The electrical parameters of the semiconductor-metal phase transition in vanadium dioxide nanostructures synthesized by chemical vapor deposition on a silicon substrate (100) and decorated with gold nanoparticles with a surface concentration from 3∙109 to 3∙1010 cm–2 are studied. X-ray phase analysis revealed that the synthesized nanostructures of vanadium dioxide contain a monoclinic M1 phase undergoing a phase transition at a temperature of about 68 °C. The morphology of the surface of vanadium dioxide nanostructures coated with gold nanoparticles was studied using a scanning electron microscope and an atomic force microscope. The characteristics of the temperature phase transition of the initial nanostructures and nanostructures decorated with gold nanoparticles are determined. The temperature dependence of the resistance near the phase transition point of the initial nanostructures showed that the resistance jump is about four orders of magnitude, which confirms their high quality. It is shown that an increase in the surface concentration of gold particles to a value of 3∙1010 cm–2 increases the conductivity of vanadium dioxide at room temperature by about two times, and shifts the phase transition temperature by 5 °C: from 68 °C to 63 °C. Optical switching in vanadium dioxide with an array of gold particles with a size of 9 nm is considered by numerical modeling methods. It is established that the response of the electromagnetic wave from the VO2 material during the phase transition is enhanced due to the excitation of localized plasmon resonance in gold nanoparticles and reaches a local maximum in the region of 600 nm. Additionally, this effect is enhanced at angles of incidence near the pseudo-Brewster angle for vanadium dioxide. The considered hybrid VO2–Au nanostructures are promising as basic nanoelements for next-generation computers, as well as for ultrafast and highly sensitive sensors.

Oxidation scanning probe lithography is one of the most promising techniques for nanostructuring. Vanadium oxides constitute a class of functionally rich materials that are promising for various practical applications and have unique physical properties. Currently, the formation of nanocrystals and nanostructures with well-defined dimensions is a challenging task. This study presents a detailed investigation of the processes involved in oxidation scanning probe lithography on the surface of thin amorphous vanadium oxide (VOx) films. It was shown that the oxidizable regions of the film transform into a water-soluble vanadium pentoxide (V2O5) in accordance with classical redox reactions. The oxidation kinetics was shown to be consistent with the CabreraMott model. Dissolving the oxidized regions in water resulted in the formation of nanohole arrays with defined sizes in VOx films. Nanostructures with a depth of less than 0.3 nm and lateral dimensions of less than 50 nm were obtained at relative humidity of about 10 %. It was demonstrated that VOx films about 10 nm thick can be completely oxidized in local areas, enabling the formation of isolated nanostructures. The considered method of nanostructuring VOx is promising for the formation of novel photonic and nanoelectronic devices.

Liquid crystal cells, in which the planar director orientation is specified by SU-8 polymer films treated by the stamp nanoprinting method, have been studied. The orienting film surface after texturing represents a comb-shaped lattice, the profile of which depends on the processing temperature. In cells filled with nematic LC E7, a homogeneous orientational structure with a small number of surface linear defects on both substrates is formed. These defects do not appear in LC cells with asymmetric substrates, when one of them is coated with an SUshown that the director pre-tilt angle on the studied SU-8 films is close to zero and the films set a strong polar anchoring energy for the nematic E7. The results obtained are of interest for the development of methods for manufacturing LC devices using technologies for nanoprinting of orienting polymer films.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

The discovery of new low-dimensional materials formed by splitting known bulk crystals into separate elementary layers has enabled future realization of still undiscovered potential of long-studied materials. High-resistivity two-dimensional films obtained by splitting ionic layered crystals are of great interest for creating new vertical van der Waals heterostructures. For unveiling the potential of using two-dimensional monocrystalline films of CdWO4 and ZnWO4, it is necessary to gain a more penetrating insight into the processes that occur on the freshly splitted surface of the crystals. In the present study, for the first time we investigated the effect of AFM probe on the (010) surfaces of freshly splitted CdWO4 and ZnWO4 single crystals. It is shown that the observed "protruding areas" on the splitted surfaces of these crystals are of a complex nature, and they are mainly related with the transfer of charges, as well as with the formation of complete bonds on the surface of the broken crystal lattice of examined crystals. The charge spots observed on the splitted surface of the crystals arise as a result of local charging by AFM probe. As a result of charge diffusion, as well as under the influence of ambient medium, the complete dissipation of charges occurs in less than 2 h.

