[en] Numerical modeling results indicate that cadmium vaporization caused by nanosecond pulses of a ruby laser has a significant effect on the dynamics of phase transitions in the near-surface region of CdTe and leads to surface cooling of the material, resulting in a nonmonotonic temperature profile, with a maximum at a depth of about 20 nm. At incident energy densities above the threshold for CdTe melting, the molten zone forming below the surface layer extends both toward the surface and into the bulk of the semiconductor. Cd vaporization and the diffusion of Cd and Te in the melt give rise to tellurium enrichment in the near-surface region. Taking into account the dependences of the crystallization temperature and the latent heat of the phase transition on the Cd and Te concentrations in the melt, a reasonable agreement is achieved with experimental data on the effect of incident energy density on the time during which a molten layer is present in CdTe

[en] A numerical simulation of the influence of KrF excimer laser nanosecond radiation (λ = 248 nm, τ = 20 ns) on phase transitions in cadmium telluride has been carried out taking into account diffusion of components in the melt and evaporation of components from the surface. It is shown that as a result of evaporation and diffusion of cadmium telluride components, the near-surface region is enriched with tellurium. The obtained melting threshold value of energy density 0.05 J/cm² is in a reasonable agreement with experimental data

[en] Original design of the antenna type bolometer receiver for the electromagnetic waves of mid-infrared spectral range is proposed. It is shown that the antenna implementation of an uncooled receiver of specified radiation in the form of double-threaded helix and location of the microresonance structures along the two outer sides of a thermal element in a strictly geometric pattern can achieve return loss of – -10.95 dB, the standing wave ratio - 1.79 and conversion efficiency - ~ 92%. (authors)

[en] The results of numerical simulation of influence of nanosecond radiation of ruby laser have shown that the process of evaporation greatly affects the dynamics of phase transitions in the near-surface region of CdTe. Intensive evaporation results in surface cooling of the material, forming a nonmonotone temperature profile with maximum temperature at the depth of ∼ 20 nm from the surface. The melt formed under the surface at energy density of radiation exceeding threshold value extends in both directions to the surface and to the volume of semiconductor. As a result of evaporation and diffusion of components of cadmium telluride in the melt, superficial area is enriched with tellurium. (authors)

[en] An original design of a Schottky diode with beamed outputs is proposed. It is shown that the optimization the sizes of its elements and location of the periodic lattices in the layer of elastic dielectric can reach the reflection losses -38.81 dB, conversion efficiency 97.32 % and resonance frequency detection of 36.5 THz. (authors)

[en] A numerical simulation of the dynamics of phase transitions induced by nanosecond pulsed radiation from a ruby laser in CdTe has been carried out. It is shown that evaporation of Cd atoms results in cooling of the surface; consequently, a nonmonotonic profile of the temperature field is formed, with the maximum temperature being attained in the bulk of the semiconductor at a distance of about 10-30 nm from the surface. At radiation energy densities above the threshold, the molten state formed under the surface extends both to the surface and into the depth of the semiconductor. Crystallization also proceeds in two directions, namely, from the surface into the depth of the samples due to the growth of nucleation centers in the melt, which is highly depleted in Cd atoms under the conditions of intense heat removal, and from the substrate to the surface due to epitaxial growth

[en] Mathematical modeling of the thermal detector, containing coating absorbing infrared radiation and thermally coupled sensitive element, which constitute microresonator, fulfilling in shape of the closed optical silicon waveguide, are performed. It is shown that the utilizing nontraditional absorbing coatings, made, for example, from the metal-dielectric materials makes it possible to attain the simultaneous increase speed and sensitivity of pixel-infrared detector. Critical parameters of a pixel-detector, providing transformation of the infrared radiation in the spectral range: from 2 μm to 20 μm to the radiation with a wavelength of 1.5 μm are calculated. Principal parameters of a pixel-infrared detector for two types of used absorbing coatings: gold black - frequency of the survey 50 Hz, energy of infrared radiation on the one information channel 7,4 · 10^-11 J and SiO_x < Fe> metal-dielectric film with the ratio: SiO_x (77 %) and Fe (23 %) - frequency of the survey 100 Hz, energy of infrared radiation on the one information channel 2.45·10^-11 J are obtained on the basis of the numerical solution of unsteady one-dimensional heat equation. (authors)

[en] Numerical simulation of melting and solidification processes induced in CdTe by nanosecond radiation of ruby laser (λ = 694 nm, τ = 20 and 80 ns) and KrF excimer laser (λ = 248 nm, τ = 20 ns) taking into account components diffusion in melt and their evaporation from the surface has been carried out. Cd atoms evaporation has shown to essentially affect the dynamics of phase transitions in the near-surface region. Thus, in the case of the influence of ruby laser irradiation intensive surface cooling results in the formation of nonmonotone temperature profile with maximum temperature in semiconductor volume at the distance of ∼20 nm from the surface. The melt formed under the surface extends both to the surface and to the semiconductor volume as well. As a result of cadmium telluride components evaporation and diffusion in the melt the near-surface region is enriched with tellurium. The obtained melting threshold value of irradiation energy density is in a reasonable agreement with experimental data

[en] A numerical simulation of the composition modification induced in ZnSe by nanosecond irradiation of the KrF excimer laser (λ = 248 nm, τ = 20 ns) has been carried out. Intensive evaporation of components has shown to results in the material surface cooling and forming a nonmonotone temperature profile with maximum temperature in semiconductor volume at the distance of ∼6 nm from the surface. As a result of evaporation and diffusion of components formation of the near-surface layer with nonstoichiometric composition takes place and enrichment of selenium reaches maximum value not on the surface, but in the semiconductor volume