We investigate the radiation response of single-walled carbon nanotube (SWCNT) thin-film transistors fabricated with 23 nm silicon oxynitride gate dielectric layers, for total ionizing doses (TIDs) of Co-60 gamma irradiation up to 2 Mrad(Si). Irradiations with ±1 MV/cm across the gate dielectric have little effect on the threshold voltage, yielding shifts of less than ±0.25 V and no detrimental effect on SWCNT mobility or maximum drain current. This illustrates the need to consider the total device material composition when investigating the radiation response of carbon nanoelectronics and substantiates the applicability of SWCNT-based nanoelectronics for use in high TID environments.

We study the one-pot facile hydrothermal growth of ultralong silver–carbon (Ag–C) nanocables with Ag nanowires as the cores and carbon as the sheaths through the mediation of H2SO4 and without using an organic surfactant. In the investigation, Ag–C nanostructures were systematically and extensively examined as a function of both temperature and H2SO4 concentration to locate the optimal conditions for preparing ultralong, robust, and uniform Ag–C coaxial nanocables at T = 180 °C and 0.5 M H2SO4. The characterization clearly demonstrated a simple, efficient, and surfactant-free synthesis of Ag–C nanocables. In the hydrothermal process, glycerol acts as both reducing agent and carbon source, while H2SO4 mediates the directional growth of the silver nanowire core and assists the deposition of carbon. Moreover, the nanocables manifest unusual ferromagnetism at room temperature and a plausible mechanism of forming Ag–C nanocables was proposed as a result of the chain-like hydrogen sulfate compounds owing to the H2SO4 mediation.

Although highly magnetostrictive thin films of Terfenol-D have been produced by a variety of methods, high-quality thick films have proved to be far more challenging to produce. To date, thick film processes have resulted in nanoparticulate films that contain significant porosity that reduces stiffness and results in oxidation and poor magnetostrictive performance. With the goal of understanding microstructural and compositional factors that affect performance, nanoparticulate Terfenol-D thick films were produced by laser ablation of microparticle aerosols combined with supersonic impaction. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photon spectroscopy, and magnetic measurements were performed on nanoparticles and on films as-deposited and after annealing in vacuum or in a reducing atmosphere. These measurements show that segregation occurs during oxidation of the films, prior to annealing, and results in films with poor magnetostriction. The segregation persists during annealing with no visible changes to the morphology or density of the nanoparticulate films exposed to temperatures as high as 800 °C. These results suggest that oxidation and segregation must be avoided to produce highly magnetostrictive thick films.

Matusi–Akaogi force field is used in molecular dynamics simulations to generate three samples of amorphous TiO2 of 3-nm size under different heating and quenching rates. The averaged pair correlation functions, coordination numbers, bond lengths, bond angles, and dihedral angles are calculated at 315 K. It is found that overcoordinated Ti and O atoms are in the core region, 6- and 3-fold coordinated Ti and O atoms are in the central part, and undercoordinated Ti and O atoms are in the vicinity of the surface. The correlations are significant up to 10 Å and vanish at the particle size. The calculated averaged bond lengths for short-range interparticle correlations agree with the experimental data. The discrete bond angles and dihedral angles of crystalline sphere get distributed over complete range in the amorphous phase and closer strained atomic network is predicted. The relative variance in the atomic arrangements in three samples is within 4%.

In this work, we compare the synthesis of germanium nanowires (GeNWs) using a highly localized heat source with GeNWs synthesized in a uniform temperature environment. With the exception of thermal environment, identical synthesis parameters were maintained in all experiments. The localized heat source, a suspended silicon microscale heater, enabled site-specific synthesis and thus the direct integration of GeNWs which is presented for the first time. The effect of heat source implementation and local temperature gradients on the resulting nanowires is assessed in terms of resulting nanowire geometry, growth rate, and quality. Overall, we note a reduction in growth rate and elevated kinking levels in locally synthesized nanowires when compared to nanowires synthesized in uniform temperature processes. The taper which typically characterizes GeNWs, however, is significantly reduced. Finally, we explore branching behavior which hints of instabilities in the synthesis process as nanowires grow away from the heat source.

