Optical determination of phase composition and processing effects on Cu2ZnSnSe4 film quality and device performance

摘要

Cu2ZnSnSe4 has shown promise as a potential follow-on for CIGS because of the replacement of In with earth abundant Zn and Sn. At this early stage of development and because of its complexity little is known about its fundamental properties. The band gap in particular seems to vary even for the same film composition. In this paper we present an optical model that can be used to correlate optical properties with composition and structure. The model is enabling the determination of phase composition which is not easily done with normal techniques such as XRD. We also discuss our 2SSS processing approach and issues related to the eventual manufacturabilty of this technology.