Hot-electron cooling and second-generation phonons in polar semiconductors

The acoustic-phonon bottleneck is studied theoretically within the model which includes Fro{}hlich interaction between electrons and LO phonons, and anharmonic coupling between the LO phonons and second-generation acoustic phonons, in the form of the Klemens interaction operator. Calculations are performed for bulk CdSe and GaAs. The acoustic-phonon bottleneck effect is shown to depend on the amount of energy provided by the laser pulse. The lifetime of the hot-electron cooling in the regime of the acoustic-phonon bottleneck appears to be controlled by the highly efficient channel of the fusion of acoustic phonons into LO phonons.