Time-resolved photoluminescence spectra ofGaxIn1−xP under picosecond-laser-pulse excitation measured by a streak camera

We have measured the time-resolved photoluminescence spectra of ${\mathrm{Ga}}_{\mathrm{x}}$ ${\mathrm{In}}_{1\mathrm{-}\mathrm{x}}$P (x=0.56) with 10-ps time resolution using a streak camera. From the theoretical fitting of photoluminescence spectra we determine the time evolution of the carrier density and carrier temperature. We find the carrier-energy-loss rate to be slower than predicted from a simple model if we assume a Maxwell-Boltzmann distribution function. This is attributed to the screening of the hot-carrier energy relaxation under high-carrier densities. Integro-differential equations describing the time dependence of the carrier temperature are solved, and the results are compared with the experimental data.