The Effects of Porous Silicon and Silicon Nitride Treatments on the Electronic Qualities of Multicrystalline Silicon for Solar Cell Applications

This work used plasma-enhanced chemical vapor deposition (PECVD) at low temperatures to deposit a silicon nitride layer on multicrystalline silicon (mc-Si), both with and without porous silicon, in an attempt to enhance the multicrystalline silicon's properties for solar cell applications. Silicon nitride has been successfully tested as a passivation and antireflection film in mc-Si. Consequently, reflectance is reduced from 40 to 7% in the 300-1200 nm wavelength range due to the change in the silicon's morphology, while the effective carrier lifetime value for the Si substrate rose from 8 mu s to 71 mu s following SiNx treatment, thus benefitting a solar cell. A laser beam-induced current (LBIC) also revealed an improvement in the diffusion length of minority carriers, with it rising from 150 mu m to 432 mu m following SiNx treatment. Excellent results were also observed after combining porous silicon with a SiNx thin film, it increased the effective carrier lifetime to 104 mu s, the diffusion length to 676 mu m, the reflectance reduced to 3%, and the surface recombination velocity reduced to 1.6 cm/s. The obtained results therefore suggest that PECVD-based silicon-nitride-covered porous silicon shows promise in terms of cost-effectiveness and efficiency, thus helping to advance solar cell technology.

Automated summary

This study used PECVD to deposit a silicon nitride layer on multicrystalline silicon with and without porous silicon, aiming to enhance its properties for solar cell applications. The results showed that the application of silicon nitride reduced reflectance and improved the carrier lifetime and minority carrier diffusion length. Combining porous silicon with a SiNx thin film further improved the performance.