Staff at the Physics Department of Moscow State University have described the structural features of micron diamond crystals needle-like or filamentous shape and their interaction with fluorescent characteristics and efficiency of field emission. The luminescent properties of such needle diamond crystals can be used in various types of sensors, quantum-optical devices can be used to create the element base of quantum computers and other fields of science technology.
Girl’s Best Friend and technologists
Diamonds, which are processed jewelry diamond crystals, repeatedly praised as “a girl’s best friend.” Relatively less known fact for the layman was the widespread use of diamonds in a variety of industrial processes. The scope of technological applications of diamond jewelry is much higher than their use and have a tendency to a permanent increase, both in quantitative terms and in terms of increasing the diversity of their fields of application. Such a high practical value is a constant incentive for the researchers involved in the development of new methods of synthesis, processing, make the necessary qualities of a diamond.
One of the problems the solution of which is required for the development of a number of technologies, is to produce diamond crystals of needle-like or filamentous shape. Making this form of the original natural or synthetic diamonds may by their individual manual processing (grinding) the same way as is done in the manufacture of diamonds. Other methods include the use of lithography and ion-beam technology, by which fragments the desired shape are separated from large crystals. However, such “cutting out” methods rather costly and are not always acceptable.
The group of researchers working at the Physics Department of Moscow State University, led by Professor Alexander Obraztsov, technology has been proposed, with the help of which it is possible the mass production of small-size crystals (or crystallites) diamond needle-like shape, and threadlike. The first results obtained in the course of research conducted in this direction were published seven years ago in Diamond dial & updates Related Materials .
“The essence of the proposed method is to use a well-known pattern, which determines the formation of the polycrystalline films of elongated crystallites (” columnar “) form. Of these crystallites, for example, often it is ice on the surface of lakes that can be seen when it melts. In the manufacture of diamond polycrystalline films generally tend to provide the conditions under which their constituent crystallites columnar form closely adjacent to each other, forming a dense homogeneous structure “- says the study’s lead author, Professor of Physics of Polymers and Crystals Physics Faculty of Moscow State University , doctor of physical and Mathematical Sciences Alexander Designs.
Anything that is not a diamond is converted into a gas
Researchers from the Moscow State University have shown that previously considered “bad” diamond films consisting of the individual is not in contact with each other crystallites, can be used for the manufacture of diamond in the form of needle-like or filamentous structures geometrically regular pyramidal shape. For this purpose the film must be heated to such a certain temperature in the air (or other oxygen-containing medium). Upon heating of the film material is oxidized into a gas. Since the oxidation temperature depends on the characteristics of the carbon material, and the diamond crystallite is maximum, then it is possible to choose the temperature so that the whole gas is converted into the material, except the diamond crystallites. This relatively simple technology, combining the formation of polycrystalline diamond films with desired structural characteristics with their heating in air, allows to obtain in large quantities with some diamond crystallites varying their shapes (needle, whisker and the like). The idea of such crystallites can be obtained from electron microscopic images.
Such crystallites can be used, for example, as elements of high hardness: for high precision cutting tool processing or indenter probes for scanning probe microscopes. Such use has been described in an article published by scientists before the journal Review of Scientific Instruments . Currently, probes produced by this technology are realized as the foreign companies and the domestic market.
Manage useful properties of diamond – possible!
In subsequent works, which were carried out at the Physics Department of Moscow State University, the original technology has been significantly improved, enabling to vary the shape and dimensions of the crystallites needle and expand the potential area of application. Researchers from the State University also drew attention to the optical characteristics of a diamond of significant fundamental scientific and practical interest. The results of these studies were presented in a series of articles in the Journal of Luminescence, Nanotechnology, Scientific Reports.
In these recent publications describe the structural features of the crystallites and their relationship with the fluorescent performance and efficiency of field emission. And recently, as scientists say, probably, it is the first example of the implementation of a true diamond field emission (or cold) of the cathode, to the preparation and the study of which has been drawn considerable attention over the past two decades. The luminescent properties of the diamond needles can be used in various types of sensors, quantum-optical devices to create the element base of quantum computers and other fields of science technology.
“I especially want to note the significant contribution to these works by young scientists, Victor mites and Rinat Ismagilov, enthusiasm and hard work which made it possible to receive described in discussion papers scientific results characterized by high degree of innovation, a fundamental scientific and applied significance”, – says Alexander Samples.