ENERGY RELAXATION OF HOT-ELECTRONS IN A QUANTUM-WELL - CONFINED OPTICAL AND ACOUSTIC-PHONON EFFECTS

Energy-loss rates of hot electrons are calculated for a semiconductor quantum well (QW) of the GaAs/AlGaAs prototype. Couplings with acoustic phonons (AP) and with confined polar-optical phonons (OP) are considered. Hot electrons are assumed in internal equilibrium at a temperature T-e (the temperature model). Comparison with previous calculations of other authors shows that OP confinement with the proper dispersion relation is of utmost importance for the correct interpretation of energy-loss rates in the temperature range of 25 to 100 K. In the lower temperature regime the coupling with AP cannot be neglected. Thus reasonable agreement with experimental data is obtained even within the relatively simple model for the calculation when both mechanisms are taken into account. Other effects (hot phonons, etc.) are not considered and also no fitting parameters of any kind are introduced.