Carrier-carrier scattering: An experimental comparison of bulk GaAs and GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wells

The energy loss of a hot electron to a thermalized electron-hole plasma has been studied using the optical recombination of a hot electron at a neutral acceptor. The dependence of the energy-loss rate on plasma density was measured in both bulk and quantum-well samples. In bulk, the energy-loss rate is significantly sublinear as a result of screening. In quantum wells, the rate is nearly linear in plasma density, showing that screening is less important. Measurements in an asymmetric coupled-well sample show that the interaction between a hot electron in one well and a plasma in an adjacent well is much weaker than if they are in the same well.