Electronic conduction in GaN nanowires

Conductivity mechanisms in unintentionally doped GaN nanowires (NWs) are studied. Gated current-voltage measurements and threshold voltage modeling demonstrate the unique impact of device parameters on NW field-effect transistors as compared to conventional systems. Temperature-dependent resistivity results, acquired with a scanning tunneling microscope equipped with multiple tips, reveal only mild temperature dependence at higher temperatures, with temperature-independent resistivity observed below ∼100K indicating impurity band conduction. The likely origins and implications of these results are discussed.