Raman analysis of Si/GaAs multiple quantum wells
Abstract
Raman scattering experiments on Si/GaAs multiple quantum wells are reported. Samples were grown by MBE in the temperature range (500--540)^circ C, with Si-layers thickness in the (1--4)MLs range; XRD and TEM analysis showed very high Si-layer homogeneity. The 2D character of plasmonic excitations was unambiguously deduced by the position of the ω- signal appearing between TO and LO GaAs modes. Furthermore, intersubband separation was inferred from the analysis of ω+ and ω- energy positions. The large values found ( ~100 meV) are not compatible with Coulomb potential confinement alone and point at the existence of a type I heterojunction. Comparison of experimental data with the outcome of an empirical tight-binding calculation yielded an estimate of Si/GaAs valence band offset ( ~0.22±0.04) eV and prove that Si layers act as potential well for electrons.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.E2708C