The unique and highly utilized properties of TiO2 nanotubes are a direct result of nanotube architecture. To create different engineered architectures, the effects of electrolyte solution, time, and temperature on the anodization of titanium foil were studied along with the resultant anodized titanium oxide (ATO) nanotube architectures encompassing nanotube length, pore diameter, wall thickness, smoothness, and ordered array structure. Titanium foil was anodized in three different electrolyte solutions: one aqueous [consisting of NH4F and (NH4)2SO4] and two nonaqueous (glycerol or ethylene glycol, both containing NH4F) at varying temperatures and anodization times. Variation in anodization applied voltage, initial current, and effect of F− ion concentration on ATO nanotube architecture was also studied. Anodization in the aqueous electrolyte produced short, rough nanotube arrays, whereas anodization in organic electrolytes produced long, smooth nanotube arrays greater than 10 μm in length. A position effect, relative to the solution–air interface, was observed in this work. Furthermore, it was found that anodization in glycerol at elevated temperatures for several hours could possibly produce freely dispersed individual nanotubes.

An array of 32 sensor elements with single-walled carbon nanotubes (SWCNTs) as the sensing medium has been fabricated. The microfabrication approach used allows reduction of the chip size and increases the number of sensor elements in a chip and is amenable for large wafer scale-up. The sensor array chip is designed as an electronic nose for use with the aid of a pattern recognition algorithm. The sensor chips were tested for NO2 sensing and interfering effects from humidity and a background of chlorine. The results indicate that NO2 can be detected at low concentration levels of 0.5 ppm in the presence of chlorine at 30 times higher concentrations. The sensor response is affected by humidity, which implies that the training data set for NO2 detection needs to be generated for multiple humidity levels for interpolation purposes during field use.

In this article, scanning nonlinear dielectric microscopy (SNDM) with atomicresolution is reviewed. First, experimental results on the detection offerroelectric domains are shown following a presentation about the theory andprinciple of SNDM. Next, a three-dimensional (3D) type of SNDM for measuring the3D distribution of ferroelectric polarization and noncontact scanning nonlineardielectric microscopy (NC-SNDM) are proposed. Using NC-SNDM under ultrahighvacuum conditions, we clearly resolve the electric dipole moment distribution ofSi atoms on a Si(111)7 × 7 surface. We also succeeded to resolve afullerene (C60) molecule. Since the technique is applicable not onlyto semiconductors but also to both polar and non-polar dielectric materials,SrTiO3 and TiO2 surfaces were observed by NC-SNDM.Finally, we characterize an ultrahigh-density ferroelectric data storage systemusing SNDM as a pickup device and a congruent lithium tantalate single crystalas a ferroelectric recording medium.

Carbon nanocoils (CNCs) with diameter from 100 to 150 nm have been synthesized by catalytic decomposition of acetylene at 700 °C using Fe–Sn–O catalyst film prepared by a spin-coating method. The CNCs are much smaller in diameter than those synthesized using the catalysts prepared by a sol-gel method and a solution-dipping method. It is found that catalyst films with different morphologies are obtained by changing the spin-coating times, which lead to the formation of different multilayer carbon nanostructures, including CNCs/carbon layer/vertically aligned carbon nanotubes sandwich-like structures, and CNCs/carbon double-layer structures. Based on the experimental results, the growth mechanism of the multilayer carbon nanostructures has been proposed.

A cornerstone in the successful application of semiconductor nanowire devices is controlled impurity doping. In this review article, we discuss the key results in the field of semiconductor nanowire doping. Considerable development has recently taken place in this field, and half of the references in this review are less than 3 years old. We present a simple model for dopant incorporation during in situ doping of particle-assisted growth of nanowires. The effects of doping on nanowire growth are thoroughly discussed since many investigators have seen much stronger and more complex effects than those observed in thin-film growth. We also give an overview of methods of characterizing doping in nanowires since these in many ways define the boundaries of our current understanding.

Co3O4-based spinels are a new class of wide-band-gap p-type conductive oxides with high work functions. We examined the structures, conductivities, work functions, and optical spectra of quaternary Zn–Ni–Co–O thin films across the entire spinel region of the ZnO–NiO–Co3O4 diagram using a high-throughput combinatorial approach. We found that the conductivity of as-deposited films is maximized (100 S/cm) and optical absorption (at 1.8 eV) is minimized in different regions of the diagram, while the work function of annealed films is high and relatively constant (5.8 ± 0.1 eV). These properties made Zn–Ni–Co–O thin films applicable as p-type interlayers in solar cells. As an example, amorphous Zn–Co–O hole transport layers had good performance in bulk heterojunction organic photovoltaic devices.

