Thickness and annealing evolution to physical properties of e-beam evaporated ZnTe thin films as a rear contact for CdTe solar cells

The CdTe solar cell engineering is still lacking maximum achievable power conversion efficiency as predicted based upon the detailed balance. In device development, each constituent layer plays important role and to reduce open-circuit voltage loss, the reduction of back surface recombination is a promising approach. It could be made by introducing a wide-band gap ZnTe layer between the absorber CdTe layer and metal contact which can solve the issue of the Schottky barrier at the interface. The ZnTe layers also need optimization to the physical properties to implicate in CdTe-based device and therefore, the present work reports annealing and thickness evolution to ZnTe films to seek their feasibility as rear contact material where 200 nm and 300 nm thin ZnTe films are developed employing e-beam evaporation and subsequently annealed at 100 °C, 200 °C and 300 °C in air ambient followed by characterizations by amicable tools for exploration of relevant physical properties. Findings demonstrate that the film thickness and annealing temperature have considerably affected the physical properties of the developed films and the 200 nm ZnTe thin films annealed at 100 °C may be implicated as rear contact material in CdTe solar cell devices.