Real-time investigations on the formation of CuInSe2 thin film solar cell absorbers from electrodeposited precursors

Abstract In this article, we present results of a detailed real-time X-ray diffraction (XRD) study on the formation of CuInSe 2 from electroplated precursors. The solid-state reactions observed during the selenisation of three different types of precursors are presented. The first type of precursors (I) consists of the nanocrystalline phases Cu 2− x Se and InSe at room temperature, which react to CuInSe 2 starting at 470 K. The second type of precursor (II) shows an inhibited CuInSe 2 formation out of the initial phases Cu 2− x Se and γ -In 2 Se 3 starting at 400 K. The third precursor type (III) shows completely different selenisation behaviour. Starting from the intermetallic compound Cu 11 In 9 and amorphous selenium, the formation of the binary selenides In 4 Se 3 and CuSe is observed after the melting point of selenium at 494 K. After selenium transfer reactions, the compound semiconductor CuInSe 2 is formed out of Cu 2− x Se and InSe. This type (III) reaction path is well known for the selenisation of SEL precursors (stacked elemental layers of sputtered copper and indium and thermally evaporated selenium).