Machulianskyi O. Nanostructured metal-dielectric systems with predicted electromagnetic characteristics

The thesis for doctoral degree is devoted to the issues of development and production of nanostructured composite metal-dielectric systems and creation of functional devices based on them. The research developed methodological, algorithmic support for evaluation and analysis of electromagnetic characteristics of nanostructural systems. The experimental-analytical approach to determination of experimental values of electromagnetic parameters of nanoscale particles in metal-dielectric nanostructural systems with different structure and morphology has been further developed. The theoretical models of electromagnetic response of two-dimensional and three-dimensional metal-dielectric nanostructured systems with statistically inhomogeneous structure have been developed and improved by taking into account the statistical analysis of the nanoscale particle distribution function in the system by size. The models establish connection of electromagnetic characteristics of nanoscale components of the system and their microstructural morphological parameters with system response for electromagnetic perturbation. Experimental and analytical methods for determining the values of electromagnetic characteristics of nanosized particles in the systems with statistically inhomogeneous structure by the spectroscopic and structural studies of three-dimensional single-layer and multi-layer systems have been developed. The experimental values of electromagnetic parameters (complex specific electric polarizability, complex dielectric permittivity, refraction and absorption index) of copper, nickel and chromium nanosized particles with the size from 1 nm to 10 nm are determined in systems with a statistically inhomogeneous structure in the near ultraviolet, visible, near infrared ranges of the spectrum. The analytical asymptotic spectral and dimensional dependences of complex specific electric polarizability and complex dielectric permittivity of nanosized particles of the studied materials in the spectral range from 0.2 to 1.1 μm are established, which confirms the experimentally established features of their optical properties. The increasing values of real and imaginary parts of complex specific polarizability, absorption parameters were experimentally established for copper, nickel and chromium nanosized particles with size less than 10 nm in systems with a statistically inhomogeneous structure. At the same time the reducing values of complex dielectric permittivity, electrical conductivity of such particles to two orders of magnitude with reduction of particle size and in comparison with values of corresponding metals in macroscopic volumes were established. It has been revealed that in the investigated nanoscale particles, in contrast to metals in macroscopic volumes, absorption in the near infrared range of the spectrum are caused by intra-zone transitions of electrons conduction and is significantly weakened. It has been established that the experimental dimensional dependences of the electromagnetic parameters of nanosized copper, nickel and chromium particles with the size of less than 10 nm cannot be conditioned solely by the use of theories of classical or quantum size effects in dipole approximation. It is confirmed on the basis of the analysis of theoretical and experimentally established electromagnetic characteristics that the surface plasma dipole resonance is not fulfilled for nanosized copper particles with a size less than 10 nm. The approximation model of optical conductivity and specific absorption in the range of their interband absorption is proposed taking into account the influence of particle size on the electronic and phonon states in it. The influence on the optical properties of nanoscale metal layers in layered metal-dielectric systems, the morphological microstructures of the surrounding layers and the intermediate nanocomposite layers that appear in the formation of MD systems is experimentally shown. New metal-dielectric composite systems based on aluminum oxynitride with nanoscale metal inclusions have been developed. Selective structures with energy-saving, shielding properties and improved performance have been formed. This has provided a comprehensive solution to an important scientific and applied problem of the development of functional devices with predictable dynamic electromagnetic characteristics based on nanostructured metaldielectric systems with taking into account reliable information about the specifics of the electromagnetic properties of nanoscale components. Key words: nanosized particles, metal-dielectric systems, inhomogeneous experimental-analytical method, electric polarizability, dielectric permittivity, shielding coatin, energy efficiency.