Confined-to-propagating transition of LO phonons in GaAs/Al sub x Ga sub 1 minus x As superlattices observed by picosecond Raman scattering

Journal Article · Sun Feb 16 23:00:00 EST 1992 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.68.1002· OSTI ID:7272202

Kim, D; Bouchalkha, A; Jacob, J M; Zhou, J F; Song, J J ^[1]; Klem, J F ^[2]

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1. Center for Laser Research and Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)
2. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

We report the first observation of a confined-to-propagating transition of LO phonons in GaAs/Al{sub {ital x}}Ga{sub 1{minus}{ital x}}As superlattices (SL's). Picosecond Raman scattering was used to investigate the generation rate of nonequilibrium GaAs LO phonons in two series of GaAs/Al{sub {ital x}}Ga{sub 1{minus}{ital x}}As SL's with constant GaAs layer widths ({ital L}{sub {ital z}}) and {ital x}, while the Al{sub {ital x}}Ga{sub 1{minus}{ital x}}As layer widths ({ital L}{sub {ital b}}'s) varied. In both series we have observed a sudden increase in the generation rate of the Raman-active hot phonons as {ital L}{sub {ital b}} decreased over a narrow range. We demonstrate that this abrupt increase is due to the sharp transition from the so-called confined to propagating LO phonons. From our results we have determined the GaAs/LO phonon penetration depth into the Al{sub {ital x}}Ga{sub 1{minus}{ital x}}As layers.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7272202
• Journal Information: Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 68:7; ISSN PRLTA; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CONFINEMENT
DIMENSIONS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
IRRADIATION
LASER SPECTROSCOPY
PHONONS
PNICTIDES
PULSED IRRADIATION
QUASI PARTICLES
RAMAN SPECTROSCOPY
SPECTROSCOPY
SUPERLATTICES
THICKNESS
WAVE PROPAGATION