Hot electron relaxation in In0.53Ga0.47As

We have determined the hot carrier energy loss rate to the lattice by measuring the cooling curve of a photoexcited hot plasma in In_0.53Ga_0.47As. These measurements were made by using a sensitive upconversion technique to measure the infrared (1.2?1.6 μm) luminescence with 10 ps 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.