Low Temperature Thermal Evaporation Process for the Synthesis of ZnO Nanowires

ZnO nanowires were synthesized by thermal evaporation of ZnBr2 powder at relatively low temperatures of 600-700 degrees C under air atmosphere. Any catalysts and substrates were not used in the synthesis of ZnO nanowires. The ZnO nanowires had a typical diameter of 100nm and lengths up to several tens micrometers. The X-ray diffraction (XRD) pattern indicated that the ZnO had hexagonal wurtzite structure. The scanning electron microscope (SEM) image showed clearly that catalyst particles existed at the tips of nanowires. The energy dispersive X-ray (EDX) analysis revealed that the catalyst particles were composed of Zn and O. Based on the SEM and EDX results, it was suggested that the nanowires were grown via self-catalytic growth mechanism. A strong green emission was observed in the room temperature cathodoluminescence spectrum.