Near-field magneto-photoluminescence of quantum-dot-like composition fluctuations in GaAsN and InGaAsN alloys

摘要

Near-field magneto-photoluminescence scanning microscopy has been used to investigate the structural and optical properties of quantum-dot (QD)-like compositional fluctuations in GaAsN and InGaAsN alloys. Sharp spectral lines (halfwidth 0.5-2 meV) from these QDs are observed at T < 70 K, and their Zeeman splitting and diamagnetic shifts are used to determine the size (r similar to 6-18 mn), density (similar to 100 mum(-3)), and nitrogen composition. Near-field scanning images reveal phase separation effects in the distribution of nitrogen, but little effect appears from the presence or absence of indium. Indium does have a strong effect on the exciton g-factor for observations in a magnetic field. (C) 2003 Elsevier B.V. All rights reserved.