Top PDF Nonlinear Electrical Properties of One-Dimensional Nanostructures

Nonlinear Electrical Properties of One-Dimensional Nanostructures

Nonlinear Electrical Properties of One-Dimensional Nanostructures

2.5 Conclusion In this chapter, we have reported [1] on the fabrication and properties of superconducting nanowire arrays with good control over both cross section and length. The nanowires are compatible with device processing, allowing for the establishment of 4-point electrical contacts. We investigated Nb nanowires with individual nanowire cross sectional areas that range from bulk-like to 10 × 11 nm, and with lengths from 1 to 100 micrometers. Electrical measurements in the low-current and high-current limits indicate the nanowires obtained are uniform and effectively defect-free. Size effects on superconductivity are systematically studied; in particular, the ability to fabricate very long nanowires with identical cross sections allows for the first systematic investigation of length’s sole influence on superconductivity in nanowires, from which characteristic quasiparticle diffusion lengths are extracted. All results are interpreted within the context of phase-slip models.
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Statistical properties of nonlinear one-dimensional wave fields

Statistical properties of nonlinear one-dimensional wave fields

Statistical properties of nonlinear wave fields are investigated on a basis of direct hydrodynamical modeling of 1-D poten- tial periodic surface waves. The method is based on a non- stationary conformal surface-following coordinate transfor- mation; this approach reduces the principal equations of po- tential waves to two simple evolutionary equations for the el- evation and the velocity potential on the surface. The numer- ical scheme is based on a Fourier transform method. High accuracy was confirmed by validation of the nonstationary model against known solutions, and by comparison between the results obtained with different resolutions in the horizon- tal. The scheme allows reproduction of the propagation of steep Stokes waves for thousands of periods with very high accuracy. The method here developed is applied to simu- lation of the evolution of wave fields with large number of modes for many periods of dominant waves. The statistical characteristics of nonlinear wave fields for waves of different steepness were investigated: spectra, curtosis and skewness, dispersion relation, life time. The prime result is that wave field may be presented as a superposition of linear waves is valid only for small amplitudes. It is shown as well, that non- linear wave fields are rather a superposition of Stokes waves not linear waves.
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Mechanical properties of one-dimensional nanostructures, experimental measurement and numerical simulation

Mechanical properties of one-dimensional nanostructures, experimental measurement and numerical simulation

strain of a nanostructure measuring. Detailed lists of common procedures for different tensile tests are shown in Table 1.1. The highlighted methods are preferred when compared to other available methods. For sample picking-up and aligning, an ultra sharp probe is preferred to picking up nanostructures. Self-assembly is a better option for nanostructure alignment on a test apparatus. For force applying and measuring, a separate sensor measuring load applied on nanostructure has an advantage over cases where the cantilever serves as both sensor and actuator at same time, where displacement of a cantilever and a nanostructure are coupled with each other and special attention is needed for decoupling those two terms. Force measurement at micro and nano range remains challenging. Furthermore, the strain of a nanostructure is better calculated from a gauge length change, instead of a ―Cross-head‖ deformation which measures the average deformation along nanostructure length. As to the tensile test used in reference (Han, et al., 2007), the amount of load applied on nanostructures needs further investigation.
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Noise and electrical properties of YBCO nanostructures

Noise and electrical properties of YBCO nanostructures

CHAPTER 7 Noise and anticorrelation In this chapter we want to further investigate if the two level fluctuators, identified in resistance noise measurements performed on YBCO nanowires, can be related to fluctuations of some sort of local charge ordering. In the following, we first describe an experimental setup implementing cross-correlation noise measurements designed for the detection of fluctuating nematic order, which breaks rotational symmetry. The setup is inspired by a theoretical study of the local electronic order in the form of nematic patches in HTSs, which maps to the random field Ising model [149], e.g. a random resistor network, as shown in Fig. 7.1. Here the nematic order results in an in-plane anisotropy of the resistivity, i.e the resistivity has to be represented as a tensor [7]. We then introduce noise simulations to investigate what sort of signatures one can expect in cross correlated noise spectra. Here, we will assume that the total resistance noise is generated by nematic fluctuators and generic "isotropic" 1/f noise sources. In the final part of this chapter we present cross-correlation noise measurements performed on various YBCO nanowires having different lateral dimensions, and doping values.
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Fe-catalyzed growth of one-dimensional α-Si3N4 nanostructures and their cathodoluminescence properties

