Immersion of silicon solar cells in an oxidation solution

The conventional wafer-type crystalline silicon solar cells have an approximately 80nm thick top SiNx coating which acts as an anti-reflection layer. The SiNx layer also passivates the silicon substrate surface to reduce free electron consumption very near the surface. Besides, it was known that the properties of the SiNx layer itself may, to some extent, affect the performance of the solar cell. The purpose of this study is to provide a low-temperature method that will help to modify the properties of the SiNx film, especially for low-temperature grown SiNx thin layer. This is achieved by immersing the finished silicon solar cells into an oxidation solution containing strong oxidant. Oxidation solution helps to oxidize the low-temperature grown SiNx as well as the weakly passivated silicon surface. By applying the techniques, the properties of the SiNx layer have been modified and an enhancement on cell performance was demonstrated. The results presented in this study show that the properties of the SiNx layer need to be taken with care, because they may affect the performance of the solar cells.