Effect of Process Temperature and Copper Doping on the Performance of ZnTe:Cu Back Contacts in CdTe Photovoltaics

CdTe photovoltaic devices with a ZnTe back contact have the potential to improve device performance and stability. After performing a sweep of ZnTe deposition and annealing temperatures, device performances were evaluated. Copper doping was performed after the ZnTe depositions by sublimating CuCl. Initial results indicate that ZnTe deposited and annealed for 20 minutes at 250°C improved device performance in terms of fill factor, JSC, and VOC as compared to other deposition temperatures. Copper doping also impacted device performance and a longer copper treatment on ZnTe led to a 17.6% device.