Fabrication And Photoluminescence Properties Of ZnO Nanowire Arrays

Well-aligned ZnO nanowire arrays were synthesized by using of chemical vapor-deposition (CVD), physical vapor-deposition (PVD) and sol-gel method. SEM and TEM were used to investigate the corresponding morphologies and microstructures. The sample phases, crystal structures and chemical compositions were detected by XRD and SAED. The RTPL and Raman spectra were studied. The influence of doping was also been studied. The results were listed as follows:1. Well-aligned single-crystalline wurzite zinc oxide (ZnO) nanowire arrays were successfully fabricated on a Si substrate by a simple physical vapor-deposition (PVD) method at a relatively low temperature of about 500?C. The as-fabricated nanowires were preferentially arranged along the [001] direction of ZnO. The photoluminescence spectrum of ZnO nanowire arrays showed two emission bands: a strong green emission at around 500 nm and a weak ultraviolet emission at 380 nm. The strong green light emission was related to the existence of the oxygen vacancies in ZnO crystals. Corresponding growth mechanism of the ZnO nanowires was briefly discussed.2. Hierarchical architectures have been synthesized by thermal evaporating amorphous Zn-Fe-C-O composite powder, in which the as-synthesized architectures consist of single crystalline Fe-doped ZnO nanocantilever arrays. The characterizations of composition, structure and phonon spectrum properties of the nanocantilevers have been performed. Arrays of uniform, perfectly aligned and single-crystal nanowires have been observed by electron microscopy (periods of several tens nanometers are seen). The results of the X-ray photo-electric spectra and the Raman spectrum provide the evidence that Fe is incorporated into the ZnO lattice at Zn site. Abnormally, the room temperature UV emission band of Fe-doped ZnO nanocantilevers disappears and the green one has a large red-shift, as well as the green emission intensity is strongly quenched because the Fe3+ enters the ZnO crystal lattice.3. Ni-doped comb-like zinc oxide (ZnO) semiconductor nanostructures have been synthesized by a simple chemical vapor-deposition method (CVD) at relatively low temperature. The as-synthesized ZnO nanocombs consist of an array of very uniform, perfectly aligned, evenly spaced and long single-crystalline nanobelts (nanowires) with periods of about several tens of nanometers. X-ray diffraction and Raman spectra results provide the evidence that Ni is incorporated into the ZnO lattice at Zn site. Photoluminescence spectra of the as-obtained samples have been detected, in which the incorporation of donor Ni leads to the increases of the ultraviolet emission intensity and a blue-shift of emission peak. This technique can be used to prepare other semiconductors and morphology-controlled doping nanocombs.