Surface passivation of nano-textured silicon solar cells by atomic layer deposited Al₂O₃ films

In the work, the surface recombination of silicon nanostructures was investigated. Silicon nanostructures were synthesized using technique of silver catalyzed chemical wet etching, and the passivation layers of SiN_x and Al₂O₃ were deposited on the samples. The thermal atomic layer deposited Al₂O₃ can conformally cover the rough surface and reduce the defect density of the nanostructures. Moreover, the negative fixed charge in Al₂O₃ layer introduces the surface field effect passivation. The lifetime measurement result indicates that Al₂O₃ layers offer much better passivation effect on the silicon nanostructure surface than SiN_x layers. The silicon nano-textured solar cells with SiN_x and Al₂O₃ passivation layers were manufactured and measured. The results show that the enhanced solar cell performance was achieved by Al₂O₃ passivation.