Synthesis and Strong Blue-Green Emission Properties of ZnO Nanowires

ZnO nanowires were catalytically grown on Au-coated silicon substrates by the carbon thermal reduction method. The process involved addition of a low partial pressure of hydrogen sulfide to the argon carrier flow. The addition of H₂S led to the higher yield and longer nanowires without any morphology change, and no sulfuric content was observed by the energy dispersive x-ray spectroscopy in the resulting nanowires. The nanowires exhibited strong blue-green emission at room temperature and an increasing intensity when the partial pressure of H₂S was raised. The temperature-dependent photoluminescence spectra show that intensity of the blue-green emission, almost without shift, decreases slowly with increasing temperature. Heat treatments indicated that quenching resulted in a higher ratio of blue-green emission to ultraviolet emission.