Sulfur passivation for ohmic contact formation to InAs nanowires

We have studied the formation of ohmic contacts to InAs nanowires by chemical etching and passivation of the contact areas in an ammonium polysulfide, (NH4)(2)S-x, water solution. The nanowires were exposed to different dilution levels of the (NH4)(2)Sx solution before contact metal evaporation. A process based on a highly diluted ( NH4)S-2(x) solution was found to be self-terminating, with minimal etching of the InAs. The stability of the contacts was investigated with electrical measurements as a function of storage time in vacuum and air.