Influence of the Coulomb gap on the impurity absorption in AIIIBV semiconductors

Using the interpolation formula, which adequately describes the impurity band structure in a broad energy range regardless of the degree of compensation, an explicit expression is obtained for the light absorption coefficient related to the transitions from the impurity band to the conduction band. It is shown that at low temperatures the absorption coefficient has a clearly expressed absorption threshold. The explicit frequency dependence of the absorption coefficient is derived for a wide frequency range of the incident radiation. The absorption coefficient dependence on the degree of doping of a semiconductor is also studied.