Evaluation of recombination velocity at grain boundaries in poly-Si solar cells with laser beam induced current

The temperature dependences of minority-carrier diffusion length and interface recombination velocity at grain boundaries in polycrystalline silicon solar cells have been measured by the scanned laser beam induced current technique in the temperature range from 20degreesC to 100degreesC. Changes of the physical-properties values by the gettering were evaluated. The diffusion length increased with increasing temperature. On the basis of evaluated the diffusion length, the boundary recombination velocity was obtained using Zook's evaluation scheme. The boundary recombination velocity decreased with increasing temperature. The diffusion length and the boundary recombination velocity were improved by gettering in the temperature range from 20degreesC to 100degreesC. Therefore, gettering is effective in the main operating temperature range (20similar to60degreesC) for solar cells in Japan.