High conductivity in Si-doped GaN wires

Temperature-dependent resistivity measurements have been performed on single Si-doped GaN microwires grown by catalyst-free metal-organic vapour phase epitaxy. Metal-like conduction is observed from four-probe measurements without any temperature dependence between 10K and 300 K. Radius-dependent resistivity measurements yield resistivity values as low as 0.37 m Omega cm. This is in agreement with the full width at half maximum (170 meV) of the near band edge luminescence obtained from low temperature cathodoluminescence study. Higher dopant incorporation during wire growth as compared to conventional epitaxial planar case is suggested to be responsible for the unique conductivity. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4799167]