Diamond is an extreme material among possible atomic aggregations in nature, and as such has many extreme properties. This unique position makes it a fascinating subject both for science and for applications. This has been particularly true in recent years, since the surprising discovery at Union Carbide (1953) of the possibility of chemical vapour deposition of diamond films at low pressures, where diamond is metastable with respect to graphite. This discovery cleared the way to the development of economical deposition techniques, that have been obtaining progressively better-quality diamond, both pure and doped, in a controlled way and for a variety of applications. The remarkable properties and applications range from mechanical (the extreme hardness, tensile and compressive strength, wear performance) to thermal (the highest conductivity), optical (wide range of trasparency), chemical (inertness to most chemicals), biological (biocompatibility) and electronic (high electronic carrier mobility, large band gap and dielectric breakdown strength, negative electron affinity), with the simultaneous presence of so many extraordinary qualities often resulting in added value for a given application.

We are presently at a turning point in the development of diamond physics and applications. While some achievements can be considered well established, on the other hand, new opportunities and challenges are facing the scientific community, particularly with regard to novel exciting deposition processes and techniques or new properties and applications in electronics. For this reason, the Italian Physical Society has considered timely to sponsor, within the “Enrico Fermi School” at Varenna, a course on “The Physics of Diamond” particularly focused on the new developments and prospects, that may well constitute a reference point for a new generation of scientists at what may possibly be the beginning of a new age in diamond. The course has attracted several of the most distinguished experts in the field as lecturers and an audience of almost as distinguished students and observers from 19 countries. Participation and discussion were lively to the very last day, ranging from traditional diamond physics to new diamond physics, and from well-known applications to the new exciting opportunities.

The material in this volume is organized in the following way: the first part (13 lectures) is essentially devoted to growth and structure, the second part to properties and applications, with a closing lecture exploring new exotic diamonds in the distant future. The earlier lectures cover extensively the many processes of plasma chemical vapour deposition, including advanced contributions in theoretical modelling of these processes. Hence novel deposition mechanisms are considered: low-temperature CVD and laser-activated processes, including the so-called QQC experiments. This first part closes with a discussion of amorphous phases. In the second part, particular emphasis is placed on electronic properties and applications. This includes an extensive discussion of doping and, in addition, the promising perspectives of diamond as an electron emitter. Its newly discovered remarkable electron affinity properties lead to a new dimension in research and development, of great strategical importance for an increasing role of diamond in electronics.

We are extremely grateful to the Secretary of the Italian Physical Society Mrs. E. MAZZI and her collaborators, for the masterly practical organization of the school, combined with their warm personalized commitment to make the two weeks spent at Villa Monastero a memorable pleasant experience for all participants. We also thank Mrs. A OLEANDRI, C. VASINI and Mr. P. PAPALI of the Editorial Office for the expert and careful editorial work on this volume.

The Directors of the School

A. Paoletti and A. Tucciarone