Additional possibilities for complex analysis of two-dimensional coatings (thickness <1 nm or <10 ML) grown by physical vapor deposition (PVD) on a single-crystal silicon substrate under two deposition regimes are revealed: 1) low-temperature (at low beam temperature) and 2) high-temperature (at an elevated temperature of the beam), respectively. Coatings, including in the form of pure metal and a silicide mixture, and their interface with the substrate were analyzed by Auger electron spectroscopy (AES) and characteristic electron energy loss spectroscopy (EELS). To ensure both deposition regimes, a technology of the deposition from the ribboned source was developed. The traditional use of AES is limited to determining the composition of the elements, the energy electronic structure, and the thickness of the coating. And EELS — the types of phases (the density of valence electrons) and the stages of their formation. The simultaneous use of both methods and the choice of equal (and minimal) probing depths, ~ 2.5 nm (primary electron energy 300 eV), provided new possibilities for studying subnanometric two-dimensional coatings, in particular, — for comparison of the composition of coatings and their density. The chosen probing depth made it possible to characterize also interface between coating and substrate. At the same time, the same probing depth made it possible to use the thickness of the coating obtained from the AES data to analyze the data of the EELS. In addition, other possibilities are considered. This is the use of dependencies: a) the energy of the plasmon satellite of Auger peak, depending on the thickness of the coating, for analyzing changes in the electron density in the near-interface layer of silicon; B) attenuation of the Auger signal generated by marker atoms at the interface between the coating and the substrate to localize the places of adsorption of deposited atoms; and c) the intensity and energy of the loss peaks in the EELS in dependence on the primary-electron energy for profiling the composition of coatings over the depth. The use of two attenuation functions for two depths of probing provided a quantitative Auger analysis of binary coatings. All this made it possible to characterize more fully both the two-dimensional coatings themselves and the interface layer of the substrate, as well as the processes of their formation. And, in particular, this made it possible to identify for the first time the wetting nanophase layer of metal on a silicon substrate, to investigate the process of its formation and to show how its composition depends on the modes of vapor-phase physical deposition.
MODELING OF PROCESSES AND MATERIALS
The paper deals with the construction of numerical models of heat transfer in a multilayer AlAs/GaAs nanostructure. The problem is solved using a hybrid finite-difference-mesh-free method based on radial-basis functions. The obtained solutions are compared for various bases, as well as with and without normalization of the approximating model. The possibility of increasing the speed of computations due to the parallelizability of computations is investigated, it is shown that, using multiprocessor systems, one can achieve a significant increase in performance.
NANOMATERIALS AND NANOTECHNOLOGY
Titanium alloys approved for clinical use in our country are widely used in traumatology, maxillofacial surgery and stomatology, mainly for the manufacture of various endoprostheses and dental implants, i.e. structures, introduced and installed in the bone and soft tissues of human body, able to both bio-integrate and bio-adaptable in the tissues of human body.
In the field of medical materials science and in particular in the development of medical products based on titanium and its alloys and various coatings on the surface of such products, modern methods and modern equipment developed for the electronics industry are successfully used.
In this paper, the methods of research of materials and structures of electronics used in the field of medical technology and specifically in the development of medical titanium endoprostheses have made it possible to develop the basics of the technology for obtaining optimal microrelief on the surface of titanium endoprostheses intended for engraftment in soft tissues (i.e. fibrointegrable) with bioactive coating of titanium dioxide TiO2 with an anatase structure obtained by atomic-layer deposition. The research aimed at revealing the optimal surface treatment of such endoprostheses in order to achieve improved fibrointegration properties in their use in maxillofacial surgery has been carried out.
It has been shown that high adhesion and fibrointegration between the titanium endoprosthesis and connective tissue are achieved with an average surface roughness (4—8)⋅102 nm, root-mean-square roughness 5⋅102—1⋅103 nm, profile height (3—6)⋅103 nm, and thickness bioactive coating in the order of 10 nm.
EPITAXIAL LAYERS AND MULTILAYERED COMPOSITIONS
The aim of this work was to study the influence of the iron and carbon doping of the epitaxial GaN layer on sapphire on the growth features of epitaxial films and their dislocation structure. Investigation methods used were: mass spectroscopy of secondary ions, selective chemical etching on spherical sections, and also single-crystal diffractometry.It is shown that doping during growth of an epitaxial GaN layer with carbon can lead to a significant decrease in the dislocation density in epitaxial layers.It has been shown that for samples doped with iron, a decrease in the number of short dislocations located in the bulk of the structure is characteristic, but a large number of extended dislocations are generated contributing to the diffusion of iron into the working regions of heterostructures, which can adverselyinfluence on the electrical parameters of the structures. In the course of the work, a technique for determining the density of dislocations in epitaxial films was proposed using two schemes of selective etching of spherical thin sections, which makes it possible to determine the dislocation density distribution over the depth of epitaxial films.
PHYSICAL CHARACTERISTICS AND THEIR STUDY
The differential equation of the second order including function of distribution of density of a mobile charge in the compensated layer p-i-n of transition of the diode on the basis of GaN is received. The decision of the equation is executed by a numerical method with application of program MathCad. The electric field on border of the compensated layer (CL) and the compensated layer pays off from a condition, that concentration made diffusion in CL of electrons is much more than concentration of the motionless compensated ions of an impurity. Electrons from strongly alloyed layer made diffusion in CL, leaving in it positively charged ions donor impurity. Between layers mobile of electrons and ions the electric field E which a drift stream counterbalances diffusion a stream is created. The charged layers of mobile carriers of a charge shield an external electric field.
By results of the decision of the differential equation diagrams of distribution of an electric field and potential in the field of a spatial charge p-i-n transition on the basis of GaN in view of influence of free carriers of a charge are constructed. It is shown, that on a site volt ampere to dependence when it is broken it exponential dependence, in the compensated layer the drift field limiting growth of a direct current is created.
GENERAL ISSUES
The features of nanomaterials as objects of intellectual property (OIS) are considered. The role of the information-analytical system of the MITIS “Intellectual Property: Protection and Commercialization” in the legal protection and commercialization of the results of scientific and technical activities is shown. The methods of evaluation of intellectual property objects are considered and the comparative characteristics of OIS estimation methods are given. As the OIS of the nanoindustry, the development of a new technology for the synthesis of the FeCo/C nanocomposite was chosen. The use of FeCo/C metal-carbon nanocomposite and the substantiation of the choice of the design solution for nanocomposite production technology are considered. The feasibility study of the FeCo/C nanocomposite production project was completed and the market value of the developed technology was estimated.
ISSN 2413-6387 (Online)