Synthesis of p-Type Gallium Nitride Nanowires for Electronic and Photonic Nanodevices

Magnesium-doped gallium nitride nanowires have been synthesized via metal-catalyzed chemical vapor deposition. Nanowires prepared on c-plane sapphire substrates were found to grow normal to the substrate, and transmission electron microscopy studies demonstrated that the nanowires had single-crystal structures with a 〈0001〉 growth axis that is consistent with substrate epitaxy. Individual magnesium-doped gallium nitride nanowires configured as field-effect transistors exhibited systematic variations in two-terminal resistance as a function of magnesium dopant incorporation, and gate-dependent conductance measurements demonstrated that optimally doped nanowires were p-type with hole mobilities of ca. 12 cm2/V‚s. In addition, transport studies of crossed gallium nitride nanowire structures assembled from p- and n-type materials show that these junctions correspond to well-defined p-n diodes. In forward bias, the p-n crossed nanowire junctions also function as nanoscale UV-blue light emitting diodes. The new synthesis of p-type gallium nitride nanowire building blocks opens up significant potential for the assembly of nanoscale electronics and photonics. Semiconductor nanowires (NWs) have demonstrated significant potential as fundamental building blocks for nanoelectronic and nanophotonic devices and also offer substantial