Synthesis of three kinds of GaN nanowires through Ga2O3 films' reaction with ammonia

A new method was employed to obtain GaN nanowires (NWs). In this method, SiC films were deposited with radio frequency (r.f.) magnetron sputtering onto silicon substrates and annealed at high temperature, and then Ga2O3 films were deposited on top of the SiC intermediate layers and annealed in NH3 atmosphere. SiC layer was used to reduce thermal and lattice mismatch between GaN and Si, and improve NWs' quality. After Ga2O3 films reacted with NH3, a great quantity of GaN NWs with the shape of birch trunks and stalactites were found by transmission electron microscopy (TEM). At the same time, a few very even and uniform pillarlike NWs were observed. The electron diffraction patterns (EDP) show that birch trunk-shaped and pillarlike NWs are all single-crystalline structures. These NWs were also analyzed with the assistance of X-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR) and high-resolution transmission electron microscopy (HRTEM) to show their properties.