Cu(In,Ga)(Se,S)(2)-based solar cells with an alternative ZnSe buffer prepared by an iodine-enhanced low-pressure chemical vapour deposition (CVD) from a powder source were investigated. The application of iodine allowed acceptable transport rates even at substrate temperatures below 300degreesC, which is essential to avoid damage to the predeposited absorber. So far, the most efficient cells provided with a CVD ZnSe buffer yielded efficiencies of more than 80% of reference cells with CdS buffer from a chemical bath. The losses are due to a reduced open circuit voltage and fill factor whereas the short circuit current density was improved as a consequence of less absorption losses in the buffer. The photocurrent was observed to be voltage dependent, which affects open circuit voltage and fill factor. In addition, measurements of the voltage-dependent quantum efficiency as well as the junction capacitance revealed a reduced doping density and an enlarged space charge region of the Cu(In,Ga)(Se,S)(2) absorber in solar cells with a ZnSe buffer prepared by CVD. (C) 2002 Elsevier Science B.V. All rights reserved.