Theory of high-field electronic transport in bulk ZnS and ZnSe

Abstract

We present ensemble Monte Carlo calculations of electron transport in bulk ZnSe and ZnS under conditions of high applied electric field strengths. The calculations include the full details of the first two conduction bands as well as the full‐order treatment of the electron‐phonon scattering mechanisms. The steady‐state electron drift velocities as a function of applied electric field are determined for each material system as well as the total electron‐phonon scattering rates. In addition, the high‐field probability distribution function is presented for both ZnS and ZnSe. As expected, based on the values of the optical‐phonon energy, the electron distribution is much cooler in bulk ZnS than in bulk ZnSe at comparable electric field strengths even in the absence of significant impact ionization in either material. Consequently, carrier heating to comparable energies is more difficult to achieve in ZnS than in ZnSe. This has relevance to the operation of electroluminescent devices made from these materials.