| Summary: | 碩士 === 國立中興大學 === 材料工程學研究所 === 91 === The AgOx layer has been adapted as a mask layer in the super-resolution near-field structure (super-RENS) disk. During the readout by an adequate laser power, nano-sized Ag particles are generated through the chemical decomposition of silver oxide and a localized surface plasmon coupling effect occurs between the silver particles and the sub-wavelength recording marks, yielding a strong near-field intensity and improving the readout signal intensity. Therefore, the resolution limit of Super-RENS disk can be greatly enhanced to less than 100nm.
In this study, we investigated the composition, microstructure, and phase transition of AgOx films, prepared at various flow ratios of O2/(O2+Ar), with and without protective layer. We also proposed recording and readout mechanisms for the Super-RENS disk. It was found that the phases of the as-deposited AgOx composed of Ag and Ag2O when the flow ratio of O2/(O2+Ar) was low, and changed to a mixture of Ag2O and AgO where the ratio of AgO/Ag2O increased as the flow ratio increased. After annealing at 200℃, AgOx was reduced to Ag and O2 while the decomposed Ag diffused outward and precipitated silver particles on the surface of the protective layer. The thermal decomposition of AgOx films with and without two ZnS-SiO2 protective layers was confirmed to be an irreversible process.
We also confirmed that a hollow Ag cylinder, or ring, serving as an aperture, was formed and small Ag particles were precipitated in the center region during the recording process. The small aperture can significantly reduce the laser spot size during the readout process and the strong near-field interaction between precipitated Ag particles and sub-wavelength marks can effectively enhance the readout signal. That clarifies both the super-resolution effect and near-field interaction in the Super-RENS disk.
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