Fe-catalyzed growth of one-dimensional α-Si3N4 nanostructures and their cathodoluminescence properties

Although the exact bonding strength data are unknown, the bonding between Fe and graphitic carbon felt should be strong, considering the good wettability between liquid Fe and graphite (the contact angle #64u) 45,46 . The much higher growth rate along the growth direction than that along the width/thickness direction resulted in the formation of triangle morphology at the tip of nanobelt (Fig. 2b&d, Fig. 6f). Such a triangle tip could easily puncture the Fe-Si-N liquid droplet and continue to grow in the initial stage (Fig. 7Ic), leaving the liquid droplet at the roots due to the high pressure (P 5 F/S). However, the a-Si 3 N 4 nanowires had the same growth rate in the radial direction and thus formed a circular plane at their tops, which could push up the liquid droplet from the carbon felt because of the relatively low pressure. The above results and analysis indicated that the use of catalyst Fe should be a necessary but not sufficient condition for the formation of a-Si 3 N 4 nanobelts. It would interact with Si and N to form a Fe-Si-N liquid phase which favoured the anisotropic growth of a-Si 3 N 4 in the initial stage. Thus, it was more benefit for the formation of a-Si 3 N 4 nanobelts than for nanowires viewed from their contents in the products. This work further explained the formation mechanism of the long single crystal a-Si 3 N 4 nanobelts and also verified the rationality of the proposed combined catalytic VLS base-growth and VS tip-growth mechanisms although the nanobelt products had a few nanowires and branched nanostructures. Our work also demonstrates the reliability of the technical approach for the synthesis of a-Si 3 N 4 nanobelts. This strat- egy could perhaps be further extended to belt-like growth of III-N semiconductor materials.
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Protecting Surfaces Using One-Dimensional Nanostructures

Protecting Surfaces Using One-Dimensional Nanostructures

By adding carbon nano tubes to polymers, many of its properties were modified. So today they are one of the best fillers to polymeric composites [8]. In addition, by using a very small percentage of the CNT, other unique properties such as antifire, Lotus effect, anti-static, anti scratches enhanced mechanical properties [9]. In fact, by treating the surfaces with CNTs, multi-functional surfaces can be achieved.

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Morphological evolution, growth mechanism, and magneto transport properties of silver telluride one dimensional nanostructures

Morphological evolution, growth mechanism, and magneto transport properties of silver telluride one dimensional nanostructures

TeO 2‐ 3 þ N 2 H 4 → Te þ N 2 þ H 2 O ð 1 Þ Te þ N 2 H 4 þOH ‐1 →Te 2‐ þN 2 þH 2 O ð2Þ 2Ag þ þ Te 2‐ ¼ Ag 2 Te ð 3 Þ To investigate the magneto-transport properties of Ag 2 Te NWs, PPMS measurements were carried out. I-V characteristics of the nanowires at room temperature as a function of magnetic field (B = 1, 3, 5, and 7 T) are shown in Figure 5a. The black curve is the I-V of the magnetic field of 1 T. Obviously, the current increases nonlinearly with the increasing voltage. Without chan- ging the other experimental conditions, only changing B to 3 T, the I-V of the Ag 2 Te sample (red line) displays a smaller absolute value of the corresponding current and a larger resistance at the same voltage conditions. When the magnetic field is adjusted to 5 and 7 T (the blue and the green line), respectively, the absolute value of the current continues to decrease at the same voltage condi- tions. It is noteworthy that from Figure 5a, we can clearly see that ΔI from 1 to 3 T is larger than that from 3 to 7 T where the voltage is −4 V. That is to say, the I-V of Ag 2 Te sample is more sensitive at low magnetic field.
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One Dimensional Perovskite Manganite Oxide Nanostructures: Recent Developments in Synthesis, Characterization, Transport Properties, and Applications

