Improved conductivity and long-term stability of sulfur-passivated n-GaAs nanowires

The surface passivation of n-type GaAs nanowires (NWs) by ammonium polysulfide solution, (NH4)(2)S-x, is described. The passivation resulted in a two order of magnitude increase in current density in an ensemble NW device. A depletion and recombination model is used to explain the results in terms of a reduction in surface trap density upon passivation. The results are comparable to a previous passivation method using AlInP shells. The S passivation was found to be unstable according to the degradation in the ensemble NW conductivity after a 7 months exposure to air. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4719675]