Optimization of the back surface structure of a crystalline silicon solar cell by using a simulation method

The back surface passivation, including the formation of the local contact through the dielectric passivation layer, is regarded as one of the core technologies for enhancing the efficiencies of crystalline silicon solar cells. In this study, the effects of the rear local contact structure on the performances of the cell were simulated by varying the size of the contact area and the distance between the contacts. Because of the symmetry of the current flow in the cell, a simulation domain was defined, and the geometric parameters, such as the rear contact width and the rear contact pitch, were optimized for a high-efficiency solar cell. The behaviors of the cell’s output parameters also depended on the local doping concentration at the rear local contact. The influence of the rear surface recombination velocity on the efficiency of the cell was confirmed by comparing it with the simplified analytic equation for the short circuit-current density in the solar cell.