Green-laser-doped selective emitters with separate BBr3 diffusion processes for high-efficiency n-type silicon solar cells

Laser-doped boron selective emitters are an ideal candidate for enabling less emitter recombination, lower contact resistance and better blue response of efficient n-type silicon solar cells. However, the low boron concentration of the borosilicate glasses formed during boron diffusion processes and the implementation of ultraviolet lasers have hindered the commercialization of laser-doped boron selective emitters. In this contribution, separate BBr3 diffusion processes for green-laser-doped selective emitters are demonstrated. Laser doping processes were conducted between (1) borosilicate glass deposition and boron driving in and (2) post-oxidation, achieving the optimized laser doped selective emitter with the R-sheet,R- p+/R-sheet,R- p++ of 95.0 Omega/square/54.3 Omega/square, accompanying with the p(+) profile of N-max < 1.4 x 10(19) cm(-3). By comparison to the homogeneous emitter with sheet resistance of 88.9 Omega/square, J(0e, total) of 45.3 fA/cm(2) and rho(c), metal of 2.9 m Omega/cm(2), the employment of the optimum laser doped selective emitter has resulted in the J(0e), total of 31.1 fA/cm(2) and the rho(c, metal) of 1.0 m Omega/cm(2). Finally, the improvement of simulated V-OC (699.6 mV), FF (81.38%) and efficiency (23.13%) were obtained by using the optimized laser doped SEs, compared with the simulated V-OC (694.5 mV), FF (81.14%) and efficiency (22.89%) of the reference. Separate BBr3 diffusion processes for green-laser-doped selective emitters demonstrate the employment of industrial green laser and boron diffusion furnace, instead of expensive ultraviolet laser and other complex boron resources, indicating a promising potential for industrial feasibility.