Performance Analysis of Rear Point Contact Solar Cells by Three-Dimensional Numerical Simulation

The adoption of local point contacts at the back surface of high-efficiency monocrystalline silicon solar cells is strategic in order to reduce the recombination losses at the rear side of the device. However, the reduction of the rear-contact surface leads to an increase of series resistance losses. In this paper, we present an extensive analysis based on 3-D optoelectronic numerical device simulations in order to highlight the dependence of the conversion efficiency on the main geometrical and technological parameters of the cell, such as the pitch and the size of the rear point contacts and the substrate resistivity. A state-of-the-art device simulator has been successfully adopted in order to accurately solve the transport equations in the semiconductor by taking into account all the loss mechanisms that are crucial in order to address the design of the cell.