Hydrogenation Strategy for Al2O3/MoOx Passivating Contact in High-Efficiency Crystalline Silicon Solar Cells

Abstract

Enhancing carrier selectivity and minimizing surface recombination are crucial factors for improving the efficiency of passivating contact crystalline silicon (c-Si) solar cells. This study introduces a two-step hydrogenation method, using atomic layer deposition of Al₂O₃ and forming gas annealing (FGA), in order to optimize the passivating contact stack. This approach not only improves the passivation quality but also reduces the contact resistance in the presence of a MoO_x transport layer. However, excess hydrogen in Al₂O₃ could potentially diffuse into MoO_x, reducing its work function and diminishing the field-effect passivation. By fine-tuning the FGA parameters, including temperature and duration, a conversion efficiency of 21.33% is achieved on p-type silicon. These results demonstrate a novel optimization strategy for passivation tunneling layers, with the potential to improve the performance of c-Si and other types of solar cells.