Photoluminescence from GaAs quantum wells under high electric fields.

The room temperature photoluminescence spectra of n-modulation doped GaAs-AlGaAs multiple quantum wells have been studied at high electric fields in order to obtain the distribution function of the two-dimensional electron system under high field conditions. The spectra show thermalized energy distributions with electron temperatures of ~600K in the range where current instabilities indicate negative differential conductivity. This temperature is well below the value expected for bulk GaAs, and can be understood on the basis of real-space transfer of hot electrons into AlGaAs.