Optimization of nanohole array parameters for improving the ultimate efficiency of nanohole structured c-Si solar cells

Abstract

Surface texturing helps in reducing the reflectance of the surface and hence it improves the ultimate efficiency of the solar cell. In this article, rigorous coupled wave analysis was used to find out the effect of different nanohole parameters such as nanohole diameter (D), pitch (P) and nanohole depth (H) on the reflectance and the ultimate efficiency of a c-Si solar cell of 275 μm thickness. Response surface methodology was used for co-relating the nanohole geometry parameters with the ultimate efficiency. The developed relation was used for optimization using genetic algorithm implemented through MATLAB. The optimized parameters have resulted in a 17.81% improvement in ultimate efficiency as compared with bare substrate of same thickness. A comparative study was made on the effect of parameters on the ultimate efficiency of the solar cell and it was found that higher value of diameter yielded greater ultimate efficiency. Finally, the performance of structured Si was compared with that of bare Si and Si coated with anti-reflective coating in various configurations. A 50 nm deep hole filled with anti-reflective coating and with a top surface anti-reflective coating of 75 nm yielded the highest ultimate efficiency of 47.61%.