Alexey Kazakin

Nickel oxide is a promising material for transparent electronics applications. This semiconductor demonstrates the possibility of modifying its physical properties depending on the method of growth and subsequent processing. Here the effects of the discharge power are reported during reactive dc magnetron sputtering, as well as the modes of subsequent annealing of NiO films, on their structural, electrical, and optical properties. NiO films are annealed at various temperatures both in an oxygen‐containing environment and under vacuum conditions. Deposited NiO films have a polycrystalline structure with a preferred orientation (200) for the low discharge power mode and (111) for the high discharge power mode. However, obtained NiO films exhibit crystallinity improvement after annealing. The presence of both Ni²⁺ and Ni³⁺ oxidation states in the deposited films is found. In addition, it is shown that the relative carrier concentration (Ni³⁺/Ni²⁺ peak area ratio) can be controlled by choosing the NiO film preparation mode. The trend in this ratio corresponds to the trend in film conductivity and the number of free‐charge carriers. The deposited films are semitransparent, and the estimated optical bandgap of NiO is in the range from 3.50 to 3.74 eV.

The article is devoted to solving the problem of ensuring accurate control of the operating temperature of alkali vapor cells for quantum frequency standards and magnetometers in order to increase the stability of their parameters. For this purpose, a low-magnetic electric heating chip, containing a temperature control system, which consists of a thin-film heater and a temperature sensor, has been developed and manufactured by MEMS technology. The system has such a design that the magnetic fluxes generated by the electric currents passing through its individual elements mutually extinguish each other. The heating chip and the cesium vapor MEMS cell were integrated into the physical package of the atomic clock. The magnitude of the magnetic field induced in the center of the MEMS cell was estimated by measuring of the atomic clock resonant frequency shift at different heater currents. It was found that the dependence of the parasitic magnetic flux density on the heater current has a linear character with a coefficient of 2.1 nT/mA.

This paper investigates the optical and electrical properties of ITO films for their application as a transparent contact electrode to NiO films. The films were fabricated by magnetron sputtering at various parameters of the discharge power and oxygen content in the working gas mixture. Structural analysis showed an increase in the crystallinity of the films during their subsequent annealing. The films demonstrate high conductivity and transparency with an absorption edge higher than that of NiO films. The results of the study show a high potential for using ITO films to create a transparent electrode to NiO layers.

In this paper, we propose a method for the formation of efficient photoconverters which optical band gap decreases due to the introduction of impurities (gold nanoparticles) into the oxide. Gold nanoparticles can act both as noticeable levels in the band gap and as plasmonic particles. The use of 2D geometry in this case allows you to significantly increase the effective transformation surface. Photo-induced current transfer through nanocomposite structures consisting SiO 2 layers activated with gold nanoparticles (AuNP) are under investigation. AuNPs are situated on top of SiO 2 nano-pillars. Nano-pillar array with AuNPs is prepared by previously described two-step technique using plasma etching. Optical and electric characteristics of these structure are investigated.

In this work, we studied the influence of technological parameters of plasma chemical etching of silicon on silicon etching rate, photoresist etching rate, etching selectivity of silicon in relation to a photoresist, and sidewall angle of etched structures. It was found that the silicon etching rate increases with raising percentage of SF6 in the gas mixture (25%–50%), pressure (1–2.5 Pa), high-frequency (HF) power (1000–2000 W), and bias voltage module (15–75 V) and decreases with a raising total flow rate of the gas mixture (5–35 SCCM) due to the increasing passivation efficiency of the sample surface. The etching selectivity increases with a raising percentage of SF6 and pressure and decreases with the raising total gas flow rate, HF power, and bias voltage module due to different influences of technological parameters on the photoresist etching rate. In addition, based on the obtained results, a common regularity between the sidewall angle and the optical emission spectra was revealed. The method of in situ diagnostics was proposed, namely, controlling the sidewall angle by a ratio of emission intensities of a carbon line (517.1 nm) to a fluorine line (685.8 and 703.9 nm) designated as parameter X. It was found that the sidewall angle of etched structures takes certain values depending on the value of the X parameter. The ranges of X values at which the sidewall angle is acute, right, and obtuse were estimated. So, at values of X from ≈0.15 to ≈0.35, an acute angle (from 81° ± 0.5° to 89° ± 0.5°) is obtained; at X from ≈0.35 to ≈0.42, a right angle is obtained (90° ± 0.5°); and at X from ≈0.42 to ≈0.75, the values of the sidewall angle are in the range from 91° ± 0.5° to 94° ± 0.5°, no matter which technological parameters were set. Experiments were conducted for etching windows with linear dimensions from 0.5 × 20 to 2 × 20 mm.

In this work, a versatile method to increase the optical response of oxide nanostructures is described. Thin TiO₂ films with buried gold nanoparticles (TiO₂-AuNP) were synthesized on a crystalline Si surface. The localized surface plasmon resonance reflection maximum is formed around 720–750 nm. Current-voltage characteristics of planar structures formed by use of different contact materials were measured. Spectral features of an optical response of TiO₂-AuNP is discussed. The results obtained indicate a broad prospect of using the formed structures in the field of integrated optoelectronic devices.