A new approach for the formation of free-standing vertical resistive nanoswitches based on VO2 nanocrystals (NCs) with embedded conductive nanosharp Si tips is demonstrated in the present article. This approach consists in the chemical vapor deposition synthesis of VO2 NCs on the apices of sharp conductive nanotips formed on a Si substrate by the standard methods of planar silicon technology. The amplification of the electric field and current density at the tip apex inside a high-quality VO2 NC leads to a record-breaking reduction of switching voltage (by a factor of 20-70) in comparison with conventional geometry devices with planar contacts. Our pulse measurements showed that the extremely low energy equal to 4.2 fJ was consumed for the switching in such NCs, and the total number of switching cycles in one NC without degradation exceeded 10(11). The proposed approach can be extended to the formation of large arrays of such nanoswitches. We showed that periodic arrays of individual VO2 NCs were selectively synthesized on sharp Si tips. The nanosizes of the switches, ultra-low power consumption for switching and the possibility of forming dense arrays of such objects make the fabricated nanoswitches promising devices for future neuromorphic systems.

The band structure and electric properties of films created from a partially fluorinated graphene suspension are analyzed in this paper. As may be inferred from the structural study, graphene islands (quantum dots) are formed in these films. Various types of negative differential resistance (NDR) and a step-like increase in the current are found for films created from the fluorinated graphene suspension. NDR resulting from the formation of the potential barrier system in the film and corresponding to the theoretical prediction is observed for a relatively low fluorination degree. The origin of the NDR varies with an increase in the fluorination degree of the suspension. The observation of NDR in the fluorinated films widens the range of application of such films, including as active device layers fabricated using 2D printed technologies on rigid and flexible substrates.

Titanium dioxide (anatase, a-TiO2) films have been prepared by electron beam sputtering of a TiO2 target in reactive atmosphere and their structural, microstructural, and optical properties were evaluated by reflection high- energy electron diffraction (RHEED) and x-ray diffraction (XRD) analyses, atomic force microscopy (AFM), and spectroscopic ellipsometry (SE). Different reflection models for determination of film optical parameters were tested and compared. The dispersive optical parameters were defined using the Tauc–Lorentz model by SE in the photon energy range of E = 1.12–4.96 eV. The films were transparent at E < 3 eV, but noticeable absorption was detected at E > 3 eV. The bandgap was estimated at the level of E g ≈ 3.44 eV.

Structural and optical properties of films and particles prepared from partially fluorinated graphene suspensions were examined. Photoluminescence (PL) coming from partially fluorinated graphene suspensions (quantum dots with fluorinated edges) and films prepared from such suspensions was observed. The necessary conditions for excitation of photoluminescence and PL emission spectra consisting of one to three PL features with energies 2.65, 2.81, and 2.97 eV have been identified. The PL emission spectra were compared with the spectrum of the size quantization levels in partially fluorinated graphene and few-layer graphene films. The spectrum of levels was revealed from the charge deep-level transient spectroscopy measurements taken during studying the electron capture and the emission processes in such films. The PL emission spectra were interpreted with the assumption that fluorination of graphene suspensions leads to formation of quantum dots within graphene. A qualitative model was proposed to explain the observed correlation between the PL emission spectrum and the energy spectrum of graphene quantum dots embedded in a fluorinated graphene matrix.

Metrology is essential for nanotechnology, especially for structures and devices with feature sizes going down to nm. Scanning probe microscopes (SPMs) permits measurement of nanometer- and subnanometer-scale objects. Accuracy of size measurements performed using SPMs is largely defined by the accuracy of used calibration measures. In the present publication, we demonstrate that height standards of monolayer step (similar to 1 and similar to 0.6 nm) can be easily prepared by cleaving Bi2Se3 and ZnWO4 layered single crystals. It was shown that the conducting surface of Bi2Se3 crystals offers height standard appropriate for calibrating STMs and for testing conductive SPM probes. Our AFM study of the morphology of freshly cleaved (0001) Bi2Se3 surfaces proved that such surfaces remained atomically smooth during a period of at least half a year. The (010) surfaces of ZnWO4 crystals remained atomically smooth during one day, but already two days later an additional nanorelief of amplitude similar to 0.3 nm appeared on those surfaces. This relief, however, did not further grow in height, and it did not hamper the calibration. Simplicity and the possibility of rapid fabrication of the step-height standards, as well as their high stability, make these standards available for a great, permanently growing number of users involved in 3D printing activities. (C) 2017 Elsevier B.V. All rights reserved.

