Composition and structural study of solution-processed Zn(S,O,OH) thin films grown using H2O2 based deposition route

• Published in: Thin solid films 2013-05, Vol.535, p.171-174
• Main Authors: Buffière, M., Gautron, E., Hildebrandt, T., Harel, S., Guillot-Deudon, C., Arzel, L., Naghavi, N., Barreau, N., Kessler, J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buffer layer; CIGSe; Composition and phase identification; Condensed Matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Energy; Exact sciences and technology; Materials Science; Natural energy; Photovoltaic conversion; Physics; Solar cell; Solar cells. Photoelectrochemical cells; Solar energy; Solution processed Zn(S,O,OH); Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.10.029

Recent results have revealed that the low deposition time issue of chemical bath deposited (CBD) Zn(S,O,OH) buffer layer used in Cu(In,Ga)Se2 (CIGSe) solar cells could be resolved using H2O2 as an additive in the chemical bath solution. Although the use of this additive does not hinder the electrical properties of the resulting Zn(S,O,OH)-buffered CIGSe solar cells, the impact of H2O2 on the Zn(S,O,OH) properties remains unclear. The present contribution aims at determining the chemical composition and the microstructure of Zn(S,O,OH) film deposited by CBD using the alternative deposition bath containing the standard zinc sulfate, thiourea, ammonia but also H2O2 additive. Both X-ray photoemission spectroscopy and energy dispersive X-ray spectroscopy analyses reveal higher sulfur content in alternatively deposited Zn(S,O,OH), since the first step growth of the layer. According to transmission electron microscopy analyses, another consequence of the higher deposition rate achieved when adding H2O2 in the bath is the modification of the absorber/buffer interface. This could be explained by the enhancement of the cluster growth mechanism of the layer. ► The Zn(S,O,OH) layer composition can vary with the chemical bath process used. ► The alternative process leads to a faster incorporation of sulfur in the layer. ► No ZnS epitaxial layer has been found at absorber/alternative buffer interface. ► The use of H2O2 enhances the cluster-by-cluster growth mechanism.