- School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center, University of Nottingham, Nottingham NG7 2RD (United Kingdom)
- Department of Physics, College of Sciences, Al Imam Muhammad Ibn Saud Islamic University (IMSIU), Riyadh, 11623 (Saudi Arabia)
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.
- OSTI ID:
- 22258743
- Journal Information:
- Journal of Applied Physics, Vol. 114, Issue 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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