Effect of applied substrate bias on growth of CdTe film by RF magnetron sputtering

In this study, CdTe thin films were grown by RF magnetron sputtering with substrate bias at floating potential and 0, -10, -20, -30, -40, -50, -100 V. The applied substrate biases affect film morphology, grain size and lattice structure. For films grown with substrate bias at floating potential, 0, -10, -20 V, no in-plane strain was observed in the as-grown film and no voids were found after CdCl₂ treatment. After the CdCl₂ treatment, CdTe film grown with -20 V substrate bias show large grain size and high crystalline quality. The conversion efficiency for cells with such film is 12.68%, with V_oc= 779 mV, J_sc= 22.78 mA/cm² and FF= 71.4%.