Picosecond luminescence study of Hot Carrier Relaxation in 1.3micron In(0.72) Ga(0.28) As(0.6) P(0.4).

We report measurements of luminescence spectra of InGaAsP with 10 psec time resolution and a wide dynamic range. The spectra are dominated by band-to-band recombination processes. Analyses of the high energy tails of the spectra allow a determination of carrier temperatures. From the measured variation of carrier temperatures with time, we show that the carrier energy loss rates to the lattice depend on excitation intensity and are lower than expected on the basis of a model that takes into account the four optical phonon branches in this semiconductor.