Materials aspects in phase change optical recording

Phase change recording materials used in reversible optical recording disks are briefly reviewed with focus on Ge–Sb–Te and Ag–In–Sb–Te materials. Methods that lead to a high crystallization rate of the Ge–Sb–Te recording layer are discussed. The role of recording layer composition, its thickness and interface layers, is especially emphasized. It is demonstrated that the methods used for increasing the crystallization rate of Ge–Sb–Te materials usually lead to opposite results in Ag–In–Sb–Te because of their different crystallization mechanisms: nucleation-driven vs growth-driven crystallization processes. Using Ge–Sb–Te and Ag–In–Sb–Te as example materials, a method is introduced for distinguishing crystallization mechanisms of an amorphous material.