Topics on Diamond as a Functional Material

Abstract

The research and development of diamond as a functional material has been reviewed focusing attention on diamond films synthesized by chemical vapor deposition (CVD). Diamond has a potential as a versatile functional material characterized by unique properties. Initially, a brief overview on the relation between the well-known properties and applications is given. It is shown that practical applications rely on polycrystalline films, while future applications as semiconductors or solid state lasers rely on single crystal films and require further technical advancement in high quality (and high purity) crystal growth, epitaxial growth and impurity doping. It is also pointed out that the unique surface property of diamond provides new fields of applications in addition to those that utilize the known bulk properties. A few examples of interesting applications including surface acoustic wave (SAW) filters andelectrodes for electrochemical uses, and results of surface studies are described in some detail. Interesting topics related to future applications are described briefly covering various categories as an overview for future possibilities.