Photographic surveying of minority carrier diffusion length in polycrystalline silicon solar cells by electroluminescence

Photographic surveying of the minority carrier diffusion length distribution in polycrystalline silicon solar cells was proposed. Light emission from the cell under the forward bias was captured by a charge coupled device camera. We have found that the intensity distribution of light emission clearly agreed with the mapping of minority carrier diffusion length in polycrystalline silicon active layers. The emission intensity had a one-to-one relationship with the minority carrier diffusion length, which yielded a semiquantitative analysis method of the diffusion length mapping and the detection of the deteriorated areas.