The influence of impurity doping distribution in the channel region of p-type silicon nanowire FET has been studied using atomistic three-dimensional quantum simulator based on non-equilibrium Green's function formalism. The valence band has been modeled using a 6-band k.p Hamiltonian. Carrier transport has been treated in the coupled mode-space which considerably reduces the simulation time compare to real-space approach without losing the accuracy. We consider a FET with 10-nm gate length, 5×5 nm 2 cross-section and different doping densities.
This paper investigated the removal of acid red 94 and methylene blue from aqueous solution using iron-polyphenol nanomaterial synthesized by eucalyptus, rosemary and diosma leaves. The iron-poyphenol material was characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The kinetics, sorption equilibrium and thermodynamic data were analysed to understand dyes' removal behaviours. It found that ironpolyphenol nanomaterials synthesized by different plants present different characteristics regarding morphology, colour and adsorption capacity. TEM images showed that the freshly synthesized Fe-polyphenol material took the form of nanoparticles and then became cross-linked polymers in aged colloid. They can effectively remove acid red 94, but were less effective in removing methylene blue due to surface charge. The causes of these behaviours are discussed in this paper. It confirmed that Fe-polyphenol nanomaterial is a promising adsorbent for removing some contaminants from water.
We present the fabrication of GaSb quantum rings (QRs) on the GaAs (001) substrates by droplet epitaxy technique using solid-source molecular beam epitaxy (MBE). In droplet epitaxy process, Ga was deposited on GaAs surface to form liquid Ga droplets and then exposed to Sb flux for crystallization. The evolution of Ga droplets into GaSb QRs is discussed and tracked by means of reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM).
Nanotriangles of silver may be readily synthesized by wet chemical techniques and exhibit a strong localized surface plasmon resonance with light. Here we examine the complex resonances of nanotriangles in double- and triple-decker sandwich configurations.
We observe the enhancement of coherence due to localized surface plasmon resonance in random laser from gold nanoparticles. Higher coherence is obtained for random lasers with gold nanoparticles than with alumina nanoparticles.
Strong nonlinear interactions between the cantilever tip and sample may result in coupling of the cantilever modes, which may result in image artefacts. Such observations have been made in liquid AFM [1] and contact mode AFM [2, 3]. There are currently very few solutions to address this problem. While the displacement sensor can be calibrated to ignore contributions from the higher modes, this approach lacks robustness [4]. To mitigate these effects, we propose the application of modulated-demodulated control to suppress the higher modes. The modulated-demodulated control technique is advantageous as it reduces the bandwidth requirements of the baseband controller, simplifying the implementation of high-bandwidth controllers [5].
Local density of states and atomic structure of the stripped incommensurate phase, the √(3) ×√(7) phase and the 1 × 1 phase of a monolayer of Pb on Si(111) are characterized by scanning tunneling microscopy and spectroscopy. The dI/dV-images reveal congruent local density of states structures for the stripped incommensurate and the √(3) ×√(7) phase but suggest a hexagonal lattice of the local density of states for the 1×1 phase while the atomic structure consists of one more atom in the center of each hexagon. Vacancy defects and impurities show a depletion of local density of states for the stripped incommensurate and √(3) ×√(7) phase. Vacancies and impurities show an increase and no clear depletion in local density of states for the 1 × 1 phase, respectively.
Today various nano-moieties including nanoparticles, nanocubes, nanosticks, nanoflowers and nanoprimes have been synthesised. It is an interesting challenge to build nanostructures using those nano-moieties as blocks owing to their distinct properties and numerous applications. Herein, we demonstrate a smart way, self-assembling, to arrange nanoparticles and nanocubes into a line, sphere, network, bowl-bottom etc. The obtained anisotropic nanostructures have been employed to enhance the sensor sensitivity and to identify the hot-spot position for surface-enhanced Raman scattering (SERS).
