Plasmon-pole Approximation Of Hot Carrier Relaxation In Semiconductor Microstructures

For high carrier densities, the standard single-particle approximation for hot carrier energy relaxation in semiconductors is inadequate due to the presence of many-body interactions. In particular, the electron-phonon energy loss mechanism in polar semiconductors must be augmented to account for many-body interactions leading to changes in both the dynamical polarizability and the phonon spectral density. In this paper, the many-body theory of energy relaxation is applied in the plasmon-pole approximation where the confined phonon modes are those of a rectangular "quantum wire" of polar semiconductor. In this approximation, the renormalized phonon propagator, away from mode crossing, has significant spectral weights at two frequencies: the frequency of the plasmon-like mode and the frequency of the phonon like mode. Using the generalized energy-loss formulation of Das Sarma et al., the power radiated by electrons is determined for the case where the dominant energy-loss mechanism is due to scattering from confined phonons in a rectangular quantum wire of polar semiconductor.