Phase Evolution during Ageing of Co-Electrodeposited Cu–Zn–Sn Thin Films and Effect of Soft Annealing

Electrodeposition of CZT thin films can be a cost-effective and time-efficient process in obtaining CZTS absorber layer to be used in thin film solar cells. The electrodeposited film is composed of atomically mixed elements in different phases involving Cu, Zn and Sn which change significantly over a period of time. The films are characterized using XRD for probing phase evolution and to understand the time required to obtain stable phases. Soft annealing (250 and 350°C) of these films yielded stable phases that would otherwise take longer time intervals when stored at room temperature. Soft annealing followed by sulphurization yielded CZTS thin film with desired properties to be used as absorber material in thin film solar cells.