二维氧化锌纳米阵列的制备及光学吸收特性研究

采用漂移法，在玻璃衬底上制备出粒径分别为117，350和500 nm单层、大面积的聚苯乙烯胶体球掩膜板，在已制得的掩膜板上用射频磁控溅射的方法沉积一层氧化锌薄膜，最后用有机溶液四氢呋喃(THF)浸泡去除聚苯乙烯胶体球，获得不同粒径的二维氧化锌纳米团簇。通过扫描电子显微镜和能量色散X射线光谱仪对样品的形貌及成份进行表征，表明所制得样品为有序分布的蜂窝网状氧化锌纳米阵列。在室温下，通过吸收光谱仪测试样品在300～800 nm波长范围内的吸收光谱，结果表明对于具有不同尺寸晶粒的氧化锌纳米团簇样品，随着所采用的聚苯乙烯胶体球粒径的增大，即氧化锌纳米团簇粒径的增加，光吸收峰出现了宽化和红移;随着溅射时间的延长，即氧化锌薄膜膜厚的增加，光吸收率提高。此外，对氧化锌纳米团簇阵列的光吸收特性进行了基于离散偶极子近似的理论计算从而获得任意形状和尺寸粒子的吸收。目前，文献报道中用此理论计算各种形状的纳米金、银等金属的结果与实验结果相符，但是应用离散偶极子的近似理论计算氧化锌纳米颗粒的报道很少。应用此理论计算三角棱台形状的氧化锌光学吸收特性，根据氧化锌薄膜介电常数和膜厚的变化进行光吸收特性的模拟，并解释了实验结果。

Research on the Preparation and Optical Absorption Properties of Two-Dimensional ZnO Array

The present paper’s main work is firstly preparing a single layer and a large area polystyrene microspheres mask, with 117, 350 and 500 nm in diameter, and then depositing a layer of zinc oxide thin film on the mask board by RF magnetron sputtering technique, using nanospheres lithography technique to remove the polystyrene spheres by soaking with tetrahydrofuran, and two-dimensional zinc oxide nano-array samples were obtained at last. The samples were characterized on the morphology and composition by scanning electron microscopy and energy dispersive X-ray spectrometer. The results showed that the samples are zinc oxide nanocluster formed by ordered cellular reticular structures. By measuring with absorption spectroscopy in the range from 300 to 800 nm at room temperature, the absorption peak turns up with broadening and red shift with the increase in the diameter of polystyrene colloidal spheres, namely the nano-particles diameters. As the sputtering time increases, that is, the increase in the zinc oxide film thickness, the light absorption rate increases. In addition, theoretical calculation based on the theory of discrete dipole approximation was performed to simulate the optical absorption properties of the zinc oxide nanocluster arrays between 300 and 800 nm. Dipole approximation theory can be used to calculate the absorption of the particles of any shape and size. Currently, the theoretical calculation results of various shapes of nanostructured metals such as gold and silver are consistent with the experimental results. But the application of the theory of discrete dipole approximation calculation of ZnO nanoparticles was rarely reported. In this paper, this theory has been used to calculate the optical absorption properties of triangle-shaped ZnO nanoparticles array. Light absorption characteristics were simulated according to changes in the dielectric constant and thickness of zinc oxide films, and the results can be used to explain the experimental results.