Effect of constituent phases of reactively sputtered AgOx film on recording and readout mechanisms of super-resolution near-field structure disk

We have studied the dependence of the constituent phases of reactively sputtered AgOx mask layer on the recording and readout mechanisms of super-resolution near-field disk. At low oxygen flow ratios, the AgOx mask layer was found to be composed of an appreciable amount of Ag particles with sizes of tens of nanometers and Ag2O phase. After recording by a high power laser pulse, a hollow Ag cylinder that had its center filled with O2 was formed in the AgOx mask layer. The hollow Ag cylinder would serve as an aperture and could effectively reduce the laser spot size during readout, leading to the super-resolution effect only. At high oxygen flow ratios, the AgOx mask layer was found to be mostly composed of Ag2O and/or AgO phases. After recording by a high power laser pulse, a hollow Ag cylinder that had its center filled with nanosized Ag particles was formed in the AgOx mask layer. The nanosized Ag precipitates would serve as light-scattering centers and could yield strong near-field interaction with the subwavelength marks, resulting in both the super-resolution and near-field effects during readout.