21 October 1992 Hot-phonon generation by split-off hole band electrons in AlxGa1-xAs alloys investigated by picosecond Raman scattering
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Abstract
The initial generation of hot LO phonons by the relaxation of hot carriers in GaAs and AlxGa1-xAs alloy semiconductors is studied. Within the initial 2 ps of photoexcitation, only those electrons originating from the split-off hole bands are found to generate a significant number of (Gamma) -valley hot phonons when photon energies of 2.33 eV are used. A picosecond Raman scattering technique is used to determine the hot phonon occupation number in a series of MBE grown AlxGa1-xAs samples with 0 17 cm-3. A model based upon the instantaneous thermalization of hot electrons photoexcited from the split-off hole bands is used to fit our data. We have obtained very good agreement between experiment and theory. This work provides a clear understanding to the relaxation of (Gamma) valley hot electrons by the generation of hot phonons on subpicosecond and picosecond time scales, which has long standing implications to previous time resolved Raman experiments.
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John M. Jacob, D. S. Kim, Jin Fu Zhou, Jin-Joo Song, "Hot-phonon generation by split-off hole band electrons in AlxGa1-xAs alloys investigated by picosecond Raman scattering", Proc. SPIE 1677, Ultrafast Lasers Probe Phenomena in Semiconductors and Superconductors, (21 October 1992); doi: 10.1117/12.137696; https://doi.org/10.1117/12.137696
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