Yongyou Geng

Write-once medium with BiOx thin films for blue laser recording

BiOx films are prepared by reactive direct current (DC) magnetron sputtering from a metallic bismuth target in Ar + O2 with different O2/Ar ratios. It is found that the optical property of BiOx films is sensitive to O2/Ar ratios and the films deposited at O2/Ar ratio of 0.5 have the best reflectivity contrast under the same conditions. The structure and optical characteristics of the films are studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectrophotometer. As revealed by investigations, the phase transition is mainly responsible for the change of optical properties. The static test results indicate that the BiOx films have good writing sensitivity for blue laser beams. A high reflectivity contrast of about 52% at a writing power of 11 mW and writing pulse width of 800 ns is obtained. In addition, the films demonstrate good stability after being read for 10000 times.

High speed recording property of phthalocyanine thin film for compact disc recordable

In this paper, spin-coated thin films of phthalocyanine dye were prepared. Absorption spectrum of the thin film shows a comparatively broad absorption at the wavelength region 630 - 770 nm and there is a steep absorption edge at the wavelength 750 nm, which is crucial to high reflectivity. Optical parameters of the thin film was measured by a spectroscopic ellipsometer. Extinction coefficient found to be very little at the wavelength 780 - 810 nm. 5-in CD-R discs made of this dye exhibit good performance after recorded in Yamaha 20 speed recorder. Jitters of land or pit are less than 35 ns and the 3T-11Ts signals show very good quality. This dye is promising recording media for CD-R for much higher speed recording in the future.

Optical recording performance of an azo metal chelate thin film for DVD-R

A new azo metal chelate thin film has been developed for digital versatile disk recordable (DVD-R) by means of a spin-coating. The absorption of the film matches very well with the wavelength of the GaAlInP semiconductor diode laser (0.63 approximately 0.65 μm). Thermal property of azo metal chelate indicates that the rapid decomposition of the dye happens in the narrow temperature zone. The optical recording performance of the azo nickel chelate thin film shows that high reflectivity contrast (34%) can be obtained at low writing power and short writing pulse-width using He-Ne laser (632.8 nm) irradiation. The average jitter of 5-in DVD-R disk after recorded with optimistic power on DVD-RT650 tester is less than 12%.

Thermal and optical recording property of an azo-nickel chelate thin film as short-wavelength optical recording media

A new azo nickel chelate thin film has been developed for short wavelength write-once optical recording by a spin-coating process. Thermal property of the dye was studied by thermo-gravimetric analyzer (TGA). The azo nickel chelate begins to decompose at temperature 295.6°C, which is 44°C above that of azo, and rapidly decomposes in the narrow temperature range. A dynamic optical recording test on the disc made of this dye indicated that the CNR of written signals was more than 43dB at low writing power and short writing pulse-width using Ar+ laser (514 nm) irradiation in a wide scan velocity range.