Negative charged excitons in double barrier diodes

Abstract

We have studied the effects of excitonic complexes formation, such as excitons and trions, on the optical and on transport properties of GaAs–GaAlAs n–i–n double barrier diodes, by measuring the current–voltage characteristics and the photoluminescence emission, as function of bias. The observation of a pre-resonance shoulder in the I(V) curves, under high laser intensities, and a negative charged excitons in the photoluminescence spectra, under the same bias conditions, were associated to the dissociation of these complexes either by thermal excitation or by scattering with ‘free’ carriers in the quantum well layer. A simple rate equation model allows us to explain the kinetics of the excitonic complexes in double barrier devices.