Epitaxial Cu(In,Ga)S2 thin film solar cells

Epitaxial layers of the quaternary compound Cu(In,Ga)S-2 and the ternary compound CuInS2 were grown on Si(111) substrates via Molecular Beam Epitaxy. The layers were investigated for their morphological and structural properties using Rutherford backscattering spectroscopy, atomic force microscopy, reflection high-energy electron diffraction and X-Ray diffraction. Furthermore, complete solar cell devices were processed from these layers and their photovoltaic properties were investigated by means of I(U)-curves under illumination. Thus, efficiencies up to eta = 3.2% were achieved. The comparatively low performance of the solar cell devices is attributed to certain heterogeneities of the samples as a result of the growth process. (c) 2005 Elsevier Ltd. All rights reserved.