Novel thin-film CuInSe2 fabrication

This report describes work to study the feasibility of fabricating CuInSe2 (CIS), to be used in photovoltaic cells, by rapid annealing processes including laser processing and rapid thermal processing (RTP). Presently, the chalcopyrite phase of CIS is obtained by thermally annealing elemental Cu and In layers in H2Se gas. This process is hazardous because of the high toxicity of the hydrogen selenide gas, making the process unattractive for large-scale production. The ability to form the desired chalcopyrite structure with favorable optical and electrical properties by rapid annealing processes would be safer and more conducive to large-scale production. Initial studies of the feasibility of laser annealing the elemental layered structures have been performed using CW argon and Nd:Yag lasers on films fabricated by thermal resistance evaporation in a vacuum of 10(exp -6) torr. Characterization of the post- annealed films by x ray diffraction analysis has shown encouraging results. The laser annealed films have all contained the chalcopyrite phase of CIS, although the percentage of the chalcopyrite phase has been small. Undesirable binary compounds have also formed. To produce higher-quality films, future work will concentrate on increasing the percentage of the desirable phase and eliminating all binary compounds.