One Dimensional Perovskite Manganite Oxide Nanostructures: Recent Developments in Synthesis, Characterization, Transport Properties, and Applications

characterize one-dimensional perovskite manganite nanostructures in the forms of nanorods, nanowires, nanotubes, and nanobelts. Various physical and chemical deposition techniques and growth mechanisms are explored and developed to control the morphology, identical shape, uniform size, crystalline structure, defects, and homogenous stoichiometry of the one-dimensional perovskite manganite nanostructures. This article provides a comprehensive review of the state-of-the-art research activities that focus on the rational synthesis, structural characterization, fundamental properties, and unique applications of one-dimensional perovskite manganite nanostructures in nanotechnology. It begins with the rational synthesis of one-dimensional perovskite manganite nanostructures and then summarizes their structural characterizations. Fundamental physical properties of one-dimensional perovskite manganite nanostructures are also highlighted, and a range of unique applications in information storages, field-effect transistors, and spintronic devices are discussed. Finally, we conclude this review with some perspectives/outlook and future researches in these fields.
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One Dimensional Nanostructures and Devices of II–V Group Semiconductors

One Dimensional Nanostructures and Devices of II–V Group Semiconductors

Although comprehensive efforts have been made toward the synthesis of high-quality 1-D II–V semiconducting nanostructures, there is still plenty of room left unex- ploited. We believe that future work should continue to focus on generating them in more controlled, predictable, and simple ways. The II–V semiconductors exhibit pro- nounced size quantization effects due to the large excitonic radii, thus, it is important to synthesize 1-D II–V semi- conducting nanostructures with diameters smaller than the excitonic radii. For example, one needs to find ways to get II–V semiconducting nanotubes with either very small diameter or very thin wall thickness. The physical and chemical properties of II–V semiconducting nanostructures with diameters smaller than the excitonic radii will then need to be investigated and more interesting results are expected to be gotten soon.
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Facile Synthesis and Tensile Behavior of TiO2 One Dimensional Nanostructures

Facile Synthesis and Tensile Behavior of TiO2 One Dimensional Nanostructures

gel process and anodic oxidation require further heat treatment to improve the crystallinity of as-synthesized nanostructures, which adds to the complexity of the pro- cesses. A few ‘‘dry’’ synthetic methods including vapor transport, metal–organic chemical vapor deposition (MOCVD), and annealing have been reported. The vapor transport method involves thermal evaporation of titanium (Ti) sources (e.g., Ti or TiO powders), transport of Ti-containing vapors, and final growth of TiO 2 nanostruc- tures on Ti-coated substrates [4–6]. This method requires precise control of source temperatures and reaction tem- peratures, which can be experimentally challenging. The MOCVD method can grow well-aligned TiO 2 1D nano- structures [7, 8]. However, the MOCVD system setup is complicated and expensive. The annealing method grows TiO 2 1D nanostructures by direct oxidation of Ti foils using acetone, ethanol, or dibutyltin dilaurate (DBTDL) vapor as oxygen (O 2 ) sources [9–11]. While this method is relatively simple, the use of organic vapor could introduce carbon contamination and result in the growth of TiO 2 core- amorphous carbon shell structures [10]. Thus, it is necessary to seek simpler and more reliable ‘‘dry’’ synthetic methods to synthesize high quality TiO 2 1D nanostructures. In addition, since mechanical stability is a crucial factor for structural integrity for the intended applications of TiO 2 nanostructures, it is important to study the mechanical properties of individual TiO 2 1D nanostructures.
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One dimensional silver nanostructures on single wall carbon nanotubes

One dimensional silver nanostructures on single wall carbon nanotubes

This view is consistent with recent experimental work. Sakashita reported the enhancement of photolumines- cence intensity of single carbon nanotubes coupled to a rough gold surface. It was attributed to local field enhancement of the incident light induced by localized surface plasmons [24]. However, the effect of plasmonic nanoparticles on the optical properties on SWCNT results in localized absorption in the neighborhood of the nanoparticle absorption plasmon wavelength, as opposed to the rather broad absorption spectra resulting from the excitation of the longitudinal plasmon mode observed here. In the case of silver nanospheres, the transverse mode is located between 300 and 400 nm.
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Fabrication routes for one-dimensional nanostructures via block copolymers

