Characterization of selective-emitter solar cells consists of laser opened window and subsequently screen-printed electrodes

Selective emitter technique is still an interesting research subject and attracts many attentions in photovoltaic industry. A selective emitter is a doping layer that is heavily doped underneath the electrode while lightly doped in between the electrode grids. It offers good short-wavelength response due to low surface doping concentration and in the mean time maintains low contact resistance. To successfully incorporate the selective-emitter technique into production, one of the requirements for a cost-effective selective emitter is that the efficiency should be increased significantly compare to those conventional solar cells with uniform doped emitter. However, the developments of commercial Ag-pastes, which are suitable for high sheet-resistance silicon, make uniform lightly-doped solar cell possible. In other words, the successfully developed Ag-pastes may limit the demand of selective-emitter techniques. In this study, we try to demonstrate that the selective-emitter is still an attractive technique even in light/light sheet-resistance combination. In comparison to solar cells with uniform lightly-doped 65 Ohm/sq emitter, the results show an efficiency improvement of more than 0.5% absolute can be achieved for selective-emitter solar cells. The process sequence of the selective emitters in this work includes a laser opening through the oxide mask. It was followed by conventional POCl3 diffusion and a subsequent electrode screen printing.