Thin films of CuInSe2 produced by rf sputtering with intentional oxygen doping

Abstract

Structural, electrical, and optical properties of CuInSe2 thin films produced by rf sputtering from a stoichiometric target in an Ar/O2 atmosphere are presented. The growth rate decreases rapidly with increasing constituent gas ratio [O2]/([Ar]+[O2]). From x-ray diffraction, Auger electron spectroscopy, and x-ray photoelectron spectroscopy, it can be seen that CuInSe2 and In2O3 are mixed in the thin films for [O2]/([Ar]+[O2])≳3%. SeO2, CuO, and In2O3 coexist together at the surface of these thin films. Hot probe analyses indicate that these thin films show n-type conduction. The Van der Pauw measurements and the optical transmittance measurements show that the resistivity decreases and the band gap increases with an increase in the [O2]/([Ar]+[O2]) ratio.