Hot carrier cooling in gaas quantum wells

The cooling of a hot electron-hole plasma in undoped, p-doped, and n-doped GaAs/AlGaAs quantum wells of three different thicknesses (3, 9, and 20 nm) is investigated by picosecond luminescence spectroscopy. The energy loss of holes due to the Fröhlich interaction is at low excitation densities independent of well width and close to the value obtained by a simple theory. The rate strongly decreases with increasing excitation density. For electrons, the energy loss is even at low densities strongly reduced compared to the simple theory of the Fröhlich interaction. The reduction of the energy loss at high densities is independent of dimensionality and well width and not caused by screening or degeneracy effects. The energy loss due to acoustic deformation potential scattering depends on well width.