Ag掺杂ZnO微纳米结构的制备及发光特性

Preparation and Optical Properties of Ag-Doped ZnO Micro-Nano Structure

采用微波水热法在80~140℃的生长温度下合成了一系列银(Ag)掺杂的氧化锌(ZnO)样品,掺杂液中Ag^(+)质量分数分别为0、0.2%、0.5%和1%,并采用X射线衍射(XRD)、扫描电镜(SEM)、室温荧光(PL)等方法详细研究了Ag的掺杂对ZnO的结构、形貌和光学性能的影响。XRD结果显示,在低温条件下,高浓度Ag掺杂的ZnO结晶质量最好,而在高温条件下,纯ZnO的结晶质量优于Ag掺杂样品;SEM结果表明,ZnO为空心纳米结构,纯ZnO样品随着温度的升高,样品的形貌由中空的棒状结构逐渐转化为多层的片状结构,而随着Ag掺杂浓度的增加,中空的六方柱状结构逐渐解体,样品颗粒减小,这一现象符合介孔形成的基本理论——柯肯达尔效应;PL光谱表明,随着Ag掺杂浓度的增大,ZnO的可见光发光强度呈现出先增强后减弱的趋势,能带的带隙则逐渐变窄。Ag的掺杂浓度和样品生长温度对于ZnO的结构、形貌和光学性能起了关键性作用。

Zinc oxide(ZnO)samples with silver(Ag)doping concentrations of 0,0.2%,0.5%,and 1%are synthesized by microwave-assisted hydrothermal method at the growth temperatures of 80-140°C.The effects of Agdoping on the structural,morphological,and optical properties of ZnO are investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM),and room-temperature photoluminescence(PL).The XRD results show that the crystal quality of ZnO with high Ag-doping concentration is the best at low growth temperature,while that of pure ZnO is better than that of doping samples at high temperatures.The SEM results show that formed ZnO holds the hollow nanostructure,and the morphology of pure ZnO samples gradually transforms from a hollow rod-like structure to a multilayer lamellar structure with the increase of growth temperature,while the hollow rod-like structure gradually disintegrates and the sample particles decrease with the increase of Ag concentration,which is in line with the basic theory of mesoporous formation-the Kirkendall effect.The PL results show a trend of increasing and then decreasing for the visible emissions of ZnO with the increasing doping concentration of Ag,while the energy band becomes narrower.The doping concentration of Ag and growth temperature of the ZnO samples play a key role in the structural,morphological,and optical properties of ZnO.