Preparation and characterization of pulsed laser deposited Sb 2 Te 3 back contact for CdTe thin film solar cell

Abstract A low electric resistive and stable ohmic back contact are crucial to the commercial application of CdTe solar cells. In this study the Sb 2 Te 3 thin film is employed as a buffer layer in the back contact of CdTe solar cells. The Sb 2 Te 3 thin films are deposited at different substrate temperature by pulsed laser deposition and then characterized to investigate the thin film properties, firstly. Hall measurements shows the Sb 2 Te 3 thin film presents strong p-type semiconductor features with high Hall mobility and carrier concentration. CdTe solar cells with Sb 2 Te 3 buffer layer in different layer thickness and deposition temperature are fabricated to obtain the optimal experiment conditions for device performance. The dark J-V curve of CdTe solar cell with Sb 2 Te 3 buffer layer exhibits a typical diode curve without roll-over phenomenon. An insertion of Sb 2 Te 3 buffer layer eliminates the Schottky barrier resulting in remarkable enhancement of open circuit voltage, short-circuit current and fill factor. Besides, the external quantum efficiency gets improvement in almost all of the absorber wavelength compared to the cells with Au-only contact.