In this work we present an automatic thermoregulation system for biosensors based on field-effect transistors with a nanowire channel, which provides full control on the required temperature regime in bioanalytical analises. The system elements, including field-effect transistors with a nanowire channel, temperature sensors and heaters, were fabricated on a single silicon cristal using electron beam lithography, reactive ion etching and high-vacuum deposition techniques. Unicue electronics have been developed to control and maintain temperature. The dependence of thermometer readout on heating power was measured, which is in good agreement with the results of numerical simulation. A demonstration of a thermoregulation system with PID-feedback was carried out, ensuring the establishment of a desiered temperature in the range of 30-70◦ C in 18 s in liquid. A demonstration of a thermoregulation system for detecting nucleic acids was carried out using synthetic single-stranded DNA, which is a gene fragment from the bacterium Escherichia coli. The minimal detectable response was observed for a sample with a concentration of 3 fM.

We present a CMOS compatible technique for fabrication a sensor system based on field-effect transistors with a nanowire channel with an integrated thermoregulation elements. The proposed system provides the necessary temperature regimes for many bioanalytical studies. Field-effect transistors with a nanowire channel were fabricated using of reactive-ion etching of the upper layer of a silicon on insulator through a mask formed by electron beam lithography. Titanium thermoresistive strips for temperature control were located on the surface of the chip nearby to the nanowire transistors. Their fabrication is carried out simultaneously with the formation of contact pads to the transistor electrodes, which made it possible to avoid additional technological steps. A demonstration of a system with a built-in temperature controller for the determination of nucleic acids was carried out on model oligonucleotides. Increasing the operating temperature of the device to the ranges at which DNA hybridization occurs most efficiently allows increasing specificity and avoiding false positive results, as well as reducing analysis time. The possibility of heating up to 85–90∘C allows you to reuse such devices.

We present an investigation of the superconducting properties of thin YBa2Cu3O7-x (YBCO) films grown on [001] single-crystalline quartz substrates by pulsed laser deposition (PLD) technique. The growth of YBCO on quartz is challenging due to large crystal lattice mismatch between YBCO and quartz. We obtained highly c-oriented textured films with superconducting transition at about 85 K, transition width of 1 K, and critical current density j(c) approximate to 10(4) A cm(-2) at 77 K. Analysis of the temperature dependences of the resistivity and current-voltage char- acteristics has shown the presence of the thermally-assisted flux flow at temperatures above 70 K. From the temperature and magnetic field dependences of critical current, vortex activation energy, U-0(H), was estimated for both parallel and perpendicular orientation of magnetic field. Second critical field, H-c2(0), was estimated from extrapolation of the H-c2(T) dependences. The obtained results are an important step towards realization of YBCO thin films on amorphous silica fibers for the third generation (3G) of the HTS long wire with low losses in alternative current applications.

Here we present CMOS compatible fabrication methods and the results of an experimental study of single-atom single-electron transistors made from silicon on insulator and based on various dopant atoms. Transistors with channels doped with arsenic (As), phosphorus (P), gold (Au) and potassium (K) atoms were fabricated and studied. Two methods for fabricating of experimental transistor structures are presented. The first method (As, P transistors) used a inhomogeneously doped in depth silicon layer and controlled reduction of the size of the transistor channel in several cycles of isotropic reactive-ion etching. The second method (Au and K transistors) used an undoped silicon layer and the subsequent implantation of dopant atoms into a preformed transistor channel. Dopant electron and hole levels of Au and K atoms in silicon are located near the middle of the silicon band gap, which provides a small effective size of the dopant charge center and, as a result, a high value of the charge energy and operating temperature of the transistor compared to the traditional dopants (P, As, Sb, B). The values of the charge energy of the Au and K transistors, which were estimated from the measurements (Ec ≥ 150 meV), are much higher than those of the As and P transistors (Ec < 30 meV). Important advantages of the proposed methods are: controlled implantation of various impurities and possibility to combine etching and implantation cycles during sample preparation.

The binding to Lon protease through biotinylated aptamers whose structures contain G-quadruplex fragments with magnetic nanoparticles (MNPs) functionalized by streptavidin was investigated. The conditions of binding of target aptamers to MNPs are met. The resulting complexes are proposed for detection of Lon protease in different biological sources and for constructing a novel biomagnetic nanosensor immunoassay system.

We present the results of an experimental study of electron transport through individual phosphorus dopants implanted into a silicon crystal. We developed an original technique for single-electron transistor fabrication from silicon-on-insulator material with an island formed by single phosphorus atoms. The proposed method is based on well-known CMOS compatible technological processes that are standard in semiconductor electronics and may be used in most research groups. The large Coulomb blockade energy value of the investigated single-electron transistor (∼20 meV) allows one to observe single-electron effects in a wide temperature range up to 77 K. We measured and analyzed stability diagrams of fabricated experimental structures. We demonstrated a single-electron transistor with controllable electron transport through two to three phosphorus dopants only.

