Enhanced photovoltaic performance of vapor-liquid-solid grown silicon nanowire array with radial heterojunction

摘要

We present the fabrication of a vapor-liquid-solid grown silicon nanowire array solar cell with a radial heterojunction. Lithography defined Cu catalyst patterning is used to grow a periodic array of 300 nm diameter nanowires with a center-to-center distance of 800 nm. A conformal a-Si:H layer is deposited on the nanowire surface to create the heterojunction and passivate the nanowire surface. Transparent conductive oxide and Ni-Al metal grid are then deposited to complete the solar cell fabrication. With a nanowire height of 1.6 μm, the solar cell has an open-circuit voltage of 467 mV. This clear improvement of the open-circuit voltage compared to previous works may be due to the conformal deposition of a-Si:H and to the use of a Cu catalyst. The parameters limiting the solar cell performances are discussed and explained. This work opens up the possibility to fabricate silicon nanowire array solar cells on low-cost substrates.