Laser doping and laser annealing for crystalline silicon solar cells processing
This study aims at investigating laser doping and laser annealing for crystalline silicon solar cells processing. Laser-processed emitters are firstly realized using three lasers and different dopants sources. The lasers are a nanosecond green laser, an excimer laser and a high-frequency ultraviolet laser. As dopants sources we used either phosphosilicate glass, phosphorus and boron-doped silicon nitrides, or phosphorus and boron ion implantation. Efficient phosphorus and boron doping are obtained using any of these laser/sources couple. In particular, low sheet resistances and low emitter saturation current densities are obtained. These laser processes are then applied to selective emitter and boron back-surface-field solar cells. Laser-doped selective emitter solar cells (using phosphosilicate glass as a dopants source) reach 18.3 % efficiency. This represents an overall gain of 0.6 %abs when compared to standard homogeneous emitter. On the other hand, laserannealed boron back-surface-field solar cells (using implanted boron as a dopants source) feature an overall gain of 0.3 %abs when compared to standard aluminium back-surface-field solar cells, thus yielding an efficiency of 16.7 %.