Effects of Back Contact Materials on Substrate Configuration CdTe Solar Cells

Substrate configuration CdTe photovoltaics has the potential to provide both a reduction in the production costs and improved power to mass ratio. In this study the effect of copper placement in the cells, sequence of CdCl$_{2}$ treatment, and the effect of back contact material on cell performance was examined. Cells were deposited on a Mo coated conductive substrate, on stainless steel or on TCO coated glass, using RF magnetron sputtering. Three different back contacts were used, copper-gold as used in superstrate configuration cells, Sb$_{2}$Te$_{3}$, and ZnTe:N. Cells were measured using a solar simulator at one sun to obtain current density vs. voltage curves and cell efficiencies. The structure that gave the best performance was stainless steel/Mo/Sb$_{2}$Te$_{3}$/CdTe/CdS/ZnO/ZnO:Al, with the best cell having an efficiency of 5.34{\%}.