title: Radial junction amorphous silicon solar cells on PECVD-grown silicon nanowires.
abstract: Constructing radial junction hydrogenated amorphous silicon (a-Si:H) solar cells on top of silicon nanowires (SiNWs) represents a promising approach towards high performance and cost-effective thin film photovoltaics. We here develop an all-in situ strategy to grow SiNWs, via a vapour-liquid-solid (VLS) mechanism on top of ZnO-coated glass substrate, in a plasma-enhanced chemical vapour deposition (PECVD) reactor. Controlling the distribution of indium catalyst drops allows us to tailor the as-grown SiNW arrays into suitable size and density, which in turn results in both a sufficient light trapping effect and a suitable arrangement allowing for conformal coverage of SiNWs by subsequent a-Si:H layers. We then demonstrate the fabrication of radial junction solar cells and carry on a parametric study designed to shed light on the absorption and quantum efficiency response, as functions of the intrinsic a-Si:H layer thickness and the density of SiNWs. These results lay a solid foundation for future structural optimization and performance ramp-up of the radial junction thin film a-Si:H photovoltaics.
authors.affiliation: Laboratoire de Physique des Interfaces et des Couches Minces (LPICM), Ecole Polytechnique, CNRS, F-91128 Palaiseau, France. Linwei.yu@polytechnique.edu
authors.forename: Linwei
authors.initials: L
authors.lastname: Yu
authors.forename: Benedict
authors.initials: B
authors.lastname: O'Donnell
authors.forename: Martin
authors.initials: M
authors.lastname: Foldyna
authors.forename: Pere
authors.initials: P
authors.lastname: Roca i Cabarrocas