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We report the miscibility characteristics of two components in a binary mixture of 9-phenyl anthracene (PA) mixed with stearic acid (SA) or polymethyl methacrylate (PMMA). The behaviour of surface pressure versus area per molecule isotherms reveal that the area per molecule decreases systematically with increasing molefractions of PA. The characteristics of areas per molecule versus molefractions and collapse pressure vs molefraction indicate that various interactions involved among the sample and matrix molecules. The interaction scheme is found to change with the change in surface pressure and molefraction of mixing. Scanning electron microscopic study confirms the aggregation of PA molecules in the mixed films. [ABSTRACT FROM AUTHOR]

Using a nm-level powder fabricated by a wet chemical method as precursor, the CeO2-doped WO3ceramics were prepared by the conventional solid state reaction at sintering temperatures from 600 to 1100?°C. The x-ray diffraction analysis reveals the coexistence of different WO3phases in the samples sintered at temperatures below 900?°C, whereas a single phase appears in the samples sintered above 1000?°C. No new Ce-W compound appears. As the sintering temperature increases, the electrical properties of the samples display an interesting transformation from linear to nonlinear behaviour. The measurements of scanning electron microscope, complex impedance and electrical stability indicate that a lot of grain boundary regions in the samples sintered at low temperatures strongly influences the electrical transportation. Therefore, the electrical nonlinearity is due to a basic process controlled by the back-to-back Schottky barriers at grain boundaries with suitable thickness as well as the coexistence of phases. [ABSTRACT FROM AUTHOR]

We report a study aimed at highlighting the mechanism of a new amorphous silicon crystallization phenomenon that originates from the perimeter of a germanium layer during low-temperature annealing (500°C). Results are reported on doped and undoped amorphous silicon films, with thicknesses in the range 40-200 nm, annealed at a temperature of 500 or 550°C. A comparison is made of crystallization arising from Ge and SiGe layers and the role of damage from a high-dose fluorine implant is investigated. Plan-view scanning electron microscope images show that perimeter crystallization is only present in amorphous silicon films with thicknesses ≤ 100 nm, and that the crystallization width increases with decreasing film thickness and increasing doping level. Cross-sectional scanning electron microscope images show that the perimeter crystallization originates from grains at the bottom of the amorphous silicon film. The perimeter crystallization phenomenon disappears when the amorphous silicon is implanted with fluorine and when an Si80%Ge20% layer is employed instead of germanium. The perimeter crystallization is due to the formation of large grains as a result of an increased growth rate of pre-existing grains and this is attributed to the strain generated by the thermal expansion of the germanium layer during anneal. [ABSTRACT FROM AUTHOR]

We proposed an object size measurement method from noisy scanning electron microscope (SEM) images with shot noise by utilizing the scale space approach. The proposed measurement algorithm consists of six steps: (1) specifying an object to be measured, (2) estimating the noise level, (3) constructing Gaussian and gradient scale spaces, (4) determining a starting scale for edge tracking, (5) edge tracking and (6) object size measurement. For the object size measurement, the model parameters of SEM images are estimated from regions segmented by edge positions at the finest scale. Then the appropriate scale for the object size measurement is automatically selected by estimated model parameters and an optimal scale parameter for smoothing filter in the Canny edge detector. And then, the object size is measured. We applied the algorithm to model SEM images and an SEM image. Though the processing time for our proposed method took about 13 times longer than that of the Canny detector, the range of the probability of extracting true edge positions was extended from 94% in the Canny detector to 80% in our method: the measurable region of the edge tracking was more extensive than that of the Canny detector. [ABSTRACT FROM AUTHOR]