Results of investigations using X-ray diffraction and scanning electron microscopy of composite materials made from YBa2Cu3Oy films sputtered (using various regimes) onto a substrate of amorphous quartz with a platinum buffer layer, have been given.

The simple variant of the SQUID-based readout system for a strap-down gyroscopic inertial navigation system was created and tested. A voltage-to-angle transfer function close to 6 V/deg was measured. A drift rate less than 4 mV during 450 s was observed in the developed experimental stand. A noise level is strongly influenced by gyroscope's electrostatic support plates.

We analyzed the sensitivity of a separationless immunoassay scheme using functionalized magnetic nanoparticles (MNPs) and a sensitive HTS SQUID magnetometer. The signal of a 100 μL sample at a concentration of 1 mg/mL and field of 7.5 nT was 20 mΦ 0 . This makes it possible for the sensitivity to be within the range of 50 ng/mL at the required time of up to 100 s per a point in the frequency spectrum.

The internal structure and orientation of thin (150–300 μm) flexible Al2O3 fibers used as substrates for third-generation high-temperature superconducting wires are studied by different methods. It is shown that using scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction, one can reliably determine the position of the \((1\bar 102)\) plane, on which good YBa2Cu3O y films can be grown.

A composite superconductor SiO 2 /YSZ/CeO 2 /YBa 2 Cu 3 O y with a critical current density of 7 × 10 4 A/cm 2 has been prepared by laser ablation. Small hills enriched in copper and oxygen on the surface of the deposited films have been detected using scanning electron microscopy. A grain structure (sizes of 0.2–0.3 μm) and a system of twins ~400 Å in width have been detected in the superconducting film using transmission electron microscopy. Such a structure and high (001) texture of the film provide the noted critical current density.

We used aptamers, which are functional equivalents of antibodies, in order to develop a nanosensor immunoassay system based on magnetic nanoparticles and a SQUID magnetometer. Selection was used to obtain DNA aptamers to interleukin-6; their affinity to the target protein was characterized by surface plasmon resonance. It was shown that the biotinylated aptamer binds to magnetic nanoparticles that were functionalized with streptavidin.

The problem of the fabrication of third-generation high-temperature superconductors (HTSCs) that are designed for the transmission of electric energy and the creation of nanoelectronic devices is studied in this work. The issues of the fabrication of dielectric substrates for the third generation wires are considered. The technology of HTSC film deposition on the quartz substrates is presented. Complex studies of sputtering of the buffer and superconducting YBa2Cu3O7 − δ (YBCO) layers were performed. The results of studies of electrophysical properties of the HTSC films on the quartz substrates are discussed.

We propose an analytical parametric model for defining energy spectra of nanoparticles with a number of atoms of up to 3,300. This allows us to perform Monte-Carlo simulations for single-electron transistor (SET) based on gold nanoparticles with a size of up to 5.2 nm at temperatures from 0.1 to 300 K. At the first step, energy spectra were calculated for isomers of gold nanoparticles, consisting of up to 33 gold atoms using methods of quantum mechanics: density functional theory (DFT) with LANL2DZ basis set for “geometry” optimization; unrestricted Hartree–Fock method (UHF)x with SBKJC basis set to evaluate energy parameters of nanoobjects, which include gold atoms with many electrons. It was found that the general structure of the energy spectra changes unsignificantly if the number of atoms is greater than 27. Moreover, the size of the energy gap and the position of energy levels in it are linear functions of one parameter—the total electric charge of the nanoparticle. These features of energy spectra allowed us to perform calculations of the transport characteristics for a real SET using gold nanoparticle as a central conducting island.

An electron transport through the extremely small gaps (1–5 nm wide) formed in narrow and thin gold nanowires by the electromigration method is studied in this work at various temperatures. A careful investigation of the final stage of a gap formation has shown a quantum character of a nanowire conductivity on this stage. Analysis of the electron transport characteristics through the resulting gaps was carried out. It shows that regimes of both a direct tunneling between electrodes and a “cold” emission into a barrier region were realized. Significant reduction of electron work function for gold electrodes of prepared gaps is revealed.

The Y3d, Ba3d 5/2, Cu2p 3/2, and O1s X-ray photoelectron spectra of thick (600 nm) superconducting YBa2Cu3O7 − δ films deposited on textured Ni-W substrates with Y2O3 + ZrO2 and CeO2 buffer layers have been studied. It has been established that, after the mechanical removal of surface layers with a diamond scraper (and as the analyzed region of the film approaches the interface), a decrease in the oxygen content leads to a decrease of the orthophase fraction and an increase of the tetraphase and Cu+ ion fractions. This is caused by the presence of elastic stresses in the superconducting film due to the lattice misfit between the phases making up a composite sample. These stresses prevent oxygen diffusion involved in oxidizing annealing. The spectra of the superconducting film have not revealed signals generated by elements of the substrate and buffer layers.