Improvement of multi-crystalline silicon solar cell fabricated by laser doping technique using continuous wave laser

Laser doping (LD) has a lot of advantages for low cost processing and achieving high efficiency crystalline silicon solar cells. This method can operate in the atmosphere and at the room temperature. Thus, LD has much attention as an alternative method instead of the conventional thermal diffusion. In this study, we analyzed multi-crystalline silicon (mc-Si) surface condition and electric property after LD. Moreover, we tried to improve solar cell characteristic. As the result, we confirmed origin of surface roughness after laser doping in silicon. We concluded that origin of surface roughness is PSG on the silicon. And we succeeded to reduce the surface roughness by double laser scan. Finally, we confirmed that the surface roughness caused surface recombination of minority carrier. Therefore, photovoltaic efficiency was increased by improvement of surface roughness.