Applied Surface Science, Vol.268, 22-27, 2013
Effects of selenization parameters on growth characteristics of the Cu(In,Ga)Se-2 films deposited by sputtering with a Cu-In-Ga, Cu-In-Ga2Se3, or Cu-Ga-In2Se3 target and a subsequent selenization procedure at 550-700 degrees C
Cu(In,Ga)Se-2 (CIGSe) thin films were prepared by sputtering with a Cu-In-Ga, Cu-In-Ga2Se3, or Cu-Ga-Se2Se3 target and a subsequent selenization procedure at 550-700 degrees C. The utilization of In2Se3 is to avoid the pre-matured formation of CuInSe2, which form easily during selenization when metallic In exists in an as-deposited film. CIGSe films prepared with a Cu-Ga-In2Se3 target had shown the composition uniformity. The variations of microstructure, structure, and electrical properties with selenization temperature for films deposited by a Cu-Ga-In2Se3 target were investigated under a one-step or two-step selenization procedure. Selenization mechanism was proposed and its problems were presented. The influence of crystallinity and thin film microstructure on performance of electrical properties were investigated. CIGSe films sputtered by a Cu-Ga-In2Se3 target after two-step selenization at 600 degrees C showed a good microstructure and high mobility of 106 cm(2) V-1 s(-1), avoided a two-layer structure formation in the CIGSe film, and obtain a better crystallinity because of high solute solubility in the selenium solution during a selenization procedure. (C) 2013 Published by Elsevier B.V.