Arrays of vertically oriented carbon nanotubes (VOCNTs) with a height from 25 to 100 μ m and a specific resistance from 1.5 to 4 Ω cm have been grown by catalytic chemical vapor deposition on the Si/HfO _2 /Fe surface for the first time. The growth of VOCNTs on hafnium oxide is observed within a temperature range of 625-725 °C and does not occur at T≥ 750 °C. At the same time, the temperature dependence of the VOCNT growth rate is characterized by a value of ∼ 1.5 eV. Using high-resolution scanning electron microscopy and Raman spectroscopy, the predominance of nanotubes with diameters from 1 to 10 nm in the array is shown. It has been revealed that HfO _2 nanocrystallization during the annealing of substrates complicates the SEM analysis of catalytic Fe particles, whose size on the surface of initial amorphous HfO _2 is 2-5 nm.

Методом каталитического химического осаждения из газовой фазы впервые выращены массивы вертикально ориентированных углеродных нанотрубок (ВОУНТ) на поверхности Si/HfO2/Fe высотой от 25 до 100 мкм и удельным сопротивлением от 1,5 до 4 Ом · см. Рост ВОУНТ на оксиде гафния наблюдается в интервале температур 625-725 ° C, а при T ≥ 750 ° C не реализуется. При этом температурная зависимость скорости роста ВОУНТ характеризуется величиной ~1,5 эВ. С использованием высокоразрешающей сканирующей электронной микроскопии и спектроскопии комбинационного рассеяния света показано доминирующее присутствие в массиве нанотрубок с диаметрами от 1 до 10 нм. Обнаружено, что нанокристаллизация HfO2 при отжиге подложек затрудняет СЭМ-анализ каталитических частиц Fe, размер которых на поверхности исходного аморфного HfO2 составляет 2-5 нм. Using the catalytic chemical vapor deposition method, VACNT arrays with a height of 25 to 100 μm and a resistivity of 1.5 to 4 Ohm ⋅ cm have been grown for the first time on a Si/HfO2/Fe surface. The growth of VACNTs on hafnium oxide is observed in the temperature range T = 625-725°C, but is not realized at T ≥ 750 °C. In this case, the temperature dependence of the VACNT growth rate is characterized by a value of ~1.5 eV. Using high-resolution scanning electron microscopy and Raman spectroscopy, the dominant presence of nanotubes with diameters from 1 to 10 nm in the array is shown. It is found that nanocrystallization of HfO2 during annealing of substrates complicates the SEM analysis of catalytic Fe particles whose size on the surface of the initial amorphous HfO2 is 2-5 nm.

Using in situ reflection electron microscopy, transformations of Bi2Se3(0001) surface during In deposition have been studied. We first report the formation of an In-induced surface phase that precedes nucleation and growth of a layered In2Se3 at substrate temperatures around 400 degrees C. The surface phase nucleates on Bi2Se3(0001) terraces as islands having high In content and a height of 0.4 nm. During continuous In deposition, the area of these islands increases and suppresses Bi2Se3 sublimation from the regions covered by the In-induced surface phase. This locally suppressed sublimation and sublimation-induced ascending motion of Bi2Se3 atomic steps create multilayer triangular star-shaped islands.

In this paper, we study the emission spectrum of the photonic crystal slab (PCS) with embedded Ge/Si quantum dots using the original technique of a directional micro-photoluminescence (DPL). This technique is a powerful combination of two approaches to the experimental study of PCS. First, it allows to collect photoluminescence (PL) signal within small solid angles in the selected directions and thereby to study the dispersion dependence of PCS modes. Second, it gives the experimental opportunity to analyze the quality-factor change of observed PL peaks with an increase in the collection angle and allows us to find in the PL spectrum the high-quality modes, namely the bound states in the continuum. A comparison with theoretical dispersion dependencies of PCS modes calculated by the Fourier-modal method in the scattering matrix form demonstrates a clear correspondence between PCS dispersion curves and angular dependencies of observed PL peak positions. The obtained results indicate that the DPL technique can be successfully used both to visualize the photonic band structure and to determine the nature of the PCS modes.

This work is devoted to the development of a technique for obtaining an array of multi-walled vertically aligned carbon nanotubes (VACNT) with a thickness of up to 120 μm on Si/Al2O3/Fe substrates and to the study of their absorbing properties in the THz spectral region, as well as to the assessment of their prospects as a broadband THz radiation absorber based on calculations of the spectral dependence of absorption coefficient for traditional and inverted-type bolometric devices. It is shown that the absorption of the VACNT array transferred onto the Revalpha polymer substrate reaches 70–80% in the wavelength range of 40–200 µm. Calculations show that traditional bolometers with an absorber based on VACNT have the best sensitivity at wavelengths less than 100 μm, and inverted bolometers also having a VACNT layer have the best sensitivity at wavelengths exceeding 50 μm, which makes them complementary to each other.

