Micro-Raman scattering study of InGaAs/(AlAs)/AlAsSb quantum wells grown by molecular beam epitaxy

Raman spectra of In 0.80Ga 0.20As/(AlAs)/AlAs 056Sb 0.44 quantum wells (QWs) grown on (0 0 1)-InP substrates by molecular beam epitaxy were measured in backscattering along Z | | [ 0 0 1 ] and x | | [ 1 1 0 ] directions, i.e. from (0 0 1) grown and (1 1 0) cleaved surfaces, with microprobes. Confine...

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Bibliographic Details
Published in:Journal of crystal growth 2005-05, Vol.278 (1), p.178-182
Main Authors: Mozume, T., Kasai, J.
Format: Article
Language:English
Subjects:
A1. Plasmon-LO-phonon coupling
A1. Raman scattering
A3. Molecular beam epitaxy
A3. Quantum wells
B1. InGaAs/AlAsSb
B2. Semiconducting III–V materials
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Materials science
Methods of deposition of films and coatings
film growth and epitaxy
Molecular, atomic, ion, and chemical beam epitaxy
Nanoscale materials and structures: fabrication and characterization
Physics
Quantum wells
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Summary:Raman spectra of In 0.80Ga 0.20As/(AlAs)/AlAs 056Sb 0.44 quantum wells (QWs) grown on (0 0 1)-InP substrates by molecular beam epitaxy were measured in backscattering along Z | | [ 0 0 1 ] and x | | [ 1 1 0 ] directions, i.e. from (0 0 1) grown and (1 1 0) cleaved surfaces, with microprobes. Confined longitudinal-optic (LO) and transverse-optic (TO) phonons with wave vector q either parallel or normal to the Z axis were studied in all the independent scattering geometries. The Raman scattering spectra from (0 0 1) surfaces show two-mode behavior in the InGaAs band, while single mode behavior is confirmed in the AlAsSb band, consistent with the previous results. The GaAs-like LO- phonon peak splits into two peaks that can be attributed to the confined GaAs-like LO-phonon mode and the intermediate frequency plasmon-LO-phonon coupled mode. A drastic change in the Raman spectra is observed when the transferred momentum is changed from the Z-axis to x-axis. The Raman spectra in the x ( Zy ) x ¯ geometry are dominated by TO-confined phonons, whereas LO-confined phonons are dominated in the x ( ZZ ) x ¯ geometry, consistent with the selection rules, although in other configurations no signals are observed inconsistent with the selection rules.
ISSN:0022-0248
1873-5002
DOI:10.1016/j.jcrysgro.2004.12.072