CuInS2 sprayed films on different metal oxide underlayers

CuInS2 films as absorbers for solar cells were deposited by the spray pyrolysis method onto commercial ITO and TCO glasses and two different types of TiO2 and ZnO electrodes-flat and porous. Structural, morphological and electrical properties of metal oxide/CuInS2 structures have been studied. CuInS2 crystallite sizes of 6-10 nm on flat electrodes and of 20-30 nm on randomly orientated porous underlayers have been calculated. Doped large band gap oxides are found to be appropriate conductive electrodes for CuInS2 deposited with the spray process. Flat TiO2/CuInS2 and ZnO:In/ZnO/CdS/CuInS2 solar cell structures, entirely prepared by spray technique, show output characteristics of U-OC = 373 mV, j(SC) = 3.5 mA/cm(2) and U-OC = 430 mV, j(SC) = 8.1 mA/cm(2), respectively. The penetration of CuInS2 into microporous and columnar structures has been confirmed by scanning electron microscopy studies. (C) 2003 Elsevier Science B.V. All rights reserved.