Dynamics of non-equilibrium short-wave-length phonons in semiconductor heterostructures

The charge carriers heating in the conducting channel of a semiconductor heterostructure device is mainly controlled by the phonon system feedback. The feedback effects, in their turn, are determined by spatial, energy, and modal distributions of the acoustic phonons transferring the excessive lattice energy. In all the existing device-simulation packages, these distributions are characterized by temperature, at most non-local temperature and/or difference between electron and lattice temperatures being taken into account. The energy dissipation from the device operation area is then described by the semiclassical thermoconductivity equations or in the modified framework of nonlocal heat transfer. We show that this approach fails under high rate of phonon generation in the device operation channel. We obtain the spatial and energy distribution of the phonons in steady state, and show their being drastically different from those expected in the thermoconductivity model.