Nonequilibrium electron-hole-plasma in GaAs quantum wells.

We demonstrate the existence of a nonequilibrium electron-hole- plasma in the semiconductor GaAs under the influence of high electric fields. Injected minority electrons are observed to be at much higher carrier temperatures than the majority hole plasma. The measurement of the electron energy loss rate under these conditions allows the first determination of the energy transfer by electron-hole Coulomb scattering in a semiconductor.