Using all-atom classical molecular dynamics simulations, we have determined the structure of stereocomplexes composed of double-stranded helices of linear isotactic and cyclic syndiotactic poly(methyl methacrylate) in agreement with experimental X-ray diffraction data.
The potential for nanomaterials to interact with biological molecules has been under significant scrutiny, specifically, in their possible role as scaffolds for protein aggregation that can result in various amyloid diseases. Here, we employed classical molecular dynamics simulations to investigate the effects of graphitic carbon nanomaterials on the structure, dynamics and dissociation pathway of a previously identified preformed dimer of amyloidogenic apoC-II(60-70) peptide [1, 2]. Our results showed the dimer interacting with the graphitic nanoparticles through π-π interactions. Free energy of dissociation calculations showed that the dimer is weakly bound to the C60 nanoparticle, while it is more strongly interacting with the elongated nanomaterials, such as carbon nanotube and graphene. The significant curvature of the C60 surface induced an increase in peptide mobility, which contributed to the weaker binding and dissociation of the dimer from the C60 surface. This suggests that C60 can act as a potential inhibitor for fibril growth. On the other hand, the stronger interactions between the elongated carbon nanomaterials and the apoC-II(60-70) dimer resulted in a separation of the dimer with one strand remaining adsorbed on the surface of the nanomaterial during the in-silico pull-off experiment. This suggests that the interaction between the bound peptide and the flat graphitic surfaces is stronger than the interactions between the peptide strands themselves. Our results suggest that flat surface carbon nanomaterials present favorable binding substrates for aromatic-rich peptides, and thus have the ability to act as templates to mediate peptide self-assembly and fibril growth.
We present the first phase behaviour study of South Australian NAu.1 Nontronite clays (1) exfoliated in water and their orientation response in varying magnetic fields. We also describe a novel route for the grafting of water-soluble thermo-responsive polymers onto the edges of the nanoclay platelets.
This work focuses on the influence of Cu oxidation state on photocatalytic hydrogen generation by Cu/TiO 2 ·Hydrogen reduction was used to tailor the Cu oxidation state on the TiO 2. Cu + and/or Cu 0 appeared to be the more favourable oxidation state for generating H 2. Cu 2+ initially present on the TiO 2 was reduced to Cu + and/or Cu 0 during the photocatalytic process. Cu deposits on reduced Cu/TiO 2 catalysts were observed to be metallic Cu with a thin shell of CuO and its activity was greater than both bare TiO 2 and air-calcined Cu/TiO 2 . This enhancement could be attributed to metallic copper and improved Cu crystallinity.
Effects of electrodeposition time during the n-type CuInS2 thin film electrodes synthesis was studied in this work. All the CuInS2 thin film were fabricated via a single-step electrodeposition of Cu/In/S precursors on a transparent fluorine-doped tin oxide (FTO) substrate and calcined in a reducing gas atmosphere at 500 °C without using the toxic H2S gas for sulfurization. Thirty minute deposition time was the optimum condition based on the morphological features observed in the scanning electron microscope (SEM) images and the highest anodic photocurrent generated upon visible light illumination in the photoelectrochemical (PEC) test. The optical properties characterization revealed the CuInS2 thin films to have a direct bandgap of 1.42 eV, which confirmed the visible light active properties in the PEC performance.
For the large majority of materials science studies a good quality surface is extremely important. Especially, it is of great importance in case of electron backscatter diffraction (EBSD) where the information depth is as shallow as some tens of nanometres and this is the reason why this analytical method requires a damage- and oxide-free sample surface. The SC-1000 SEMPrep dual Ar ion beam workstation developed by Technoorg Linda Ltd., Hungary, is suitable for both surface polishing and slope cutting of solid state samples, preparing high-quality surfaces. These surfaces allow several types of SEM investigations including the surface sensitive EBSD analysis. The present paper demonstrates the operating principle of the SC-1000 SEMPrep apparatus and its outstanding abilities. Here we present Ar ion polishing of different conductive and nonconductive materials followed by high-resolution EBSD measurements. The average image quality (IQ) number of the Kikuchi patterns has been studied as a function of polishing angle and time in order to find the optimal polishing conditions. It has also been shown that using the optimal operation parameters high-quality surfaces can be obtained on different metallic and non-metallic materials.
