EVALUATION AND CHARACTERIZATION OF POLYCRYSTALLINE CUINSE2 THIN-FILMSPREPARED BY THE SANDWICH STRUCTURE TECHNIQUE

The optical and electrical properties of CuInSe2 (cis) have shown it t o be a promising photovoltaic material. The preparation of CuInSe2 thi n films by means of the stacked elemental layer (SEL) technique was de veloped at Newcastle Photovoltaic Centre, Northumbria University. The method is presented as a low-cost technology because of its ability to retain stoichiometry and its scalability for large-area device applic ations. This paper presents a modification of the technique employed t o produce CuInSe, thin films and describes the structure, optical and electrical properties of such films. X-ray diffraction examination, en ergy dispersive x-ray analysis and measurements of the optical transmi ssion and reflection and resistivity were used to determine the film p roperties relative to the preparation parameters and stoichiometry. Th e growth conditions were optimized for solar cell applications. Electr ical resistivities in the range 10(-2) to 10(5) OMEGA cm, energy gaps between 0.96 and 1.03 eV, and an absorption coefficient close to 10(5) for the cis films were obtained in this work.