Acceptor-induced resonance Raman scattering below the E_0 gap in GaAs at low temperature

摘要

Impurity-related interband optical transitions has importance at low temperature, and they may contribute significantly to the Raman polarizability. It has been found that the impurity luminescence hampers the study of intrinsic Raman scattering below E_0 gap in GaAs [1]. Here we focus on the resonance Raman scattering (RRS) at shallow acceptor level in GaAs. We find that the resonance occurs at the (e,A~0) threshold and the Raman scattering selection rules are broken. We also find that the multi-phonon scattering by acoustic phonons happens when the excitation energy is above the (e, A~0) threshold. The interpretations of these phenomena are presented.