Impacts of n-type interface on the performances of a-Si based solar cells

This paper reports experimental results and numerical simulations for the impact of n-type interface on the performance of n-i-p type a-Si based solar cells deposited on stainless steel (SS) foil substrate. Here the n-type interface includes the interfaces of n-a-Si layer with i-a-Si layer and SS substrate. The obtained results show that 1) the extra interfacial layer between SS and the n-a-Si layer will cause a rollover behavior of the light I-V curve, and H₂ plasma pretreatment on the SS surface may eliminate the extra layer and significantly improve the cell performance; 2) the contamination of n-dopants for the sequential growth of i-layer will seriously deteriorate the cell performances and cause a crossover of the dark and light I-V curves when the n-i-p a-Si solar cells were deposited in a single chamber mode; and 3) the i-a-Si buffer layer between i-a-SiGe and doped a-Si layers could improve the cell performance, but if the thickness of the buffer layer was beyond a critical value, it may cause a bending of the light I-V curves.