Spectroscopic investigations of photoinduced changes of the spatial distribution of charge carriers in modulation-doped quantum-well structures.

Abstract

We investigated the photoinduced changes of the spatial distribution of the free holes in p-type modulation-doped GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As heterostructures by measuring the energy of the quantum-well luminescence, which is conditioned by the many-particle effect of band-gap renormalization and the excitonic interactions between the electrons and holes. A conventional chopper technique with millisecond time resolution permitted us to study the dynamics of the hole density variations in the quantum wells. The strength of excitonic effects on the luminescence signals could be estimated by application of a magnetic field oriented parallel to the growth direction of the samples. \textcopyright{} 1996 The American Physical Society.