Cd‐free Cu(In,Ga)Se₂/In₂S₃ thin‐film heterostructures

Abstract

The technology of heat treatment of initial Cu‐In‐Ga layers in an inert N2 atmosphere in the presence of Se and S vapors was used in self‐organized growth of homogeneous films of Cu(In,Ga)(S,Se)2 alloys onto which the CdS or In2S3 films were deposited and, on the basis of these structures, thin‐film glass/Mo/p‐Cu(In,Ga)(S,Se)2/(In2S3, CdS)/n‐ZnO/Ni‐Al heterostructures were created. The mechanism of charge transport and the processes of photosensitivity in the obtained structures subjected to irradiation with natural and linearly polarized light are discussed. The broadband photosensitivity of thin‐film heterostructures and induced photopleochroism were detected. These findings indicate that there is an interference antireflection of the structures obtained. It is established that higher solar‐cell efficiency in these heterostructures occurs if In2S3 thin films are used as heterobarriers. This technology can be used in the creation ecologically safe Cd‐free next generation thin‐film solar cells. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)