Impurity conductivity in low compensated semiconductors

A theory of the temperature and concentration dependence of the impurity conduction in low compensated semiconductors is presented. For the activation energy the expression ε₃ = 0.99 (e²/x)N D1/3 (1 − 0.43 v K^1/4) is derived, where N_D is the majority impurity concentration, K is the degree of compensation, and v is a numerical factor whose value is likely to be about 0.7. This expression essentially differs from the well known result of Miller and Abrahams. It is shown that the above dependence isin good agreement with available experimental data.