Photoluminescence properties of a GaN0.015As0.985/GaAs single quantum wellunder short pulse excitation

Under short pulse laser excitation, we have observed an extra high-energy p hotoluminescence (PL) emission from GaNAs/GaAs single quantum wells (QWs). It dominates the PL spectra under high excitation and/or at high temperatur e. By measuring the PL dependence on both temperature and excitation power and by analyzing the time-resolved PL results, we have attributed the PL pe ak to the recombination of delocalized excitons in QWs. Furthermore, a comp etition process between localized and delocalized excitons is observed in t he temperature-dependent PL spectra under the short pulse excitation. This competition is believed to be responsible for the temperature-induced S-sha ped PL shift often observed in the disordered alloy semiconductor system un der continuous-wave excitation. (C) 2001 American Institute of Physics.