Simulation of anti-reflecting dielectric films by the interference matrix method

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The paper presents the results of the study of the parameters of the highly sensitive active medium of the NO2 sensor based on a cholesterol-nematic mixture with an admixture of carbon nanotubes. The dependence of the change in the wavelength of the two transmission minima on the NO2 concentration for cholesterol-nematic mixture with single-walled, double-walled and multi-walled nanotubes at different concentrations of nanotubes and two concentrations of nematically liquid crystal 5CB were obtained. It is established that by changing the ratio between the concentrations of nanotubes and nematic liquid crystals, it is possible to obtain mixtures that have the maximum spectral sensitivity coefficient in a given range of gas concentration.

Section: The Results and Discussionmentioning

confidence: 99%

Higly sensitive active medium of sensor NO2 , based on cholesteric nematic mixture with impurities of carbon nanotubes

Mykytyuk

Vistak

Kogut

et al. 2021

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“…The formation of structures with needle-like crystals having a characteristic cross-sectional size of the order of nm2 are widely used in modern science-intensive technologies. Crystals with needle-shaped or pyramidal formations on the surface of the same material as the substrate material have a low reflection coefficient in a wide range of solar radiation, which makes them attractive in terms of use in the production of solar cells [12], photonic crystals [13] and biosensors [14,15]. Such films can be used in a wide range of temperatures for the production of sensor elements based on nanosized polysilicon films [16], local 3-dimensional integrated siliconinsulator structures [17], as such films can be resistant to destruction if applied protective coating.…”

Section: One-dimensional Growth Model Based On Deterministic Point Pr...mentioning

confidence: 99%

The Modeling of growth process on the surface of crystal

Politanskyi

Gorbulik

Kogut

et al. 2022

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The article is devoted to modelling the growth of thin films on the surfaces of crystals having a similar crystal structure with a small parameter of mismatch of the lattice of substances from which the film and the crystal substrate are formed. A review of modelling methods based on both analytical expressions and computational methods is made. A number of methods for modelling the most typical processes: surface formation in the form of pyramidal formations (so-called needle crystals), two-dimensional with initial islands of growth and three-dimensional uneven growth processes. To model the process of growth of needle crystals, it is proposed to use a method based on Gaussian statistics of surface height increments. The model of three-dimensional growth of the crystal surface, which uses the iterative algorithm of Foss, and which makes it possible to investigate the processes of stepped, uneven growth of crystals, is also considered. In contrast to stepwise growth, a model of submonolayer growth of a film based on the Monte Carlo method is considered. For submonolayer growth of the film, pseudo-random sequences are used, which simulate the initial arrangement of the nuclei of the nucleus of the next layer on the crystal surface. The computational characteristics of this method are determined, namely the dependence of the number of iterations on the initial surface filling coefficient.

“…Thus, highly sensitive optical sensors are promising for qualitative and quantitative analysis of harmful substances, including biochemical substances [6][7][8]. The combination of numerical and analytical methods can increase the efficiency of calculations performed to model real systems [9] and their practical improvement. Computer simulation methods designed to calculate the characteristics of these devices and the precise selection of their parameters require accurate calculation of highfrequency processes occurring in signal circuits [10], and refined models of electromagnetic oscillation propagation can solve this problem.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Propagation of Electromagnetic Oscillations by the Method of the Modified Equation of the Telegraph Line

Politansky

Nytrebych

Petryshyn

et al. 2021

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The article considers the physical processes associated with the propagation of electromagnetic oscillations in a long line, the size of which is the same or slightly greater than the length of the electromagnetic wave (not more than ten times). As a research method, the differential-symbolic method is used, which is applied to the modified equation of the telegraph line. The boundary conditions for the two-point problem as well as additional parameters that are coefficients for the first derivatives in terms of coordinate and time in comparison with the classical equation of the telegraph line are considered as parameters for controlling the process of propagation of electromagnetic oscillations. Based on the differential-symbolic method, the boundary conditions of the two-point problem are found, under which the most characteristic oscillatory processes are realized in a long line. Based on the research, it is possible to draw conclusions about the effectiveness of analytical methods for the analysis of specific technical objects and control of the processes that take place in them.