Improved PERC Solar Cell Design by TCAD Simulation

In this work, we aim to identify the performance limiting factors and consequently improve the performance of PERC solar cells through extensive TCAD based device simulation and modelling. Initially, a simplified planar PERC solar cell structure is simulated in Silvaco (Athena/Atlas), where the device geometry is selected according to an experimentally fabricated cell with an efficiency of 17.86%. The J-V curves and solar cell parameters such as Jsc, FF, Voc and efficiency (η) of the simulated cell are then fitted to the experimental performance parameters by incorporating relevant models as suggested by the literature. These include: carriers’ generation-recombination, mobility, statistics and bandgap narrowing. A good agreement is obtained, where the average percentage difference between simulated and experimental performance parameters is 0.65%. The solar cell performance is then improved to 21.52% by optimising the anti-reflective coating stack composition and thickness, and adding surface texturing. This increase in efficiency is attributed to lower surface recombination and reduced reflection due to light trapping. In addition, a textured front surface enhances the path-length of light, causing it to undergo multiple internal reflections which further increases light trapping, thus increasing Jsc by 7.31 mA/cm2.