Na-incorporatedCu(In1−xGax)3Se5(Cu(In1−xGax)3Se5:Na)films were prepared by the deposition ofCu(In1−xGax)3Se5layers onNa2S-coated substrates. Electrical properties of theCu(In1−xGax)3Se5:Nafilms were evaluated byI–Vand spectral response measurements of devices with anITO/ZnO/CdS/Cu(In1−xGax)3Se5:Na/Mo/glassstructure. TheCu(In1−xGax)3Se5:Nafilms withx>0showedp-type conduction, whereas forCu(In1−xGax)3Se5without the addition ofNa2S,films withx<0.3showedn-type conduction. The addition of Na was found to have a strong influence on the electrical properties ofCu(In1−xGax)3Se5films as well asCu(In1−xGax)Se2films. ©1997 American Institute of Physics.