Optimisation of emitter properties for silicon heterojunction solar cell ITO/p-a-Si:H/i-a-Si:H/n-c-Si/BSF/Al

Abstract

In this study, the performance of silicon Heterojunction with Intrinsic Thin layer (HIT) solar cell was numerically simulated and optimized by Amorphous Semiconductor Device Modelling Program (ASDMP). In this work we have not only studied the influence of physical and geometric parameters of the emitter on the performance of the cell, we have also studied the conduction and recombination phenomena which are the basis of the improvement / deterioration of the studied solar cell.we were able to conclude that a compromise must be made in the choice of the thickness of the emitter: Not too thin to have a sufficient electric field at the junction p-a-Si: H / n-c-Si, and not too thick, so that a maximum of photons are transmitted to the active layer, and so that the diffusion length of the charge carriers is at least equal to the thickness of the emitter. A thickness of the p-Si: H layer of 155A° has achieved the best values of the cell parameters, with an efficiency of 18.25 %.The performance of the HIT studied cell is improved by increasing the doping density of the emitter layer made of p-type hydrogenated amorphous silicon (p-a-Si: H). Despite the deterioration of the material by the doping, the rate of recombination decreases on the active layer (n-c-Si) because of the higher electric field strength. We achieved an efficiency of 19.8 % by optimizing both of gap energy and doping density.