Hot electron relaxation in In(0.53)Ga(0.47)As.

We have determined the hot carrier energy loss rate to the lattice by measuring the cooling curve of a photoexcited hot plasma in In(0.53)Ga(0.47)As. These measurements were made by using a sensitive upconversion technique to measure the infrared (~1.2-1.6micron) luminescence with 10 picosecond time resolution. We find the carrier energy loss rate to be about an order of magnitude smaller than predicted by a simple model, and surprisingly insensitive to carrier density at high densities.