Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster: Trends in Ion Beam Technology, Magnetism in Thin Films, Functional Oxides, High-k Dielectric Materials, Semiconductor Nanophotonics, Nanoengineered Thin Films, Layer Deposition Processes, Layer Growth, Layer Properties, Thin Film Characterisation, Metal and Amorphous Layers, Application of Thin Films

DS 17.31: Poster

Dienstag, 26. Februar 2008, 09:30–13:30, Poster A

Sputter deposition of CuS_1−x O_x thin films using ceramic targets — •Swen Graubner, Angelika Polity, Detlef Hofmann, and Bruno K. Meyer — IPI Justus-Liebig-Universität Giessen

The efficiency of CuO solar cells can be estimated up to 30%, although the band gap of CuO is about 0.4 to 1.0 eV too large compared to the ideal band gap of about 1.5 eV. Substitution of oxygen by sulphur may lead to CuS_1−xO_x compounds with reduced band gap and might thus have higher efficiencies. The sputter deposition offers several ways for the preparation of CuS_1−x O_x thin films: the most common one is to use a metallic Cu target and reactive gases like H₂S and O₂. An alternative is the usage of a sintered (ceramic) Cu₂S target with O₂ as reactive sputtering gas. We concentrated on the later, which has the potential to provide higher sulphur concentrations in the films. The thin films were sputtered under various conditions of the substrate temperature and process pressure. To analyze the morphology, the films were investigated by x-ray diffraction (XRD) and electron microscopy. Secondary ion mass spectroscopy (SIMS) and energy dispersive x-rays (EDX) gave information about the stoichiometry of the layers. The band gap properties as a function of the sulphur content were determined by optical absorption measurements, and temperature dependent Hall-effect was measured to determine the carrier concentration and the mobility.