Validation of analytical modelling of locally contacted solar cells by numerical simulations

We verify a fast and simple analytical model for locally contacted rear surface passivated solar cells by three dimensional numerical simulations. For low level injection conditions the analytical model shows good agreement with the numerical results. For intermediate injection levels and for the injection dependent bulk lifetime in oxygen contaminated silicon, the present analytical model deviates from the numerical results. The accordance clearly improves when including injection dependent recombination and conductance in the analytical model. For intermediate to high injection levels, it is crucial to implement additional corrections for injection effects, being emphasised by the low recombinative front side and bulk material of the device structure investigated in this work. When accounting for these deviations from low level injection, analytical modelling turns out being a fast way to predict the optimum contact spacing as well as the electrical parameters of locally contacted rear surface passivated solar cells even for intermediate injection conditions.