Performance analysis of vertical multi-junction solar cell with front surface diffusion for high concentration

•The VMJ cells with front surface diffusion were simulated numerically using TCAD software.•The device parameters of the cells were optimized under 1 sun and 1000 suns.•The efficiency of the VMJ cells increased after front surface diffusion.

The vertical multi-junction (VMJ) solar cell has good potential applications in high concentration photovoltaic. The efficiency of VMJ cell reached to 19.19% under 2480 suns has been reported. Numerical calculations show that the efficiency can reach close to 30% after optimization. In this work, the performance of the silicon VMJ cell with front surface diffusion working under 1 sun and 1000 suns was calculated numerically using a TCAD software. The front surface diffusion can reduce the requirement of high quality front surface passivation, but increases the series resistance. The effect of the N-type emitter dopant profile, P+-type back surface field dopant profile, width, thickness, bulk doping concentration and lifetime of the sub-cell on the performance of the VMJ cell with front surface diffusion was calculated and analyzed. The efficiency reached to 30.56% under 1000 suns after optimization.