Growth of Cu In1-x Alx Se2 Thin Films by Selenization of Metallic Precursors in Se Vapor

The wide band-gap CuIn1-xAxlSe2(CIAS) films were obtained by selenization process of metallic precursors. The metallic precursors were deposited sequentially by using sputtering system. As the ratio of Al/(Al+In) in the precursors increased, the chalcopyrite (112) peak shifted to high value and the band-gap of CIAS layer increased to 1.38 eV. However the bi-layer morphology with well crystallized large grain on the surface and small grain thin bottom layer was observed. Although the sequences of precursors were changed in order to get uniform layer, the distinguishable difference was not observed. Moreover the films were peeled off completely during the deposition of buffer CdS. The other process conditions such as selenizing at high temperatures, Se containing precursors and post annealing will be tried to remove the bi layer and to get homogeneous films.