Carbon-assisted synthesis of aligned ZnO nanowires

Large-scale aligned ZnO nanowires are grown uniformly on silicon substrates covered with polycrystalline ZnO films by carbothermal route, without employing any metal catalysts and vacuum system. The products collected from the different temperature zones were characterized using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. It was found the (001) oriented single crystal ZnO nanowires with different diameters could be fabricated. It is suggested that the ZnO films with smaller grain sizes may offer the nucleation centers for the formation of ZnO nanowires.