The electronic state of Y doped ZnO (YZO) was calculated using the density functional theory. In this study, the program used for the calculation on theoretical structures of ZnO and YZO was Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The detail of electronic structure was obtained by the discrete variational Xα (DV-Xα) method, which is a sort of molecular orbital full potential method. The density of state and energy levels of dopant elements was shown and discussed in association with optical properties, especially related to down-conversion effect. The down-conversion effect of YZO was experimentally investigated by preparing thin films deposited on F doped SnO2 (FTO) glass substrates by sol-gel method using the spin-coating system. A homogeneous and stable solution was prepared by dissolving acetates in the solution added diethanolamine as sol-gel stabilizer. In order to confirm a ultraviolet ray interruption and down-conversion effects, the transmission spectrum and the fluorescent spectrum of YZO films were estimated. The results obtained by experiment were compared with the calculated structure.
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