The failure mechanism of lead-free solder interconnections of chip scale package–sized Ball Grid Array (BGA) component boards under thermal cycling was studied by employing cross-polarized light microscopy, scanning electronic microscopy, electron backscatter diffraction, and nanoindentation. It was determined that the critical solder interconnections were located underneath the chip corners, instead of the corner most interconnections of the package, and the highest strains and stresses were concentrated at the outer neck regions on the component side of the interconnections. Observations of the failure modes were in good agreement with the finite element results. The failure of the interconnections was associated with changes of microstructures by recrystallization in the strain concentration regions of the solder interconnections. Coarsening of intermetallic particles and the disappearance of the boundaries between the primary Sn cells were observed in both cases. The nanoindentation results showed lower hardness of the recrystallized grains compared with the non-recrystallized regions of the same interconnection. The results show that failure modes are dependent on the localized microstructural changes in the strain concentration regions of the interconnections and the crack paths follow the networks of grain boundaries produced by recrystallization.

Semiconductor nanowires (NWs) are characterized by an extraordinarily large surface-to-volume ratio. Consequently, surface effects are expected to play a much larger role than in thin films. Here, we review a research focused on the impact of the surface on the electrical and optical properties of catalyst-free GaN NWs with growth direction <0001>. Using a combination of complementary experimental techniques, it has been shown that the Fermi level is pinned at the NW sidewall surfaces, resulting in internal electric fields and in full depletion for NWs below a critical diameter. Deoxidation of the surfaces unpins the Fermi level, leading to enhanced radiative recombination of excitons. Prominent absorption below the bandgap is caused by the Franz-Keldysh effect. Close to the surface, the ionization energy of donors is reduced. The consideration of surface-induced effects is mandatory for an understanding of the physical properties of NWs as well as their application in devices.

Recent extensive nanomechanical experiments have revealed that the instantaneous strength and plasticity of a material can be significantly affected by the size (of sample, microstructure, or stressed zone). One more important property to be added into the list of size-dependent properties is time-dependent plastic deformation referred to as creep; it has been reported that the creep becomes more active at the small scale. Analyzing the creep in the small scale can be valuable not only for solving scientific curiosity but also for obtaining practical engineering information about the lifetime or durability of advanced small-scale structures. For the purpose, nanoindentation creep experiments have been widely performed by far. Here we critically review the existing nanoindentation creep methods and the related issues and finally suggest possible novel ways to better estimate the small-scale creep properties.

We report here a finite element simulation of the compression of inorganic WS2 hollow nanoparticles. The particle was modeled as a multilayered polyhedron to investigate the effect of the unique onion-like and highly faceted structure in the mechanical response. The simulation revealed the central role of the faceted structure of the WS2 nanoparticles in the mode of failure. The stress magnitude and distribution was shown to be size dependent, as predicted from previously published experimental results. Moreover, the simulation points to the influence of the layered structure on the energy release during compression loading via interlayer shear.

The effects of water vapor and oxygen on the cyclic fatigue behavior of oxygen-excess La0.8Sr0.2MnO3+δ (LSM) were investigated under three-point bending at 1273 K. Because the fatigue life did not obviously depend on the number of cycles, which also represented the effective time of the applied stress, the fracture was presumed to not be significantly controlled by stress-corrosion cracking. Under a low oxygen partial pressure (), however, wet exposure inhibited both fatigue fracture and permanent deformation, in which the LSM crystal lattice was distorted and the unit cell free volume was reduced. Under a high , on the contrary, the crystal symmetry was increased by the wet exposure. The inhibition of fatigue fracture and deformation at both high and low was probably caused by retardation of lanthanum diffusion through its vacancies.

A method of fabricating oriented single-crystalline SrRuO3 nanowire arrays using a bottom-up approach relying on diffusion-controlled self-organization is demonstrated. DyScO3 substrates exhibiting an ordered striped phase of DyO and ScO2 chemical termination are used as a template for pulsed laser deposition growth of SrRuO3. Here SrRuO3 preferentially nucleates on one type of termination. The resulting nanowires are single crystalline, conducting and isolated from each other, typically 100 nm wide and 5–10 nm high. This preferential growth is studied using a kinetic Monte Carlo model, which provides a guide to optimize growth conditions and tune the dimensions of the nanowires.