Observation of wire width fluctuations in the optical spectra of GaAs–AlGaAs V-groove quantum wires

Abstract

Optical spectroscopy of a single GaAs–AlGaAs V-groove quantum wire is reported. Photoluminescence spectra are recorded over a five order-of-magnitude variation of incident laser power. With decreasing laser power, a continuous transition is observed from multiple wire subband occupancy to single subband occupancy through to the observation of the recombination of excitons localized by discrete potential fluctuations. The effect of single monolayer wire thickness fluctuations on the subband transitions is calculated using a finite difference technique which includes the Luttinger Hamiltonian description of the valence band states. These calculations indicate that the main contribution to the exciton localization potential is probably monolayer fluctuations of the wire thickness.