Photovoltaic Performances of Three-dimensional Architecture Si Radial P-I-N Junction Nanowire Arrays

Two different approaches to realize high-performance silicon nanowire solar cell on low-cost substrates will be presented. Study on Si nanopillars fabricated by deep reactive ion etching followed by epitaxial growth of electrically doped radial shell showed morphological effect on optical absorption, geometrical effect on external quantum efficiency and on device efficiency. Especially optical absorption properties of Si radial p-i-n junction arrays were investigated by both theoretical calculation with finite domain time difference method and absorbance measurements. Photovoltaic cell based on single crystalline Si nanopillar arrays demonstrated efficiency of higher than 10%. Additionally, randomly oriented Si radial p-i-n junction arrays were grown on stainless steel substrate. Si radial p-i-n junction photovoltaic device showed >3.5% efficiency.