Fundamentals and Applications of Diamond

Abstract

Dear colleagues, We are pleased to introduce you to this Special Issue of physica status solidi (a), focussed on fundamental and applied science and technology of diamond and nanodiamond materials. This special issue aims at providing a brief but hopefully broad overview of those topics that are today at the centre of the diamond community's current interests, such as diamond growth and doping, colour centres, nanophotonics, devices and electronics, bioapplications of diamond and nanodiamonds, surface properties, etc. The Feature Article by Dean Ho and Han Man 1 reviews the use of diamond materials in various nanomedicine applications, with a particular focus on therapeutics and drug delivery. They demonstrate that, in addition to their well-known properties such as biocompatibility and outstanding imaging capability, diamond nanoparticles are promising vehicles for drug delivery resulting in enhanced therapeutic efficacy and reduced premature drug release. This exciting field of applications is expected to grow rapidly with the full understating and control over the surface functionality of diamond nanomaterials. A relatively recent field of excitement for the diamond community is nanophotonics, an area of research that has rapidly evolved from the study of colour centres in bulk diamond to a plethora of phenomena and applications enabled by a precise nanostructuring of diamond single crystals. In their Feature Article, Birgit Hausmann and colleagues 2 from Harvard University review some of their recent contributions, such as the use of diamond nanowires to increase single photo collection from nitrogen-vacancy (NV) centres embedded in these nanostructures, or the coupling of single NV centres to planar resonators on-chip. This article highlights the outstanding challenges that still need to be addressed both in terms of fabrication nanotechnology, implantation of colour centres, and device design. The third Feature Article in this special issue, by Markus Dankerl and colleagues 3 of the Walter Schottky Institute, reviews solution-gated field effect transistors (SGFETs) based on surface-conductive single crystalline diamond with a focus on bioelectronic applications, in particular for the development of cell-transistor electronic interfaces. The article covers technology aspects, fundamental issues of the diamond/electrolyte interface, and finally reports on the successful recording of cell's action potentials using arrays of diamond SGFETs. In a special issue related to diamond, the most demanding challenge for the community, i.e. the growth of high quality diamond films and their doping, cannot be missing. In the Editor's Choice article, André Sartori and co-workers 4 provide a detailed study of in-situ boron doping during heteroepitaxial growth of diamond, a promising path towards the preparation of doped, high-quality, large area diamond thin films, which is a step that seems mandatory for the success of any of the potential applications of diamond in electronics. In another contribution, Jocelyn Achard et al. 5 explore the suitability of boron-doped freestanding diamond single crystals for vertical power electronic devices. In contrast to the most standard co-planar structures, the vertical configuration offers several advantages, at the expense of requiring high quality, heavily doped, thick films. The electrical characterization of diamond films as well as of diamond devices is still a very active topic in the diamond community, and is well represented in this special issue of physica status solidi (a). For instance, the contribution by Yuto Hoshino and colleagues 6 reports on the electrical properties of a novel lateral p–n junction diode fabricated by selective growth of phosphorous n+ diamond, aiming at avoiding some of the drawbacks of vertical p–n junctions. Two studies report on fundamental aspects of the electronic properties of charge carriers in diamond films. J. Barjon et al. 7 characterize homoepitaxial boron-doped diamond, grown with a very residual donor impurity concentration which results in low compensation and thus films exhibiting high conductivities. In their contribution, P. Ščajev et al. 8, provide an extensive study on the effect of the crystalline structure of diamond films on the carrier recombination and diffusivity. With this special issue of physica status solidi (a) we do not only aim at providing you with a selection of the currently most active fields of research related to the science, technology, and applications of diamond. In addition, we also hope that the contributions included in this issue can help to point out the challenges ahead while at the same time provide inspiration for your future work. Garching & Hasselt, September 10, 2012 Jose A. Garrido Miloš Nesládek Ken Haenen