Optical Recording Films with Laminated Multilayer Structure ZnO/In2O3 Prepared by Pulsed Laser Deposition Method

Abstract

We fabricated optical recording films with a laminated structure composed of ZnO and In2O3, prepared on glass substrates by a pulsed laser deposition method using the split target. The film compositions were varied by changing the ratio (trace ratio) of the time required to irradiate each half section (ZnO or In2O3) of the target by an ArF excimer laser. There were large transmittance changes ΔT in the wavelength range of 350 ∼ 3000 nm, between the state immediately after deposited at room temperature and the state annealed at 400°C for the films fabricated with various trace ratio. It was found by TEM observation and XPS measurement that a mechanism which enabled to optically record for the films with a laminated structure was ascribed to the effect changing over from the oxygen-deficient state immediately after deposited to the thermal oxidized state by annealing. The maximal value of CNR = 67 dB was obtained at a peak power of 3 mW for the sample without a protection layer fabricated at the trace ratio of ZnO : In2O3 = 1 : 1. When the protection layers of ZnS: SiO2 became 30 nm, the value of CNR more than 45 dB were stably obtained in the peak power 4 ∼ 6 mW.