Chapter 2: Structure and Properties of Amorphous Thin Films for Optical Data Storage

Overview

With the astonishing progresses of the computer and network applications, as well as audio-video (A/V) appliances the information volume has been greatly increased. 21st century is the tera-bit (10 ¹² bits) information century. The processing, transfer and storage of the tera-bit information must be based on the characteristics of super-high density and super-high transfer rate. In recent years, optical data storage has been a very rapid developing field in response to the ever-growing demands. The optical nano-recording is arising now for huge information storage.

The amorphous thin films have played an important role in optoelectronic and photonic devices, especially in optical data storage owing to easy fabrication and integration. There is no grain boundary in amorphous thin films, it is easy to get high quality thin films with very fine surface roughness, suitable for nano-storage with low-level noise.

The magneto-optical (M-O) recording and phase change (P-C) recording are still the main approaches for high-density optical data storage, especially for rewritable storage. Both the recording media are amorphous; they are amorphous rare earth-transition metal (RE-TM) alloys and amorphous chalcogenide alloys. Some amorphous metallic and semi-metallic alloy thin films are also used for storage media and optical nonlinear mask (ONM) media. The structures of amorphous thin film materials exhibit quite complex and complicated features. To understand the structural relation with their properties and to interpret their storage mechanism are very important. The fundamentals of optics, as well as magneto-optical and optical recording properties of glass thin films have been introduced...