Here we describe a method of forming large arrays (up to 109 pieces) of free magnetic Ni-nanodisks 50 nm thick coated on both sides with layers of 5 nm thick Au. The antitumor effect of the magnetic nickel gold-coated nanodisks and DNA aptamer conjugates was evaluated in vivo and in vitro. Under the influence of rotating magnetic field, the studied nanodisks can cause the death of Ehrlich ascites carcinoma cells.

High-quality Pb2MoO5 crystals have been grown by the LTG Cz method.

Stable colloidal dispersions of niobium chalcogenides NbQ(2) and NbQ(3) (Q = S, Se) in organic solvents - CH3CN, dmf, (PrOH)-Pr-i, EtOH, EtOH/H2O (vol.1/1), n-BuOH were prepared by ultrasonication. According to DLS and AFM data the particle size distributions in the dispersions are rather wide: particle sizes vary from 70 to 400 nm, and the mean sizes are in range of 150-200 nm. DLS polymodal and monomodal analyses were carried out for the colloidal dispersions of NbQ(2) and NbQ(3) (Q = S, Se) in acetonitrile. The particles diffusive Brownian motion in the acetonitrile colloidal dispersions is best described by diffusion of disk-shaped particles with monomodal distributions for NbQ(3) and bimodal distributions for NbQ(2). A series of thin films prepared from the colloidal dispersions show that the particles retain their original crystal structures, at the same time strong texturing of the films appears. (C) 2014 Elsevier B.V. All rights reserved.

Conductive islands (quantum dots) of graphene and few-layer graphene in a fluorinated graphene matrix were produced by chemical functionalization of graphene in aqueous hydrofluoric acid. The structures formed were investigated by measuring the current-voltage characteristics and by means of an atomic-force microscope used to measure the surface topography and lateral forces. The presence of conductive islands in the fluorinated matrix was shown, and their sizes were determined.

The objective of this study is to compare the results of transferring graphene and few layer graphene (FKG) up to 5 nm thick, grown by chemical vapor deposition (CVD) at a reduced pressure to a SiO 2 /Si substrate using four different polymer films. The chosen transfer methods are based on the most promising (according to published data) materials: polymethyl methacrylate, polydimethylsiloxane, thermoscotch, and polycarbonate. It is shown that the most promising transfer method (minimum resistance and maximum carrier mobility) lies in the use of polycarbonate thin films with their dissolution in chloroform. In this case, the following parameters are steadily obtained: the graphene and FLG resistance is 250–900 Ω/□ and the carrier mobility is 900–2500 cm 2 /(V s).

Bulk NbS3and NbSe3were stably dispersed in a number of organic solvents to yield colloids containing thin well-crystallized nanoribbons of NbS3and NbSe3.

Special high-resistive substrates for graphene sheets are suggested with the aim of providing high conductivity and mobility of charge carriers in graphene. The substrates were created from N-methylpyrrolidone-intercalated few-layer graphene (FLG) using anneals given to FLG samples in the temperature range 100-180 degrees C. Structures containing a highly conductive single-layer graphene on an atomically flat, high-resistive substrate were produced by recovering the top-layer conductivity. The obtained structures have potential in electronic applications due to a high carrier mobility (up to 16 000-42 000 cm(2) V-1 s(-1)) and strong gate-voltage-induced modulation (by 4-5 orders of magnitude) of the current in the top graphene layer. The strong gate-voltage-induced modulation of the current clearly demonstrated that the top layer was chemically modified graphene. The possibility of governing the surface conductivity in the described structures offers a unique tool for two-dimensional nanodesign.