685-MV OPEN-CIRCUIT VOLTAGE LASER GROOVED SILICON SOLAR-CELL

The recombination limiting the voltage of the present buried contact solar cell (BCSC) can be reduced by replacing the present high recombination sintered aluminium back with a floating rear junction for passivation, heavy boron diffusion below the rear contact, and by limiting the rear surface contact area. Analysis of these implementations in the double sided laser grooved (DSLG) structure shows that the floating junction passivation is effective in reducing the recombination component at the rear surface and that the boron diffusion in the rear groove comprises up to half of the total saturation current. Limiting the area of the heavily diffused boron grooves allows open-circuit voltages of 685 mV while maintaining the simplicity of the BCSC processing sequence. An open-circuit voltage of 685 mV represents nearly a 50 mV increase over the conventional BCSC.