Low-temperature synthesis of silica-enhanced gallium nitride nanowires on silicon substrate

Abstract

Low-temperature synthesis of GaN nanowires is successfully achieved by silica-enhanced processes. GaN nanowires were synthesized by reaction of metal gallium vapor with ammonia and hydrogen gases at the temperature of 700 °C on the amorphous SiO2 substrate. From scanning electron microscopy images, the morphologies of GaN nanowires are wirelike with a length up to 5μm and the average diameter of GaN nanowires measured by transmission electron microscopy (TEM) is about 25 nm. The x-ray diffraction analysis of as-synthesized products indicates that the nanowires have the hexagonal wurtzite structure of GaN crystal. The corresponding electron diffraction pattern also indicates that the as-synthesized GaN nanowires exhibited a single-crystal feature with uniform oxygen doping characterized by electron energy loss spectroscopy. The compositional line profile of TEM analysis reveals that GaN nanowires are terminated by Au nanoparticles, which infer an evidence that the vapor-liquid-solid model is the major growth mechanism.