Polarization photosensitivity of polycrystalline-film Cu(In,Ga)Se2/CdS/ZnO structures

The photosensitivity of polycrystalline-film Cu(In,Ga)Se-2/CdS/ZnQ solar cells with different thickness of CdS and ZnO films have been studied. These structures exhibit a conversion efficiency 11-12% under illumination of natural radiation in the spectral region from 1.2 to 2.4 eV at temperature T = 300 K. Polarization photosensitivity was observed for oblique incidence of linearly polarized radiation on the ZnO surface of these structures. An induced photopleochroism and an increase of the photocurrents as a result of a decrease of reflection losses were found. The induced photopleochroism coefficient P-I increases with the angle of incidence Theta as P(I)similar to Theta(2) and its value is found to be 10-17% at Theta = 75(0). The results of these polarization investigations demonstrate the sensitivity of the photoelectric processes to the optical quality of the ZnO films. Such polycrystalline-film solar cells can be employed as polarization-photosensitive devices.