A homogenized surface potential is desirable for the observation of a pre-irradiated insulating specimen using a scanning electron microscope because the residual surface potential may affect the imaging properties of the specimen. To homogenize the residual surface potential, the specimen should be subjected to the irradiation of an electron beam with the total electron yield greater than one. The expression of the equilibrium potential is derived based on the charge balance condition in the equilibrium state and the potential value is found to increase mainly with the secondary electron (SE) yield and the most probable emission energy of SEs. Further numerical calculations of SE trajectories show that affected by different surface potentials, SEs leave or return to the specimen surface to change the net charge flux into the specimen. This thereby increases the surface potential below the equilibrium potential and decreases that above the equilibrium potential, homogenizing the surface potential. [ABSTRACT FROM AUTHOR]

Intercalation of lithium into the vacant sites of a host compound can be achieved electrochemically using nonaqueous electrolytes. The use of aqueous electrolyte is less common because of the reactivity of many lithium intercalation compounds with water. Here, we propose that lithium could be intercalated into the manganese dioxide cathode in a battery using saturated lithium hydroxide as the electrolyte. The positive electrode reaction at MnO2 in this medium is shown to be lithium insertion rather than the usual protonation, and acceptable rechargeability is observed. Using X-ray photoelectron spectroscopy and scanning electron microscope analysis on the discharged cathode material we confirmed the presence of lithium ions in the host structure of MnO2. Further, the incorporation of small amounts (<3 wt % = weight percent) of titanium disulphide (TiS2) additive to the cell MnO2 cathode leads to a significant improvement in cell performance. [ABSTRACT FROM AUTHOR]

The influence of the doping level on the radiative recombination properties of GaSb:Se crystals has been investigated by cathodoluminescence (CL) microscopy and spectroscopy in the scanning electron microscope. CL images evidence a high dislocation density and dopant segregation around the dislocation cores in highly-doped crystals. A progressive reduction of the Se content leads to a lower dislocation density and a more uniform luminescence spatial distribution. CL spectra reveal the existence of three Se-related emission bands, centred in all the samples investigated at about 765, 740 and 719?meV, whose relative intensity is influenced by the doping level. Measurements carried out at different temperatures and excitation densities indicate that these bands can be attributed to transitions from the conduction band to deep acceptor levels. [ABSTRACT FROM AUTHOR]

A thin aluminium sheet comprising of large polycrystals is pulled in uniaxial tension and the resulting surface profile is measured in a scanning electron microscope. The surface profile near the grain boundaries reveals a local deformation pattern of width of a few micrometres and is strong evidence for strain gradient effects. Numerical analyses of a bicrystal undergoing in-plane tensile deformation are also studied using a strain gradient crystal plasticity theory and also by using a strain gradient plasticity theory for an isotropic solid. Both theories include an internal material length scale. An interfacial potential that penalizes the dislocations in crossing the grain boundary is included in the analysis. The results indicate that the surface profile is strongly dependent upon the choice of this potential and on the material length scale. [ABSTRACT FROM AUTHOR]

The environmental scanning electron microscope (ESEM) allows the sample to be imaged under a low pressure atmosphere. The ability to micromanipulate with precision within heated power systems in an ESEM will enable a greater understanding of the behaviour of materials at high temperature. Heating stages for ESEMs are commercially available but none include micromanipulation systems. Creating such a system is fraught with design problems. This is because the piezoelectric transducers, required to generate the precise range of movement within the heated environment, are unable to operate at temperatures exceeding about 90 °C and require thermal protection. Here, we have used a one-dimensional probe as a model of a three-dimensional manipulator. We have introduced a thermal break and a thermally insulating extension arm to protect the piezoelectric from heat. We have applied finite element analysis to test the design concepts before practical implementation. This ensures that the piezoelectric transducers in the costly practical devices are not placed at risk. The predictions have been validated with subsequent experimental work although there are some discrepancies to resolve. Examples of the movement of aluminium alloy grains and copper powder particles using the one-dimensional manipulator are given. [ABSTRACT FROM AUTHOR]

