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This paper describes analysis and simulations of Si and III-V Gate-All-Around nanowire MOSFETS assuming ballistic or quasi-ballistic transport. It is found that either channel material can provide the higher saturation current depending on the oxide thickness. For effective oxide thickness above approximately 0.5nm, the higher electron velocity of III-V's outweighs the higher density of states available in the Si device associated with higher effective mass and valley degeneracy and result in higher current for the III-V device. However, materials with higher effective mass and valley degeneracy result in smaller on-resistance in ballistic limit. Depending on the gate oxide capacitance, valley degeneracy may influence the attainable saturation current in a positive or negative way.

The Co-Ni alloy nanowires were electrodeposited into porous anodic aluminum oxide (AAO) templates. At the first, highly ordered AAO templates were synthesized by two-step anodizing of aluminum to increase pore ordering. Arrays of nanowires with diameter about 30 nm and length about 5000 nm were electrodeposited by alternating current. The composition and structure property of nanowires were investigated by EDX, SEM and TEM techniques. It was found that nanowire composition was related to ions concentration in solution and it was shown that at the optimum potential range of electrodeposition (17-19 V), a change at the potential was shown no strong effect on chemical composition of nanowires. It was observed that nano pores were filled continuously and so nanowires were dense with uniform composition in nanowire length.

La-doped and Cu-doped ZnO nanowires have been prepared to compare the substitution effect on the microstructural and magnetic properties. The XRD patterns of both compositions with single diffraction peak (002) show the same wurtzite hexagonal structure. The growth rate of the ZnO nanowires were enhanced by Cu doping, which were different from the suppression of growth rate by La doping. Room temperature ferromagnetism is observed for all ZnO, Cu-doped ZnO and La-doped ZnO nanowires. The saturation magnetizations are 0.102, 0.232 and 0.04 emu/g for ZnO, Cu-doped ZnO and La-doped ZnO nanowires, respectively. The results showed that the ferromagnetism is restrained by Cu doping, but enhanced by the La doping.

The quantum vacuum fluctuation i.e., Casimir attraction can induce mechanical instability in ultra-small devices. Previous researchers have focused on investigating the instability in structures with planar or rectangular cross-section. However, to the best knowledge of the authors, no attention has been paid for modeling this phenomenon in the structures made of nanowires with cylindrical geometry. In this regard, present work is dedicated to simulate the Casimir force-induced instability of freestanding nanoactuator and nanotweezers made of conductive nanowires with circular cross-section. To compute the quantum vacuum fluctuations, two approaches i.e., the proximity force approximation (for small separations) and scattering theory approximation (for large separations), are considered. The Euler-beam model is employed, in conjunction with the size-dependent modified couple stress continuum theory, to derive governing equations of the nanostructures. The governing nonlinear equations are solved via three different approaches, i.e., using lumped parameter model, modified variation iteration method (MVIM) and numerical solution. The deflection of the nanowire from zero to the final stable position is simulated as the Casimir force is increased from zero to its critical value. The detachment length and minimum gap, which prevent the instability, are computed for both nanosystems.

In this paper, the effect of incident light intensity, relaxation time, core radius and shell thickness on linear, nonlinear, total optical absorption coefficients and refractive index changes in $GaN/A{l}_{0.1}G{a}_{0.9}N$ core–shell nanowire are theoretically investigated. The presented nanostructure is a cylindrical quantum wire including a shell around the cylinder core. By numerical solution of Schrödinger equation in the cylindrical coordinates with effective mass approximation, the optical absorption coefficients are calculated. The results show that the magnitude of optical absorption coefficients can be adjusted by varying the relaxation time. The positions of resonant peaks of optical absorption coefficients are redshifted by increase of core radius due to decrease of the energy difference between two energy levels. With increase of shell thickness initially, the resonance wavelength of absorption coefficient increases (redshift) and magnitude of absorption coefficient decreases. Then with more increases of the shell thickness, redshifting of resonance wavelength is stopped and magnitude of absorption coefficient is increased. There is a significant increase in the refractive index change with increase of relaxation time.

The ferrimagnetic mixed spin-1/2 and spin-1 cubic Ising nanowire is studied in the framework of the Monte Carlo simulation. The competition between the bilinear interaction and crystal field of spin-1 atoms as well as the nanowire size effect is highlighted. The corresponding phase diagram is discussed showing compensation points and critical second-order phase transitions. The effect of an external magnetic field and the hysteresis loops behavior are also carried out. Finally, we compare our results with other works in the literature.

