Growth and Characterization of CIS Thin Films Prepared by Ion Beam Sputtering Deposition

Copper indium diselenide (CuInSe₂) thin films were prepared by ion beam sputtering Cu, In and Se targets continuously on BK7 glass substrates and the three-layer film was then annealed in the same vacuum chamber. X-ray diffraction shows that the CuInSe₂ thin films have a single chalcopyrite structure with preferential (112) orientation. Scanning electron microscopy reveals that the CIS thin films consist of uniform and densely packed grain clusters. Energy dispersive x-ray spectroscopy demonstrates that the elemental composition of CIS films approaches the stochiometric composition ratios of 1:1:2. Raman measurement shows that the main peak is at about 174 cm^-1 and this peak is identified as the A₁ vibrational mode from chalcopyrite ordered CuInSe₂. Optical transmission and absorption spectroscopy measurement reveal an energy band gap of about 1.05 eV and an absorption coefficient of 10⁵ cm^-1. The film resistivity is about 0.01 Ωcm.