Using a high-resolution X-Ray diffraction measurement method, the surface acoustic waves (SAW) propagation in a graphene film on the surface of a Ca 3 TaGa 3 Si 2 O 14 (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here we show for the first time that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

Luminescence properties of ZnO films, which have been epitaxially grown on c-sapphire (0001) substrates by plasma-assisted molecular beam epitaxy, are investigated by means of different excitation sources and their measurement conditions. With the increase of measurement temperature, photoluminescence spectra clearly present, the appearance of different bound-exciton peaks (I10 line) with an abrupt increase of emission intensity at the measurement temperature of 30-50K. Hypothetical explanations on the basis of thermalization effects, vibronic/rotational resonance states, and the involvement of the B-valence level in emission are given. In cathodoluminescence (CL), the deep level emission intensity was enlarged with the electron beam penetration depth due to the higher defect density near the interface between ZnO and the sapphire. From the CL image of the ZnO film, the dislocation density was estimated as 6×108-3×109∕cm2. The lasing phenomenon was observed at the threshold power density of 1.3MW∕cm2 at 300K.

Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

An anomalous proximity effect was observed in coplanar Nb-BiSb-Nb junctions. The effect consists of a considerable increase of the critical current with an increase in the distance between the superconducting electrodes. The effect is explained by the quantum character of Cooper pair transport through the normal region. Some advantages of the application of such junctions are discussed. [S0031-9007(96)

Because of their unique atomic structure, 2D materials are able to create an up-to-date paradigm in fundamental science and technology on the way to engineering the band structure and electronic properties of materials on the nanoscale. One of the simplest methods along this path is the superposition of several 2D nanomaterials while simultaneously specifying the twist angle between adjacent layers (θ), which leads to the emergence of Moirésuperlattices. The key challenge in 2D nanoelectronics is to obtain a nanomaterial with numerous Moirésuperlattices in addition to a high carrier mobility in a stable and easy-to-fabricate material. Here, we demonstrate the possibility of synthesizing twisted multilayer graphene (tMLG) with a number of monolayers N L = 40−250 and predefined narrow ranges of θ = 3−8°, θ = 11−15°, and θ = 26−30°. A 2D nature of the electron transport is observed in the tMLG, and its carrier mobilities are close to those of twisted bilayer graphene (tBLG) (with θ = 30°) between h-BN layers. We demonstrate an undoubtful presence of numerous Moirésuperlattices simultaneously throughout the entire tMLG thickness, while the periods of these superlattices are rather close to each other. This offers a challenge of producing a next generation of devices for nanoelectronics, twistronics, and neuromorphic computing for large data applications.

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A new approach to the fabrication of model structures for nanoelectronics with characteristic sizes down to 10 nm is proposed. The approach consists in electron-beam-induced fabrication of self-supporting structures of nanometre sizes in a through slit formed in the substrate, followed by the deposition of a required material onto the structure, which serves as an active layer in a nanometre-scale device. Features of the fabrication steps are discussed. Bismuth nanobridges were fabricated and their voltage-current characteristics were measured, which demonstrated features of electron transport in these bridges connected with their small sizes and inner structures.

Extraordinary Hall effect probes with 160 nm × 160 nm working area were fabricated using photo- and electron-beam lithographic procedures with the aim of direct measurements of MFM cantilever tip magnetic properties. The magnetic field sensitivity of the probes was 35 Ω T(-1). Magnetic induction of the MFM cantilever tips coated by Co and SmCo films was measured with the probes. It was shown that the resolution of the probes was of the order of 10 nm.