Water soluble CdSe(S) quantum dots (QDs) were synthesized, modified and linked to antibodies, to give a CdSe(S) QD-antibody conjugated compound. The QD modification process was found to be effective by using X-ray photoelectron spectroscopy (XPS), circular dichroism and UV-visible and photoluminescence spectroscopies. The QDs were linked to the antibodies using ethyl-3-(dimethylaminopropyl)carbodimide (EDC) as the coupling agent and the stability and optical properties of both the QDs and QD-antibody conjugated compound were investigated.
It is well known that some polymers change their chemical, physical and mechanical properties, for example electrical resistance, capacity, size and shape in response to environmental stimuli through the absorption and desorption process of water. These changes can be converted into an electric signal which in turn can be used to monitor changes of the surrounding environment. In this study, we utilize superabsorbent polymer that can absorb and retain extremely large amounts of liquid relative to its own mass, with graphene to construct a moisture sensor. This moisture sensitive material and graphene can form hybrid hydrogels and after freeze-dried, they formed porous structures. The hybrid composites are excellent materials for high-resolution humidity sensing. The increased transduction is caused by the change in the effective electrical conductivity, which is governed by the varying percentages of air and water within the graphene/superabsorbent sensor. The change in the effective dielectric value will cause a measured change in conductivity that is proportional to the change in water absorbing.
We study a bilinear array of normal tunnel junctions in order to theoretically investigate the nature of correlations in space and time of the current. The bilinear array consists of two parallel rows of tunnel junctions which are capacitively coupled in either a straight or slanted coupling configuration. We use the kinetic Monte Carlo algorithm to simulate the time evolution of the array. We show that while slanted coupling modifies the correlated transport behaviour within the array compared to straight coupling, both circuit topologies show instability of the charge distribution during the conducting state.
In this paper we show a novel fabrication process capable of yielding arbitrarily-shaped optical oxygen sensor patterns at sub-micron resolution. The wafer-level process uses a thin-film sacrificial metal layer as intermediate mask, protecting the sensor material and enabling the use of electron beam lithography for sensor patterning. Feature sizes down to 500 nm are demonstrated and currently only limited by the optical system used for sensor readout. Gaseous oxygen detection using the patterned sensors shows Stern-Volmer behavior with a measured intensity ratio I100/I0 of 4.1. The process enables the integration of sensor patch arrays underneath single cells for laterally registered oxygen sensing in cell-culture applications.
Effect of nano-particles on bond strength of aluminium alloy 5050 produced by ARB was investigated. Experimental results indicated that nano-particles can significantly enhance the bond strength of aluminium alloys. Several kinds of nano-particles with different particle size were compared. The hardness of the particles and the particle size are the two factors that decide the strengthening effect. The results showed that 50 nm Al2O3 particles have the best strengthening effect.
In this work, we report the synthesis of 3-aminopropyltriethoxysilane (APTES) functionalized magnetite nanoparticles. Structure of the APTES functionalized nanoparticles was identified by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) while their size and morphology were determined by Transmission electron microscopy (TEM). Magnetic properties were measured using vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID) measurements. AC field induced heating ability of the nanoparticles was evaluated by the time-dependent calorimetric measurements using a RF generator. The functionalized nanoparticles were highly water soluble, monodispersed and superparamagnetic in nature with the blocking temperature at around 129 K. Cytotoxicity studies on MCF-7 cancer cells demonstrated that up to a dose of 10 mg/ ml, the APTES functionalized nanoparticles were nontoxic to the cells. The significant temperature rise of the functionalized magnetite nanoparticles upon exposure to AC magnetic field at 240 kHz frequency confirms their potential applicability for the magnetic hyperthermia treatment of cancer.
