Two Channels of Minority Charge Carriers Recombination in a Homogeneous Semiconductor Target

The process of nonstationary diffusion of nonequilibrium minority charge carriers, which is realized after the termination of the effect of an electron probe on a homogeneous semiconductor target, is considered by mathematical modeling methods. For a low-energy (up to 10 keV) electron probe, a mathematical model of two-dimensional diffusion of charge carriers in a homogeneous semiconductor material is proposed, taking into account the dynamics of changes in target temperature after the termination of electron irradiation of the probe. When calculating the dependence of the density of nonequilibrium minority charge carriers generated by an electron probe on the coordinates, a mathematical model of energy loss by primary electrons was used, taking into account the separate contribution of electrons that experienced small-angle scattering and absorbed into the target and the contribution of backscattered electrons that experienced a small number of scattering at large angles and left the target. The differential equation of thermal conductivity is solved approximately using the projection method. The quantitative description of the temperature dependences of the effective lifetime and the diffusion coefficient of the generated charge carriers was carried out taking into account the available results of experimental electron probe studies of cathodoluminescence of homogeneous monocrystalline gallium nitride. Model calculations have been performed for the diffusion of excitons in homogeneous monocrystalline gallium nitride in the presence of two independent recombination channels of nonequilibrium charge carriers.