Relaxation of highly excited carriers in wide-gap semiconductors

The electron energy relaxation in semiconductors and insulators after high-level external excitation is analysed by a semi-classical approach based on a kinetic equation of the Boltzmann type. We show that the non-equilibrium distributions of electrons and holes have a customary Fermi-like shape with some effective temperature but also possess a high-energy non-Fermian 'tail'. The latter may extend deep into the conduction and valence bands while the Fermi-like component is localized within a small energy range just above the edge of the band gap. The effective temperature, effective chemical potential, and the shape of the high-energy component are governed by the process of electron–phonon interactions as well as by the rates of carrier generation and inter-band radiative recombination.VGT acknowledges the Tomsk State University Competitiveness Improvement Program and Ministry of Education of Russia base part 101. VPZ acknowledges also the computer facilities (UMT cluster) provided by the Institute of Mathematics and Mechanics of the Ural Branch of The Russian Academy of Sciences and financial support via the project Nos. 12-U-3-1001, 12-U-3-1009 provided by the Presidium of the Ural Branch.Peer Reviewe