水热法制备Co掺杂ZnO纳米棒的及其光学性能分析

The Hydrothermal Preparation and Analysis of Optical Properties of Co-doped ZnO Nanorods

采用水热法制备了不同Co掺杂浓度的六方纤锌矿结构的ZnO纳米粉体材料,通过X-射线衍射(XRD)、扫描电镜(SEM)和(光致发光)PL谱对样品的形貌、结构、光学性能分别进行了表征和测试.XRD分析结果表明:Co掺杂并未改变纤锌矿ZnO的晶体结构;SEM可以看出随着Co掺杂浓度的增大,花状ZnO纳米棒的均匀性变差,而且不同浓度Co掺杂ZnO纳米棒中均出现了少量的且尺寸较小的单根纳米棒;而PL光谱显示样品在381nm附近具有微弱的紫外发光峰,在位于579nm附近具有较强的可见光发光峰.特别是Co掺杂ZnO纳米棒的紫外发光峰强度同本征样品相比没有明显的变化,而可见光发光强度同本征样品相比具有明显的下降.随着Co掺杂浓度增大,样品可见发光峰的强度先减小再增大,说明样品的结晶质量先提高再降低.当Co掺杂的浓度为2.0%时,所制备的ZnO花状纳米棒具有良好的结晶质量,具有优异的光学性能.

In this paper,the ZnO nanopowders with hexagonal wurtzite structure are synthesized by hydro-thermal method with different concentrations of Co. The morphology,structure and optical properties of the samples are characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and photo-luminescence(PL). XRD results show that Co doping does not change the crystal structure of wurtzite ZnO. SEM shows that the uniformity of flower-like nanorods decreases with the increase of Co doping concentration. Moreover,a small number of single nanorods with small size are found in ZnO nanorods doped with Co at different concentrations. It can be seen from the PL spectrum that the sample has a weak ultraviolet luminescence peak at around 381 nm,and has a strong visible light luminescence peak at around 579 nm. We find the intensity of the ultraviolet luminescence peak of the Co-doped ZnO nanorod is not significantly comparable to that of the intrinsic sample. But the visible light luminous intensity has a significant decrease from the intrinsic sample ratio. With the increase of Co doping concentration,the intensity of the visible luminescence peak of the sample first decreases and then increases which indicating that the crystallization quality of the sample first increases and then decreases. When the concentration of Co doping is 2.0%,the prepared ZnO flower-like nanorods have the good crystallization quality and optical properties.