GaAs nanowire Schottky barrier photovoltaics utilizing Au-Ga alloy catalytic tips

Single GaAs nanowire photovoltaic devices were fabricated utilizing rectifying junctions in the Au-Ga catalytic tip/nanowire contact interface. Current-voltage measurements were performed under simulated Air Mass 1.5 global illumination with the best performance delivering an overall energy conversion efficiency of similar to 2.8% for a nanowire of 70 nm in diameter. As compared with metal contacts directly deposited on top of the nanowire, this nanoscale contact is found to alleviate the well-known Fermi-level pinning to achieve effective formation of Schottky barrier responsible for the superior photovoltaic response. All these illustrate the potency of these versatile nanoscale contact configurations for future technological device applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4727907]