Experiments And Theoretical Research On The Surface Patterning Of Nanoparticle Oxide Thin Film

With the further study of nanomaterials and the progress of nanoparticles preparation technology, people find that the physicochemical properties of nanostructure ZnO and bulk materials are significantly different because of the quantum size effects, etc. In this paper, the surface patterning of nano-zinc oxide thin films have been prepared, and the optical properties are measured and simulated in theory.With the nanosphere lithography technique, firstly, a single layer and a large area polystyrene microspheres mask were prepared, including350nm,500nm,600nm and1μm in diameter, and then a layer of zinc oxide thin film on the mask board were deposited by RF magnetron sputtering technique, anneal two hours at the temperature of450℃to remove the polystyrene spheres finally, at the same time, the crystallization of ZnO are improved. In this way, the surface patterning of nano-zinc oxide thin films in different diameters are prepared.The samples are characterized on the morphology and composition by scanning electron microscopy and energy dispersive X-ray spectrometer. The results showed that the samples are arrangement of punctate or ring-like ZnO nanoarray. The XRD results indicate that the samples have (100),(101) and (110) ZnO characteristic diffraction peaks. To measure by absorption spectroscopy in the range from300to800nm at room temperature, the absorption edge turns up blue shift with the decrease in the diameter of polystyrene colloidal spheres, namely the nano-particles diameters; red shift while the increasing of the ZnO nanoarray thickness. By fluorescence spectral measurement, the samples all have a clear UV emission peak. With the decrease of zinc oxide nanoparticle size, the emission peaks turn out obvious blue shift.In addition, theoretical calculation based on the Mie theory and discrete dipole approximation are performed to simulate the optical extinction properties of the zinc oxide nanoparticle arrays between300nm and800nm.With the software MieCalc based on Mie theory, the extinction properties of spherical ZnO particles in different size are simulated. Discrete dipole approximation theory can be used to calculate the absorption of the particles of any shape and size. In current references, 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 rarely reported. In this paper, this theory has been used to calculate the optical absorption properties of Triangle-shaped prism 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.