The energy relaxation of hot electrons is proposed based on the spin–orbit (SO) interaction of both Rashba and Dresselhaus types with the effect of hot phonons. A continuum theory of optical phonons in nanowires taking into account the influence of confinement is used to study the hot-electron energy relaxation. The energy relaxation due to both confined (CO) and interface (IO) optical phonon emission on nanowire radius, electrical field strength, parameters of SO couplings and electron temperature is calculated. For considered values of the nanowire radius as well as other system parameters, scattering by IO phonons prevails over scattering by CO phonons. The presence of an electric field leads to the decrease of power loss in transitions between states with the same spin quantum numbers. With the increase of the electric field strength, the influence of the Dresselhaus SO interaction on the energy relaxation rate decreases. The effect of SO interaction does not change the previously obtained increasing dependence of power loss on electron temperature. The sensitivity of energy relaxation to the electric field also through the Rashba parameter allows controlling the rate of energy by electric field.

The triangular-type Ising nanowire is constructed on the Bethe lattice (BL) by using the core-shell structure consisting of spin-3/2 atoms as the core and spin-1/2 atoms as the triangular shell. Each triangular plaquette of spins forms a nanoparticle which is connected to upper and lower plaquettes symmetrically. The additions of the plaquettes continue indefinitely until the thermodynamic limit to construct the nanowire. The inter- and intra-bilinear interaction parameters (J) are assumed to be positive or negative to simulate the ferromagnetic (FM) or antiferromagnetic (AFM) interactions, respectively. The crystal field for spin-3/2 and external magnetic field for all sites are also included into the model. After obtaining the formulation of the model in terms of exact recursion relations (ERRs), the thermal variations of magnetizations are studied in detail to obtain the phase diagrams. It is found that the model leads to different types of FM and AFM regions with various forms of phase transitions. It is also interesting that the model presents random or oscillatory magnetization behavior regions for the appropriate values of our system parameters.

Scanning near-field optical microscope (SNOM) was employed to investigate the room temperature photoluminescence (PL) of single ZnO nanowires with different radii excited by 325 nm laser. Two-dimensional distribution of their PL intensity is provided for the analysis of intensity decay from emission source. It is found that the PL intensity at both ends of each ZnO nanowire (end emission) was much stronger than that at the sides of the wire (side emission). Further investigation indicates that the quality of end emission depends on the diameters of the wires. Some of the ZnO nanowires with special diameters emit stronger light, and the shape of the light is close to Gauss beam. In addition, the Gauss shape light can diffuse longer distance than what the side emission does, typically in the range of a few micrometers. It is a sign of the fact that special guided modes of the PL light are formed in the nanowires. The calculation results predicate that the special guiding mode strongly relies on the diameters of the ZnO nanowires. The good directional property and high intensity of the end emission have many potential applications, including optical switch and microanalysis. It has been shown that SNOM can provide direct evidence of light emission properties from single nanowires, and hence provide the clue of increasing light efficiency and the improvement of light-propagating mode.

Uniform and aligned ZnO nanotube arrays have been synthesized by annealing Zn nanowire arrays in anodic aluminum oxide (AAO) membrane. In our method, Zn nanowire arrays were fabricated by electrochemical deposition technique based on ordered nanoporous AAO, and then a heat-treatment method was used to convert Zn nanowire arrays to ZnO nanotube arrays. The ZnO arrays were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and absorption spectra. The results show that the polycrystalline ZnO nanotubes have a diameter of about 45 nm. This method can also be used to fabricate other metal oxide nanotube arrays.

In this paper, we investigate low-temperature thermal conductance in three-dimensional nanowire embedded with phonon cavity based on the full scalar model of elasticity. The results show that at very low temperatures, the cavity can enhance the thermal conductance in certain lateral-width range, just as the constructive coupling of more phonon-modes excited in the cavity with modes in the transport region. At higher temperatures, however, the scattering of more interfaces formed from the cavity become a dominant factor to suppress the phonon transmission. Moreover, it is found that while the material in the cavity is substituted for the material with higher sound velocity than that in the transport region, the thermal conductance is also enhanced.

In this work, the strain dependence of electronic and optical properties in wurtzite zinc oxide (ZnO) lattice were explored. Ab initio density functional theory (DFT) was used in evaluating the energy bandgap and the dielectric tensor, respectively. The influence on the bandgap due to the shear distortion was so small that the reducing linear trends on uniaxial compressive/tensile strain were reported, in which the evolution of the absorption curve with uniaxial strain agrees well with the experimental results across the bending section. This study provides a set of useful data in analyzing the evolution of the optical adsorption across the bending ZnO nanowire, and gives a systematic explanation to the available experiments from the electronic structure’s perspective.

In the scaling down of electronic devices, functional oxides with strongly correlated electron system provide advantages to conventional semiconductors. We report the fabrication of the electric double layer transistor (EDLT) with the (La,Pr,Ca)MnO₃ (LPCMO) epitaxial nanowall wire (NW) channel whose width was less than 100 nm. The width controlled LPCMO NWs were fabricated using an original nanofabrication technique: 3D nanotemplate pulsed laser deposition. The LPCMO NW EDLT was produced by employing 80 nm width NWs as channel. The produced LPCMO NW EDLT showed low leakage current. The metal-insulator transition property was successfully modulated by gating effect on the LPCMO NW EDLT.

