Novel characterization of rear surface passivation effect in thin monocrystalline silicon solar cells by photographic surveying

Reduction of rear surface recombination velocity (S_r) in monocrystalline thin silicon (c-Si) solar cells is important to achieve high conversion efficiency. We propose an evaluation technique of rear passivation effect in thin monocrystalline silicon solar cells by emission microscope. Light emission from the solar cell was detected by a charge coupled device (CCD) camera. We have found that the intensity distribution of light emission correlate closely with the minority carrier density. In thin c-Si solar cells (L>cell thickness), the minority carrier density was affected by S_r, which was estimated from the emission intensity. The passivated and non-passivated rear surface areas were evaluated at the same time, the difference of emission intensity was detected. We considered that distribution of emission intensity showed distribution of S_r.