Energy loss rate of excitons in GaN

The cooling of a hot photoexcited exciton distribution in wurtzite GaN is s tudied by time-resolved photoluminescence measurements on the longitudinal optical phonon replicas of the free exciton. The temperature of the exciton s decreases for sample temperatures below 60 K within 150 ps down to the la ttice temperature. The transient temperature is theoretically described in terms of exciton-phonon scattering via an acoustic deformation potential of 13 eV. (C) 1999 Elsevier Science B.V. All rights reserved.