Evolution of phonon nonequilibrium in single-crystal ZnSe at liquid-helium temperatures

摘要

The photoluminescence and nonequilibrium heat transfer observed in ZnSe single crystals grown by the free growth method on an oriented single-crystal ZnSe substrate in a hydrogen atmosphere were investigated. The nonequilibrium heat transfer (or propagation of nonequilibrium phonons) was studied by the heat pulse method. A region of local thermal equilibrium or "a hot phonon spot" was found to form in the material, and the threshold of its formation was determined. The constant of spontaneous anharmonic phonon decay in ZnSe was estimated from an analysis of the propagation of nonequilibrium phonons via comparison of the experimental responses with those calculated by the Monte Carlo method.