Optoelectronic Enhancement of Multicrystalline Silicon via SiNx and H2 Plasma Passivation Using PECVD for Photovoltaic Applications

This study explores advancements in photovoltaic technologies by enhancing the optoelectronic properties and electronic quality of multicrystalline Silicon (mc-Si) through silicon nitride (SiNx) and hydrogen (H2) plasma deposition via Plasma-Enhanced Chemical Vapor Deposition (PECVD). This innovative approach replaces toxic chemical wet processes with H2 plasma and SiNx, promoting environmentally friendly and sustainable energy solutions. Key parameters of silicon solar cells, including effective lifetime (τeff), diffusion length (Ldiff), in addition to the iron concentration ([Fe]), were analyzed before and after this sustainable solution. The results show significant improvements, particularly in the edge region, which initially exhibited low τeff and a high iron concentration. After treatment, τeff and Ldiff increased to 7 μs and 210 μm, respectively, compared to 2 μs and 70 μm for untreated mc-Si. Additionally, the [Fe] decreased significantly after the process, dropping from 60 ppt to 10 ppt in most regions. Furthermore, the treatment led to a significant decrease in reflectivity, from 25% to 8% at a wavelength of 500 nm. These findings highlight the effectiveness of PECVD-SiNx and H2 plasma treatments in improving the optoelectronic performance of mc-Si, making them promising for high-efficiency photovoltaic devices.