Fabrication routes for one-dimensional nanostructures via block copolymers

Abstract Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostruc- tures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers with unique properties and come in many types and shapes. Their properties are highly dependent on the blocks of the copolymers, thus allowing easy tunability of its properties. This review briefly focusses on the use of block copolymers for synthesizing one-dimensional nanostruc- tures especially nanowires, nanorods, nanoribbons and nanofibers. Template based, lithographic, and solution based approaches are common approaches in the synthesis of nanowires, nanorods, nanoribbons, and nanofibers. Synthesis of metal, metal oxides, metal oxalates, polymer, and graphene one dimensional nanostructures using block copoly- mers have been discussed as well.
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Thermophotovoltaic Emitters Based on a One Dimensional Metallic Dielectric Multilayer Nanostructures

Thermophotovoltaic Emitters Based on a One Dimensional Metallic Dielectric Multilayer Nanostructures

can be achieved. In this paper, a 1D 5-layer microstructure made of tungsten and silicon dioxide SiO 2 in the form of (W/SiO 2 / W/SiO 2 /W) is proposed and fabricated to use as a wavelength-selective and polarization-insensitive TPV emitter. The radiative properties were calculated and measured by the rigorous coupled-wave analysis RCWA and the spectral transmittance and reflectance measurement system. The bidirectional distribution function BRDF was also measured by using three axis automated scatterometer system TAAS at room temperature. The effects of the diffraction order and plane of incidence on the spectral emittance were investigated numerically.
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One-Dimensional Oxide Nanostructures as Gas-Sensing Materials: Review and Issues

One-Dimensional Oxide Nanostructures as Gas-Sensing Materials: Review and Issues

Abstract: In this article, we review gas sensor application of one-dimensional (1D) metal- oxide nanostructures with major emphases on the types of device structure and issues for realizing practical sensors. One of the most important steps in fabricating 1D-nanostructure devices is manipulation and making electrical contacts of the nanostructures. Gas sensors based on individual 1D nanostructure, which were usually fabricated using electron-beam lithography, have been a platform technology for fundamental research. Recently, gas sensors with practical applicability were proposed, which were fabricated with an array of 1D nanostructures using scalable micro-fabrication tools. In the second part of the paper, some critical issues are pointed out including long-term stability, gas selectivity, and room- temperature operation of 1D-nanostructure-based metal-oxide gas sensors.
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Electrical and Photoelectrical Properties of Reduced Graphene Oxide—Porous Silicon Nanostructures

Electrical and Photoelectrical Properties of Reduced Graphene Oxide—Porous Silicon Nanostructures

Analyzing the obtained dependencies, one can conclude that hybrid PS–RGO structures have slightly smaller photoresponse times to green light as compared to IR ra- diation. The observed temporal parameters of the photo- response to light pulses of different wavelengths can serve as an additional argument in favor of our hypothesis that various layers of the hybrid structure are responsible for the absorption of light quanta of different energy.

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The Structural and Electrical Properties of Nanostructures ZnO Thin Films on Flexible Substrate

The Structural and Electrical Properties of Nanostructures ZnO Thin Films on Flexible Substrate

Research on a flexible substrate has been attracting much attention nowadays due to its attractive properties such as light weight and high resistance to impact damage. These properties make them suited for the fabrication of electronic device. Due to the poor thermal endurance of flexible substrate, zinc oxide (ZnO) is one of the materials that can be grown at lower deposition temperatures [1]. ZnO is naturally n-type direct band gap semiconductor materials that possess some great characteristics which are wide energy band gap, 3.37eV at room temperature and large free exciton binding energy, 60meV. It has the hexagonal crystalline structure of the wurtzite type and unit cell with a constant a = 3.24 Å and c = 5.19 Å as shown in Fig. 1.
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Thermal and Electrical Transport Study of One Dimensional Nanomaterials

