Improvement of the path-integral approach to heavily doped semiconductors

Abstract

The heavily doped semiconductor is modelled as a system of an electron moving in a large number of dense and weak impurities, or in a Gaussian distributed potential. Both Gaussian and screened Coulomb potentials are considered. The improved path-integral approach, using the two-parameter variational method, is applied to find the density of states. The full-ground-state and deep-tail approximations are used to obtain the expressions for the density of states in closed forms, similar to those obtained by the one parameter theory and Halperin and Lax' method. To evaluate the parameter values, two variational principles are taking into account. Numerical results are presented and compared with those of others