EXCITON LOCALIZATION IN SUBMONOLAYER INAS/GAAS MULTIPLE QUANTUM-WELLS

We study the optical transitions and their relation to the crystal potential in ultrathin InAs/GaAs multiple quantum wells. Photoluminescence, photoluminescence excitation, and photoreflectance measurements evidence strong localization of the heavy- and light-hole excitons in submonolayer wide InAs quantum wells. A tight-binding model in the linear-chain approximation explains these results in terms of particle localization at the two-dimensional potential discontinuity produced by the insertion of the InAs plane in the host GaAs matrix. © 1990 The American Physical Society.