STRUCTURAL-PROPERTIES OF CUINXGA1-XSE2 THIN-FILMS PREPARED BY RF-SPUTTERING

Cu-In-Ga-Se alloy thin films were prepared by rf sputtering from powder targets previously synthesized by reacting Cu, In, Ga, and Se in the various ratios. From x-ray diffraction analyses, these thin films have chalcopyrite structure of CuInxGa1-xSe2, and the lattice parameters (a and c) are varied linearly with indium content x in the thin films from CuInSe2 to CuGaSe2. The preferred orientation factor f(112) in these thin films was estimated. Its value was always more than 0.79, specifically 0.96 in a CuInSe2 thin films. From scanning electron microscope images, the grain sizes in these thin films decrease with the decrease of indium content. From x-ray photoelectron spectroscopy analyses, the binding energies of the Se 3d, In 3d5/2, Cu 2p3/2 and Ga 2p3/2 in these thin films shifts to higher energies with decreasing indium content, where a slight bowing behavior is observed.