Hot-phonon generation in GaAs/Al[sub [ital x]]Ga[sub 1[minus][ital x]]As superlattices: Observations and implications on the coherence length of LO phonons
- Department of Physics and Center for Laser Research, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
- Department of Electrical Engineering, University of California at San Diego, La Jolla, California 92093 (United States)
- Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)
Using picosecond Raman scattering, hot-phonon occupation numbers ([ital N]) of GaAs and GaAs-like LO phonons have been studied over a wide range of structural parameters in more than 30 GaAs/Al[sub [ital x]]Ga[sub 1[minus][ital x]]As superlattices. In addition, simultaneous measurements of these LO phonon modes in bulk GaAs and Al[sub [ital x]]Ga[sub 1[minus][ital x]]As alloys are made for comparison. [ital N] values of both GaAs and GaAs-like modes of the superlattices are comparable to or larger than those of bulk GaAs or Al[sub [ital x]]Ga[sub 1[minus][ital x]]As alloys for [ital x][lt]0.2. On the other hand, [ital N] values of GaAs or GaAs-like LO phonons are much smaller for [ital x][gt]0.35, unless the barrier widths are very thin ([lt]15 A). The implications of our results on spatial properties of LO phonons are discussed and compared with relevant theoretical and experimental studies.
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 6869898
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:8; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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