Inhomogeneous Field Distribution in Homogeneous Semiconductors Having an n-Shaped Negative Differential Conductivity

摘要

Layer-like field inhomogeneities in homogeneous semiconductors which have been shown to occur whenever the conductivity decreases faster than linearly with increasing field strength, are discussed using Poission and transport equations including drift and diffusion terms only. Stationary solutions are obtained for differential negative conductivity due to field-dependent carrier concentration or to field-dependent mobility in an approximation neglecting the diffusion term in the transport equation. When the diffusion is included, the method of characteristics is used to compare solutions for the case of field-dependent carrier concentration with the case of field-dependent mobility. A linear analysis of the behavior of solutions near singular points is conducted for more detailed information about the solution near boundaries. (Author)