Improved Surface Passivation Using Dual-Layered a-Si:H for Silicon Heterojunction Solar Cells

Silicon heterojunction solar cells require high quality surface passivation to enhance the device performance. In this study, dual-layered hydrogenated amorphous silicon (a-Si:H) deposited at different hydrogen dilution is investigated for the improvement of surface passivation. Dual-layered a-Si:H is functionalized as smooth interfacial and dense capping layers. As-deposited dual-layered passivation shows 33.4% enhancement of the minority carrier lifetime from quasi-steady-state photo-conductance measurements up to 197.6 μs comparing to 148.1 μs of single-layered a-Si:H at 1015 cm−3 injection level. The improved effective lifetime and implied open circuit voltage of dual-layered passivation are 401.5 μs and 712 mV with post-annealing process.