An optical AND logic device based on chiral surface plasmon polaritons (SPPs) is theoretically proposed. The AND logic device is made up of five Y-shape nanowires with two input ports and one output port. Chiral SPPs excited at the end of input ports propagate along the nanowire. By adding two gold blocks on one side of the AND logic device, the chirality of the device is amplified. By modifying parameters, we find suitable parameters to design the structure with a large chirality at the working wavelength. By setting the threshold, we achieve the AND logic devices. Our structure may provide a significant component in signal transmission and processing devices.

Gate-All-Around (GAA) MOSFETs have been investigated as promising new device structures, and Germanium is used for its high carrier mobility. In this paper, a 3D parallel Monte Carlo simulation of GAA Ge nanowire nMOSFET with effective potential method is implemented. Compared the simulation results with classical results, we can see that the quantum effects affect on the distribution of density, velocity and energy, and they make a decrease on the drain current as well.

Nanosystems have great potential in practical applications such as: sensors, circuits, solar panels, super strong materials, protective coatings, and drug delivery. Much research is devoted to designing and fabricating these nanosystems. However, the question of reliability is often overlooked during the design process. Specifically, the ability to analyze the reliability of the nanocomponents is lost. In this paper, we introduce the use of Approximate Bayesian Computation to assess nanocomponent reliability. Data on the lifetime of the nanocomponents is not required with this approach; instead data on the lifetime of the nanosystem is utilized. The proposed statistical and computational algorithms result in a more comprehensible understanding of the nanosystem in order to improve the overall reliability.

In this work, we report the morphology and optical properties of zinc oxide (ZnO) layers prepared by dry thermal oxidation at different annealing conditions. Morphology studies using scanning electron microscope (SEM) show that the amount of nanowires and nanosheets increases with the introduction of a flow of O₂ gas. High-resolution X-ray diffraction (HR-XRD) data show that typical polycrystalline ZnO nanostructure layers have been deposited. Near-perfect stoichiometry of Zn and O atom vacancies has been observed from energy dispersion spectroscopy (EDS) spectrum. Photoluminescence (PL) spectra show strong peaks at UV and green regions. An increase in the stoichiometry of ZnO has been achieved with the oxygen gas flow during annealing indicating that deep-level defects represented by interstitial oxygen and antisite oxygen are gas pressure dependent. A single exciton peak with binding energy 60 meV has been observed at room temperature.

Pre-annealing as part of a two-step thermal oxidation process has a significant effect on the growth of hematite ($\alpha$-Fe₂O₃) nanowires on Fe foil. High-density aligned nanowires were obtained on iron foils pre-annealed at 300${}^{\circ }$C under a dry air flow for 30min. The X-ray diffraction (XRD) patterns indicate that the nanowires are transformed from the small $\alpha$-Fe₂O₃ grains and uniquely grow in the (110) direction. The formation of a high-density of small grains by pre-annealing improved the alignment and density of the $\alpha$-Fe₂O₃ nanowires.

Quenching effect of photoconductive semiconductor material has important applications in areas like detecting semiconductor defect and infrared light. In this paper, vapor–liquid–solid (VLS) method is improved to grow nanowires by using a heat resisting quartz tube as the vessel. With the conditions of gold catalysis, appropriate temperature, and ease of handling, gradient-bandgap CdSSe nanowires were grown successfully. We study the quenching effect of different component parts of the nanowire, respectively, and find that the quenching degree increases with the increasing optical intensities of different bandgap nanowires when the power injection is below 10${}^{-8}$W. However, since more recombination centers would turn into the trap energy level centers leading to more electrons to jump into the conduction band with the increasing density of CdS, the peak of quenched rate for 90% CdS proportion nanowire arrives earlier than 90% CdSe proportion, and the peak of quenched rate for CdSe still does not appear even when the optical intensity reaches 10${}^{-6}$W. Our experiment provides an effective and convenient method for the defect-level detection of semiconductor materials, and can also develop high resolution infrared detectors under the material limitation conditions.

Nanotubes and nanowires of π-conjugated polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) were synthesized using Al₂O₃ nanoporous template through electrochemical polymerization method. From the SEM and TEM photographs, the formation of conducting polymer nanotube (CPNT) and nanowire (CPNW) was confirmed. From FT-IR and UV/Vis absorbance spectra, we observed the effect of doping and de-doping through HF or NaOH dissolving of Al₂O₃ template. DC conductivity and I–V characteristics as a function of temperature and gate bias were measured for the CPNTs and CPNWs prepared with various synthetic conditions. Magnetic properties were measured through EPR experiments. Based on the results, we compare the intrinsic properties between bulk and nanoscale π-conjugated polymers.