Water-soluble multiwalled carbon nanotubes (MWNTs) withtemperature-responsive shells were successfully prepared by grafting poly(N-isopropylacrylamide) (PNIPAM) from the sidewalls of MWNTs, via surface reversibleaddition–fragmentation chain transfer (RAFT) polymerization using RAFT agentfunctionalized MWNTs as the chain transfer agent. Thermogravimetric analysis (TGA)measurements showed that the weight composition of the as-grown PNIPAM polymers onthe MWNTs can be well controlled by the feed ratio (in weight) of NIPAM to RAFT agentfunctionalized MWNTs (MWNT-SC(S)Ph). The MWNT-g-PNIPAM has good solubility inwater, chloroform, and tetrahydrofuran (THF). Transmission electron microscope (TEM)and scanning electron microscope (SEM) images also showed that the MWNT-g-PNIPAMwas dispersed individually and eventually bonded with the polymer layer by surface RAFTpolymerization. The PNIPAM shell is very sensitive to a change of temperature. Thismethod could find potential applications by grafting other functional polymer chains ontoMWNTs. [ABSTRACT FROM AUTHOR]

Microfabricated grippers could be useful for the manipulation of nanoscopic andmicroscopic samples. A survey is presented of the force requirements for a microgripper tocomplete pick-and-place nanomanipulation tasks. We then demonstrate in situpick-and-place operations of nanowires inside a scanning electron microscope usingmicrofabricated electrostatically actuated grippers, and compare the theoreticallyestimated force requirements with the results of experimental tests of picking up nanowiresto evaluate how grippers and strategies for nanomanipulation can be optimized. [ABSTRACT FROM AUTHOR]

A method for three-dimensional reconstruction and imaging of surface topography in a scanning electron microscope (SEM) is briefly presented. The method is based on the ‘shape from shadows’ approach and is particularly suitable for relatively smooth surfaces, where stereoscopic methods may be less efficient. The authors used a quadruple secondary electron detector system and new numerical procedures for signal processing, which quite effectively curb main errors inherent in the method. Results of experiments prove that the vertical inaccuracy of the reconstructed shape may be reduced below 10% of the view field dimensions, if local surface inclination angles are less than 65°. Thus, a SEM equipped with the system designed by the authors may serve as a tool for the inspection and measurement of geometrical issues for several classes of micro-mechanical structures. [ABSTRACT FROM AUTHOR]

The luminescence of porous InP prepared by electrochemical etching is investigated by cathodoluminescence (CL) in a scanning electron microscope (SEM). Anodization causes a strong reduction of CL intensity as well as a blue spectral shift. Additional blue shift and enhancement of CL intensity is observed in samples cracked in vacuum by the effect of the SEM electron beam, which is explained by the reduction of the influence of surface states on the recombination mechanism. The relationship of the CL spatial distribution with the multilayer porous structure is described. [ABSTRACT FROM AUTHOR]

Large-scale fabrication of high-purity and uniform Zn nanowires was obtained via thermalevaporation. The resulting Zn nanowires were characterized and confirmed by means of anx-ray diffractometer, scanning electron microscope, transmission electron microscope andenergy-dispersive x-ray spectroscope. An analysis of the characterization indicates that thehigh yield uniform zinc nanowires have serpentine geometries, with lengths up to severalmicrometres and diameters about 50 nm. The selected area electron diffraction patternand high-resolution transmission electron microscopy image demonstrate perfectcrystallinity with the growth direction of [0001]. Owing to the low content of oxygen inthe as-prepared products, their photoluminescence spectrum was measured; itexhibits a significant blue shift. Up to now, such optical properties from zincnanowires have been little reported. [ABSTRACT FROM AUTHOR]

We report on the precise positioning of a carbon nanotube on an atomic force microscope(AFM) tip. By using a nanomanipulator inside a scanning electron microscope, anindividual nanotube was retrieved from a metal foil by the AFM tip. The electron beamallows us to control the nanotube length and to sharpen its end. The performance of thesetips for AFM imaging is demonstrated by improved lateral resolution of DNA molecules. [ABSTRACT FROM AUTHOR]

