Direct optical observation of compositional fluctuation in GaAs1-xNx by near-field photoluminescence spectroscopy and microscopy with high spatial resolution

摘要

We describe imaging spectroscopy of GaAs1-xNx/GaAs single quantum wells using low-temperature near-field scanning optical microscope with a high spatial resolution of 35 nm. In near-field photoluminescence spectra of a GaAs1-xNx/GaAs(x=0.7%) quantum well, the narrow spectral peaks with a point emission spatial profile (localized exciton emission) come from local N-rich regions (spontaneous N clusters), and the broad peaks with spatial extension (delocalized exciton emission) are random alloy regions. Localized exciton emissions due to spontaneous N clusters are also observed in GaAs1-xNx with a higher N concentration (x=1.2%). (C) 2004 American Institute of Physics.