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

Optical spectroscopy of a single GaAs-AlGaAs V-groove quantum wire is repor ted. Photoluminescence spectra are recorded over a five order-of-magnitude variation of incident laser power. With decreasing laser power, a continuou s transition is observed from multiple wire subband occupancy to single sub band occupancy through to the observation of the recombination of excitons localized by discrete potential fluctuations. The effect of single monolaye r wire thickness fluctuations on the subband transitions is calculated usin g a finite difference technique which includes the Luttinger Hamiltonian de scription of the valence band states. These calculations indicate that the main contribution to the exciton localization potential is probably monolay er fluctuations of the wire thickness. (C) 1998 American Institute of Physi cs. [S00036-951(98)04449-0].