Using ZnO buffer layers prepared by simply thermal oxidation of ion beam sputtered Zn films, highly oriented and uniformly aligned single-crystalline ZnO micropillars arrays have been synthesized by thermal evaporation of Zn powder with free catalysts at low temperature of 430 ℃. The ZnO micropillars show sharp hexagonal umbrella-like tips with thin ZnO nanowire grown on the tips. The umbrella-like tips grow in a layer-by-layer mode along the direction of [001]. The growth mechanism has been discussed. The formation of the micropillars basically de-pends on the gradually decreasing Zn vapor pressure and subse-quently cooling process. The photoluminescence (PL) spectrum indicates a moderately good crystal quality of the ZnO micropil-lars. Our results may reinforce the understanding of the formation mechanism of different ZnO nano/microstructures. This kind of complex microstructures may find potential applications in multi-functional microdevices, optoelectronic and field emission devices.
LU Hongbing TIAN Yu HU Meifeng SHUAI Min LI Jinchai
