Large-scale fabrication and the optical properties of tower-like zinc oxide structures

Large-scale uniform ZnO nanotowers on silicon substrate have been prepared by the thermal evaporation method at 950°C using Au as the catalyst. The morphology and microstructure of the as-synthesised ZnO nanotowers were characterised by scanning electron microscopy and X-ray diffraction. The room temperature photoluminescence spectrum of the as-synthesised ZnO nanotowers shows a strong ultraviolet emission peak at 380 nm and a weak green emission at 540 nm, revealing that there are a few deep-level defects in the single ZnO structure. The growth mechanism of the as-synthesised ZnO structures is also discussed.