Thermal and Electrical Transport Study of One Dimensional Nanomaterials

11 increased from 1.5 to 24.6 at %. It is believed the highest conductivity (lowest resistivity) of AZO occurs when the Al concentration is in the range of 1~3 at%. With a large Seebeck coefficient, the thermoelectric efficiency of ZnO is limited by its high thermal conductivity (~40 W/m.K). Recently Al doped ZnO nanocomposites 33 have shown an enhanced thermoelectric figure of merit ZT ≈ 0.44 at 1000 K as a result of up to a factor of 20 lower thermal conductivity deduction from non-nanostructured ZnO, while retaining bulk like thermopower and electrical conductivity. Hence an even further reduction in thermal conductivity and thus a higher thermoelectric efficiency, due to stronger phonon scattering from size effect and dopant impurities can be expected, when one-dimensional nanostructures are employed with dopants.
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Fabrication of one-dimensional organic nanostructures using anodic aluminum oxide templates

Fabrication of one-dimensional organic nanostructures using anodic aluminum oxide templates

Organic nanostructures are new comers to the fields of nanoscience and nanotechnology. In recent years novel methods for controlling the growth and uniformity of one-dimensional (1D) organic nanostructures (nanowires and nanotubes) have been developing. The use of hard templates as molds for the formation of organic nanowires or nanotubes seems to be a reliable and convenient method. In this review we will discuss the use of anodic aluminum oxide (AAO) templates as the inorganic hard template of choice. We will briefly survey advances in the fabrication of 1D polymer nanostructures using AAO templates, while the bulk of the review will focus on the synthesis of small molecule nanowires, nanotubes, and nanorods. We will also discuss unique properties of some highly crystalline small molecule nanorods fabricated using AAO templates.
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Numerical Simulation of Synthesis of One-Dimensional Molybdenum Oxide Nanostructures in Flame Environment.

Numerical Simulation of Synthesis of One-Dimensional Molybdenum Oxide Nanostructures in Flame Environment.

2 is rather high and ensures that many constituent atoms are exposed on their surface. A keen interest in the production of nanoparticles was spurred by their display of some highly desirable traits such as increased catalytic activity (Beck, et al., 1992), superplasticity (Karch, et al., 1987) and higher theoretical densities. The products manufactured with some nanomaterials show higher toughness (Karch, et al., 1990) and ductility. One-dimensional nanostructures are commonly defined as nanoparticles with an aspect ratio greater than or equal to 3. One-dimensional nanostructures include a wide variety of products like whiskers, fibers, nanowires and nanorods. Although whiskers and nanorods are generally considered shorter than nanowires and fibers. 1-D nanostructures, as generally accepted, provide a sound basis to investigate the dependence of electrical and thermal transport on the dimensionality of nanostructures.
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Electrical control of spin dynamics in finite one dimensional systems

Electrical control of spin dynamics in finite one dimensional systems

DOI: 10.1103/PhysRevB.84.155436 PACS number(s): 75.78.−n, 75.30.Hx, 73.63.−b, 85.75.−d I. INTRODUCTION The rapid development of the field of spintronics 1 over the past two decades has uncovered exciting and novel phenomena related to the dynamics of the electronic spin in a wide variety of systems, ranging from bulk materials to spatially confined structures. 2 Fueled by the ever-growing needs for speed, capacity, and energy efficiency in computing, the central objective in understanding and ultimately controlling the spin properties in the solid state has been constantly shifting toward the nanoscale. At these lengths and times the conventional methods for spin control, based on magnetic fields alone, are limited by scalability issues. Alternative approaches are thus sought and they typically involve electric fields of some form. 3 One way to manipulate spins by purely electrical means relies on the spin-transfer torque mechanism. 4 This approach uses spin-polarized currents to control the direction of the magnetization and has been realized in various nanostruc- tured materials ranging from magnetic multilayers 5 to, more recently, single atoms in STM-type geometries. 6 Alternative to electric current control is the optical control, such as in the laser-driven ultrafast magnetization switching. 7,8 In a somewhat different context, the optical manipulation of single spins in bulk media 9 is at the heart of the most promising candidates for the quantum information processing technology. 10,11
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