The low-temperature linear and nonlinear transport on nanoperforated titanium nitride films is experimentally studied. A metallic Bose state is shown to appear in the system, and it transforms into a metallic state in a magnetic field. The linear and differential magnetoresistances of the system exhibit oscillations. A vortex Mott insulator was shown to transfer into a metallic state when a direct current passes through a film.

This work demonstrates the possibility of detection of DNA-oligonucleotide (oDNA) and microRNAs (miRNAs) extracted from blood plasma and associated with breast cancer (BC) in a buffer solution using the nanowire (NW) biosensor based on the silicon-on-insulator (SOI) structures. For biospecific detection, the NW surface was modified with oligonucleotide probes (oDNA-probes) complementary to the well-known miRNA sequence. It has been shown that the SOI-NW biosensor with immobilized oDNA-probes of this type can be used to detect complementary oDNA in a buffer solution with a concentration sensitivity of 10(-17) M. The study also demonstrates the use of such biosensor for detection of an increased level of miRNAs isolated from the plasma of breast cancer patients. Application of the NW biosensor enables to distinguish between patients with a diagnosis of breast cancer from those with ovarian cancer (OC) by the value of an increased miRNAs level in the blood plasma of breast cancer patients. (C) 2018 Elsevier B.V. All rights reserved.

In this chapter the ability to study atomic processes on the Si surface during sublimation, growth, oxygen etching, and gold adsorption by in situ ultrahigh vacuum reflection electron microscopy (a unique method developed in ISP SB RAS) are reviewed. Using this technique, a surface instability called the step-bunching phenomenon was discovered previously, it is however, still poorly understood due to many unknown parameters of adatom/advacancy step interactions. Observation of gold adsorption induced step-bunching depending on an annealing time at a temperature of T=900°C suggests that a surface-bulk defect exchange is also involved in the formation of instability. The dynamics of two-dimensional vacancy island formation on 120-µm step-free terraces shows that sublimation is defined by adatom detachment from steps up to a critical temperature of Tcrit~1180°C, while adatom diffusion length falls from ~55 (970°C) to ~7 µm due to recombination with the vacancies. At Tcrit>1180°C, sublimation is dominated by the straightforward evaporation of surface atoms reserving vacancies that interact with steps. From the studies of Si growth on the step-bunched Si(111)-(7×7) surface, a crucial role of step permeability in 2D island nucleation and growth (2DNG) kinetics has been revealed. Step permeability is a key factor in pyramid-like growth on terraces exceeding the critical width for 2DNG. We show that quantitative parameters of adatom/vacancy diffusion and their interactions with steps (Schwöbel barriers) can be determined.

A method for detection of cancer-associated protein D-NFATc1 in serum using nanowire (NW) biosensor based on field-effect nanotransistor is developed. Field-effect nanotransistor was fabricated on the basis of «silicon-on-insulator» structures. For the biospecific detection of target protein, the NW surface was modified with aptamers against the target protein. Using the 3 um-NW enabled to obtain stable source-drain characteristics and to register D-NFATc1 in serum at concentration of 2.5 x 1014 M in the mode of drain-source current vs. gate voltage characteristics measurements. Data collection in the mode of drain-source current vs. gate voltage characteristics measurements was carried out with the use of high-speed data collection system running TURBO NBS software.

The low-temperature transport properties of titanium nitride wires with the width comparable with or much larger than the superconducting coherence length are studied experimentally. It is shown that the reduction of the width of wires does not affect the transport properties at the temperatures above the superconducting transition temperature and electron transport in this temperature range is determined by quantum contributions to the conductivity from weak localization and electron–electron interaction. It is established that the reduction of the width of wires does not change the superconducting transition temperature but completely suppresses the topological Berezinskii–Kosterlitz–Thouless transition. It is found that the threshold magnetic field increases with a decrease in the width of wires.

The nanowire (NW) detection is one of fast-acting and high-sensitive methods allowing to reveal potentially relevant protein molecules. A NW biosensor based on the silicon-on-insulator (SOI)-structures was used for biospecific label-free detection of NFAT 1 (D-NFAT 1) oncomarker in real time. For this purpose, SOI-nanowires (NWs) were modified with aptamers against NFAT 1 used as molecular probes. It was shown that using this biosensor it is possible to reach the sensitivity of ~10(-15) M. This sensitivity was comparable with that of the NW biosensor with immobilized antibodies used as macromolecular probes. The results demonstrate promising approaches used to form the sensor elements for high-sensitive disease diagnostics.

