Surface nanostructured high efficiency vertical wire-based solar cell

In this paper, high efficiency surface nanostructured vertical wire-based solar cell is reported. The structural parameters of silicon nanopillar (SiNP) array are investigated through simulation for optimum light absorption. It is found that the ultimate efficiency reaches the maximum 27% at array periodicity 500 nm and SiNP diameter 250 nm. Device physics modeling is also studied. The power conversion efficiency (PCE) of ~18.1% is predicted for cell configuration of 1000 nm height SiNP array (array periodicity: 500 nm; SiNP diameter: 250 nm) on 800 nm thick underlying Si film, with minority carrier diffusion length (L_n) of ~0.6 μm. It is proposed that low-grade Si with relatively small L_n can be employed for photovoltaic application to lower the production cost and yet achieve high efficiency.