Effects of a defected GaP/Si interface on a Si heterojunction interdigitated back contact (IBC) solar cell

The current record Si heterojunction interdigitated back contact (SHJ-IBC) solar cell uses a thin a-Si layer for front passivation. With the anti-reflective coating removed, and the front a-Si layer replaced by a GaP, it can serve as a bottom cell for a monolithic III-V/Si tandem. However, a GaP/Si interface may have a high density of midgap states. Here we treat the midgap states as single-level acceptor-like and donor-like midgap traps, and investigate the impact of the traps on the IBC performance, and the potential role that a front surface field can play in passivating the two types of traps, using numerical simulation.