The nanowire (NW) detection is one of the fast-acting and high-sensitive methods, which can recognize potentially relevant protein molecules. A NW-biosensor based on the silicon-on-insulator (SOI)-structures has been used for biospecific label-free real time detection of the NFATc1 (D-NFATc1) oncomarker. For this purpose, SOI-nanowires (NWs) were modified with aptamers against NFATc1 used as molecular probes. It was shown that using this biosensor it is possible to reach sensitivity of 10−15 M. This sensitivity was comparable to that of the NW-biosensor with immobilized antibodies used as macromolecular probes. The results demonstrate that approaches used in this study are promising for development of sensor elements for high-sensitive diagnostics of diseases.

A superconductor in a magnetic field acquires a finite electrical resistance caused by vortex motion. A quest to immobilize vortices and recover zero resistance at high fields made intense studies of vortex pinning one of the mainstreams of superconducting research. Yet, the decades of efforts resulted in a realization that even promising nanostructures, utilizing vortex matching, cannot withstand high vortex density at large magnetic fields. Here, we report a giant reentrance of vortex pinning induced by increasing magnetic field in a W-based nanowire and a TiN-perforated film densely populated with vortices. We find an extended range of zero resistance with vortex motion arrested by self-induced collective traps. The latter emerge due to order parameter suppression by vortices confined in narrow constrictions by surface superconductivity. Our findings show that geometric restrictions can radically change magnetic properties of superconductors and reverse detrimental effects of magnetic field.

Nanowire (NW) detection is one of the fast and highly sensitive methods. An NW biosensor based on silicon-on-insulator (SOI) structures are used in the reported study for real-time label-free biospecific detection of the NFATc1 (D-NFATc1) cancer marker. For this purpose, the SOI NWs are functionalized with NFATc1 aptamers used as macromolecular probes. It is demonstrated that such a biosensor can ensure a detection limits up to 10−15 M, which is comparable with the sensitivity ensured by an NW biosensor with immobilized antibodies used as macromolecular probes. The results of this study demonstrate that such approaches to the development of sensor elements for highly sensitive diagnostics of diseases are really promising.

It is brought an approach of creation and close-packing two-dimensional photonic crystals with given sizes of elements by the EBL. The main problems of formation these structures were considered.

We present the results of the comparative study of the influence of disorder on transport properties in continuous and nanoperforated TiN films. We show that nanopatterning turns a thin TiN film into an array of superconducting weak links and stimulates both, the disorder- and magnetic field-driven superconductor-to-insulator transitions, pushing them to lower degree of disorder. We find that nanopatterning enhances the role of the two-dimensional Coulomb interaction in the system transforming the originally insulating film into a more pronounced insulator. We observe magnetoresistance oscillations reflecting collective behaviour of the multiconnected nanopatterned superconducting film in the wide range of temperatures and uncover the physical mechanism of these oscillations as phase slips in superconducting weak link network.

We present an experimental study of transport properties of a large two-dimensional array of superconductor-normal-metal-superconductor (SNS) junctions comprised of the nanopatterned superconducting film, ensuring that NS interfaces of our SNS junctions are highly transparent. We find the anomalously high charge transmission at certain applied voltages commensurate with the magnitude of the gap in superconducting islands. This indicates the nonlocal nature of the charge transfer in multiply connected SNS systems. We propose the mechanism of the correlated transmission of Cooper pairs in large arrays of SNS junctions based on the combined action of the proximity effect and the simultaneous Andreev conversion processes at many NS-interfaces. (C) 2009 Elsevier B.V. All rights reserved.

The properties of silicon-on-insulator nanowires (SOI NWs) fabricated by means of electron lithography and gas etching of SOI in XeF2 or SF6:CFCl3 have been investigated. The method used to fabricate the nanowires was found to require no additional anneal to be given to the final structure for defect removal after nanostructuring. The sensitivity of SOI NWs to negative protein BSA molecules in the pH 7.4 buffer solution was shown to be as high as 1 femtomoles. The gate characteristics of SOI NWs were used to determine the charge density of particles adsorbed on the NW surface. A charge density of 4.6 x 10(11) cm(-2) was estimated for a 1 femtomole protein concentration. The combined use of open-channel structures with top gates was employed for determining the charge state of structure surfaces after different chemical treatments. Chemical treatments giving rise to a density of the negative charges on the surface of NWs ranging in the interval (7-23) x 10(11) cm(-2) were examined. Treatments in methanol (after removal of the native oxide) were found to provide stabilization of the SOI surface over a 3-h interval after the treatments.