Improvement of Cu2ZnSnS4 thin film properties by a modified sulfurization process

• DOI: 10.1016/j.tsf.2015.05.060
• Publication Date: 2015-05-30T08:47:57Z
• Authors: Dongwan Seo; Jihoon Na; Changheon Kim; Chaehwan Jeong; Sangwoo Lim
• Keywords: Kesterite; Thin layers

Abstract In the solution-based preparation of CZTS (Cu 2 ZnSnS 4 ) thin films followed by a sulfurization process, a layer of MoS 2 is formed at the CZTS–Mo interface. Formation of this MoS 2 layer is mainly governed by the sulfurization process in H 2 S ambient gas rather than diffusion of a sulfur source in the CZTS film. Growth of CZTS grain and grain boundaries facilitates the formation of a MoS 2 layer in any sulfurization process. A decrease in the series resistance and an increase in the current density and solar cell efficiency were achieved through an increase in the temperature of the second sulfurization sequence in a two-step sulfurization sequence. The formation of a CZTS grain dominates the performance of CZTS thin film solar cells with a relatively thin MoS 2 layer, but the performance is degraded by an increase in recombination rate and the hole barrier effect between CZTS and Mo when the MoS 2 is sufficiently thick.