Fabrication of PECVD grown n-i-p silicon nanowire solar cells

Abstract

Silicon nanowires have been shown to have strong light trapping properties making them a promising photovoltaic material. In this study, silicon nanowires, grown by RF plasma enhanced chemical vapor deposition (PECVD), are incorporated as the absorbing layer in n-i-p solar cells. Silicon nanowires are fabricated at a temperature of 375 °C by Vapor Liquid Solid (VLS) method. Nanowire solar cells have an average specular reflectance of 6.3% as compared to 22.6% for the thin film amorphous silicon (a-Si) device (over λ = 350 nm − 750 nm). Similarly the average diffuse reflectance of the nanowire devices is 4.9% as compared to 9.4% for the thin film a-Si device. External quantum efficiency measurements indicate the largest contributor to collection efficiency losses is from the catalyst impurity used for nanowire growth.