Propagation of Large-Wave-Vector Acoustic Phonons in Semiconductors

Abstract
The spatial and temporal characteristics of phonon pulses generated in the interband energy relaxation process of photoexcited eh pairs in GaAs and InP are reported. With use of a superconducting Pb tunnel junction as a phonon threshold detector, it is shown that the energy transport occurs via near-zone-edge transverse acoustic phonons and that over lengths of the order of several millimeters the pulse propagation shows all features of ballistic transport in a dispersive medium.