Charge transport in single crystalline indium nitride Nanowires

Single crystalline InN nanowires have been synthesized via vapor-liquid-solid growth mechanism in a chemical vapor deposition system. It exhibits wurtzite hexagonal crystal structure with lattice constant a = 3.5{\AA} and c = 5.7{\AA}. Energy dispersive spectroscopy measurement indicates indium and nitrogen concentrations with stoichiometry of 1:1. The as-synthesized nanowires (average diameter of 100nm) are then configured into field effect transistor devices and measured in a variable temperature cryostat. From the electrical transport data, the nanowire channel shows typical n-type semiconductor behavior. As temperature increases from 4.2 K to room temperature, a metal-semiconductor transition is observed at a temperature around 80 K. It is found that in the semiconductor regime, the resistivity follows a power law dependence due to electron hopping mechanism. In addition, this is confirmed by the negative magneto-resistances observed for magnetic fields applied with directions both perpendicular and parallel to the nanowire axes.