S. A. Vitusevich

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The low-frequency 1/f noise characteristics of AlGaN/GaN high-electron-mobility transistors with gate length scaled down to 150 nm grown on sapphire by metalorganic chemical vapor deposition have been studied. Certain features of the 1/f noise have been revealed in these short-gate transistors. The low-frequency noise spectra show drastically different(More)
We report on the influence of low gamma irradiation (10(4) Gy) on the noise properties of individual carbon nanotube (CNT) field-effect transistors (FETs) with different gate configurations and two different dielectric layers, SiO2 and Al2O3. Before treatment, strong generation-recombination (GR) noise components are observed. These data are used to(More)
We report on experimental studies of high-field electron transport in AlGaN/GaN two-dimensional electron gas. The velocity–electric field characteristics are extracted from 10 to 30 ns pulsed current–voltage measurements for 4.2 and 300 K. An electron drift velocity as high as 1.7 3107 cm/s was obtained in the fields 150 kV/cm. Estimates of thermal budget(More)
The electrodynamic characteristics of a high-Q dielectric whispering gallery mode resonator in the form of a hemisphere positioned on an impedance plane were studied. The analysis of the anisotropic resonator was modeled using Maxwell equations and the impedance Leontovich boundary condition. The interaction coefficient A<sub>S</sub><sup>j</sup> of the(More)
Nonlinear properties of high-temperature superconducting (HTS) strongly coupled resonators at different input power have been investigated by measurements of the quality factor as a function of input power as well as by generation of the intermodulation distortion (IMD). The double-sided YBCO films on CeO2 buffered sapphire demonstrate advanced performance(More)
The photoresponsivity spectra of double-barrier resonant tunneling diodes have been measured in a wide range of light wavelength as well as applied voltage. The complex behavior of measured spectra is analyzed taking into account different channels for electron injection into the quantum well ~QW!. It has been shown that the photoresponse in the infrared(More)
We studied space-charge-distribution phenomena in planar GaN nanowires and nanoribbons (NRs). The results obtained at low voltages demonstrate that the electron concentration changes not only at the edges of the NR, but also in the middle part of the NR. The effect is stronger with decreasing NR width. Moreover, the spatial separation of the positive and(More)
In this paper we present fabricated Si nanowires (NWs) of different dimensions with enhanced electrical characteristics. The parallel fabrication process is based on nanoimprint lithography using high-quality molds, which facilitates the realization of 50 nm-wide NW field-effect transistors (FETs). The imprint molds were fabricated by using a wet chemical(More)
Studies of biochemical liquids require precise determination of their complex permittivity. We developed a microwave characterization technique on the basis of a high-quality whispering-gallery mode (WGM) sapphire resonator with a microfluidic channel filled with the liquid under test. A novel approach allows obtaining the complex permittivity of(More)