High efficiency n-type silicon solar cells with local back surface fields formed by Laser Chemical Processing

In this work, n-type silicon solar cells with local back surface field (LBSF) formed by Laser Chemical Processing (LCP) is presented. The effect of rear passivation layer and LBSF pitch on the efficiency is investigated. The SiO2/a-Si: H passivated contact is implemented into the n-type solar cells with LCP-LBSF. With the optimal pitch, an average efficiency of 20.4% and 19.8% is achieved on the LCP processed n-type solar cells with SiO2/SiNx stack and single SiNx rear passivation, respectively. Those cells' efficiency is mainly limited by the high surface recombination at the LCP doped regions. With the implementation of the SiO2/a-Si:H passivated contact to the LCP regions, an absolute efficiency gain of up to 1.5% is achieved for the n-type solar cells with SiNx rear passivation. The results show the potential to fabricate high efficiency n-type solar cells with simplified processing by using LCP and the passivated contact concept.