Formation of polycrystalline thin films of CuInS2 by a two step process

CuInS2 thin films have been prepared using a two-step process. This involve d the deposition of approximately 1700 alternate layers of Cu and In onto m olydenum coated glass substrates using magnetron sputtering followed by an anneal in an environment containing elemental sulphur to synthesise the com pound. This process results in a Cu11In9 precursor phase free from inhomoge neous secondary phases and the synthesis of the compound using elemental su lphur. This method results in densely packed, randomly orientated polycryst alline layers with the chalcopyrite crystal structure with as-synthesised g rain sizes greater than 0.75 mu m for 1 mu m thick layers. Optical data obt ained for these layers indicate a direct energy band gap of 1.45 eV. This i s the first time that CuInS2 layers have been produced by suphurising magne tron sputtered multiple Cu-In multilayers using elemental sulphur. (C) 1999 Elsevier Science B.V. All rights reserved.