Analysis of thin-film silicon solar cells with plasma textured front surface and multi-layer porous silicon back reflector

The optical performance of thin crystalline silicon solar cells with plasma textured front surface and with porous silicon stack back reflector is analysed. A rigorous analytical ray tracing model, that uses an accurately estimated porous silicon refractive index, is elaborated to predict the optical absorption, carrier generation, external quantum efficiency, and total photogenerated current in the cell. Calculated results best fitted to those measured for an experimental demonstration cell show that surface recombination is a major loss factor in the demonstration cell. The study also concludes that the plasma textured front surface has poor light diffusion properties, and predicts that the maximum gain in the photocurrent from back reflection at the porous silicon stack equals 10% compared to 20% if the back reflector is ideal. However, the proposed cell is realistic and promises excellent performance when state of the art front surface texturing, passivation and front metallization techniques are implemented.