[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 consist ent 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.