Evaluation of carrier density distribution and population inversion caused by Γ-X scattering in GaAs/AlAs multi-quantum wells

摘要

We investigated the electric field dependence of photoluminescence (PL) spectra in four kinds of GaAs/AlAs multi-quantum well (MQW) structures. Only one of them exhibited various PL spectra in spite of having a similar sample structure in the MQW. The PL spectra reveal several signals in the shorter wavelength region due to the combination effect of interface roughness and Γ-X scattering. We also estimated the carrier densities of excited states by observed PL intensities and calculation of overlap integrals of wavefunctions between electron and heavy hole states. The observation of PL signals from excited states in the MQW provides fruitful information on carrier densities and structural imperfection of MQWs.