Electrical and photoluminescence measurements have been carried out onCuInSe2single crystals. The observed temperature dependence of the Hall coefficient inn-typeCuInSe2single crystals is explained in assuming the existence of an impurity band. The values of the activation energy of the shallow donors, their concentration, and the concentration of the compensating acceptors were calculated. The values of the activation energy of the deep donors (80±10 meV and 110±10 meV) were estimated on the basis of the photoluminescence measurements. The concentration dependence of the activation energy of the shallow donor level and the variation of the Coulomb interaction as a function of the carrier density are determined. ©1997 American Institute of Physics.