Novel thin-film CuInSe{sub 2} fabrication. Annual subcontract report, 1 March 1990--30 April 1991

This report describes work to form thin films of CuInSe{sub 2} (CIS) by annealing precursor films containing Cu, In, and Se in a rapid thermal processor. This involves two steps: (1) a precursor containing Cu, In, and Se is deposited on unheated substrates such that CIS does not form during this deposition step, and (2) the precursor is annealed in a rapid thermal processor to crystallize the CIS. Advantages of this process are that (1) no H{sub 2}Se is used; (2) concentration gradients can potentially be built into the film due to the rapid anneal; and (3) the precursor can potentially be deposited using scalable methods such as sputtering, solution growth, and electrodeposition. The deposition method used was three-source, elemental physical vapor deposition. At room temperature, such a method was considered to be a flexible way to deposit a precursor that would be fairly typical of precursors deposited by more scalable techniques. Precursors were made both by the stacked elemental layer approach, where one element at a time wsas evaporated, as well as by a co-evaporation method. Adhesion problems limited device performance, and the co-evaporated precursors displayed unintended segregation of Cu and I in a direction normal to the filmmore » plane. The best cell efficiency was 3.5%.« less