Short-wavelength optical storage properties of GeSb2Te4 phase-change thin films

The optical properties of GeSb2Te4 thin films prepared by vacuum RF-sputtering method at the wavelength region of 400 - 830 nm were studied. A comparatively large absorption was observed in the wavelength range 400 - 600 nm, which matches with the wavelengths of Argon laser. The optical storage characterizations of GeSb2Te4 thin film demonstrate clearly that larger reflectivity contrast can be obtained at lower power Argon laser (514.5 nm) irradiation. The erasing contrast is relatively lower but can be improved by multi-layer films match.