HX-PES Study of Rewritable Phase-Change Recording Media

Abstract

The influence of the interface layer to the chemical and electronic states of a phase-change recording material, GeBiTe (GBT) alloy, used in the high-speed rewritable HD DVD media was investigated for the first time using the hard x-ray photoelectron spectroscopy (HX-PES). The density of states (DOS) for the valence band of the amorphous state without an interface layer was smaller than that of the crystalline state. The band-edge energy of the amorphous state without an interface layer was lower by about 0.5 eV than that of the crystalline state. On the other hand, the DOS and the band-edge energy of the amorphous state of GBT with interface layers were almost same as that of the crystalline state, respectively. This result may lead to almost the same career density for electrical conduction for the crystal as the amorphous, which is totally unexpected thus very interesting because the atomic arrangements should differ from each other. We speculate that this effect is a factor for a high-speed crystallization.