Impurity-band tails based on semiempirical pseudopotentials in heavily doped semiconductors

A new approximate method is presented for calculating the one-electron Green's function and the density of states for heavily doped semiconductors. The Green's function which was given by Bonch-Bruevich and by the present author under different approaches is used, but the true impurity potentials are replaced by semiempirical pseudopotentials giving an improved description of impurity-band tails. The theory is tested with the use of experimental data of the density of states in $p$-GaAs, showing considerable good agreement. In contrast, earlier theories turn out not to explain the experiments.