Towards optimization and understanding of the photoelectronic properties in CuGaSe₂

The photoconductivity and the minority-carrier diffusion length of CuGaSe₂ were studied in the photocarrier grating configuration. In order to shed some light on the carrier recombination processes, both He-Ne and Ar-laser illuminations were used and the light was applied either to the substrate surface or to the free surface of the films. The substantial variation of the photoelectronic properties along the film growth axis, and their dependence on the light wavelength, are interpreted in terms of the polycrystalline nature of the films. It is suggested that by properly combining deposition conditions and composition one can get a significant improvement in the phototransport properties of these materials.