Significance of the long-range part of the Coulomb potential on the mobility in impure bulk semiconductors

Abstract

We present a new Monte Carlo simulation scheme which explicitly includes the long-range part of the Coulomb potential associated with the electron–impurity interaction and investigate the effects of the long-range part of the Coulomb potential on electron mobility in impure bulk semiconductors. We show that in bulk semiconductors, the long-range part of the Coulomb potential manifests itself as the long-range potential fluctuations and the variance of the potential fluctuations becomes larger as the impurity concentration increases. In high-doped regions with the impurity concentration above 10 16 cm −3, the length-scale of the long-range potential fluctuations becomes comparable with that of electron's mean-free-path. As a result, an electron's trajectory is greatly distorted during the drift motion by the long-range potential fluctuations and, thus, the electron mobility in impure semiconductors is degraded.