In this work the synthesis of zinc mercury selenide thin films (Zn1-xHgxSe) by electrodeposition is carried out. The films were deposited onto conducting glass (SnO2) substrates from an aqueous solution bath containing ZnSO4, HgCl2 and SeO2 at bath temperatures between 30 °C and 70 °C. The influence of deposition parameters such as electrolyte composition, deposition potential and temperature on the crystallinity and composition of the films is studied. It is found that the amount of mercury content in the solution bath and deposition potential control the composition and structure of the alloy films. The films were characterized by x-ray diffraction (XRD), energy dispersive x-ray analysis (EDAX), optical absorption and scanning electron microscope (SEM) studies. Photoelectrochemical solar cells studies using Zn1-xHgxSe thin films showed improved performance for annealed and etched electrodes and the results are discussed. [ABSTRACT FROM AUTHOR]

A large number of alumina nanofibres with strong photoluminescence was obtained in treated porous anodic alumina (PAA) film. The treatment includes three steps: doping the Cr into the high-purity aluminium by melting, anodizing the Cr-doped Al sheet to produce PAA followed by an etching process, and calcination. This routine yields a large number of alumina nanofibres with diameter about 80–150 nm, which were characterized by a scanning electron microscope and a transparent electron microscope. The obtained alumina nanofibres reveal very strong and sharp peaks in the photoluminescence spectrum, indicating their potential applications in nano-optics. [ABSTRACT FROM AUTHOR]

Two glass samples were prepared according to the molar formula (20%X–40%B2O3–40%SiO2), where X = CaO or CaF2. The glass was melted at 1300°C for 3 h until homogenous glass was obtained. The glass samples were heat-treated at 700°C for 2 h and at 850°C for different times. The green glass obtained has low dielectric constant and positive magnetic susceptibility. The molar volume, scanning electron microscope and differential thermal analysis studies showed that the crystallization rate increases with an increase in the sintering time. The replacement of CaO by CaF2 improves the physical properties of the glass. The existence of fluorine ions increases the electrical conductivity, magnetic susceptibility, molar volume, dielectric constant and effective overall reaction rate (κ). All measured properties have a random behaviour with sintering time due to phase separation and asymmetry of crystallization. [ABSTRACT FROM AUTHOR]

For the purpose of developing a recognition system for fine line patterns in the LSI, a statistical optimization method of the Canny edge detector for scanning electron microscope (SEM) images is proposed. The analysis of variance (ANOVA) is applied to the estimation of parameters in the SEM image: the grey level in the background, contrast, the line width and the noise level. These parameters are used to optimize statistically the Canny parameters, a scale parameter of the smoothing filter and a binarization threshold, by using noise characteristics of the SEM image. The proposed method is applied to model images and a real SEM image to show its validity. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the electron irradiation behaviour of an insulating material surface using a scanning electron microscope (SEM). The charging phenomena caused in two kinds of insulating materials (quartz and glass) by continuous electron irradiation have been observed. The discharging phenomena following switching off of irradiation have also been studied. The trapped charge density is determined by using the so-called electrostatic influence method based on the measurement, during and after the irradiation, of the influence and leakage currents using an arrangement adapted to the SEM. The experimental results reveal that the behaviour under irradiation of glass is entirely different from that of quartz. The trapped charges are found to be different, and the dependence of charging on the primary beam energy is discussed.The charging and discharging time constants have been determined accurately, and their evolution versus the mean electron penetration depth is qualitatively explained. Moreover, the role of secondary electron emission in the regulation mechanism of charging is underlined. [ABSTRACT FROM AUTHOR]

Images from scanning electron microscopy are now quite common and they can be of great value in archaeology. Techniques such as secondary electron imaging, backscattered electron imaging and energy-dispersive x-ray analysis can reveal information such as the presence of weevils in grain in Roman Britain, the composition of Roman coins and the burial of an Iron Age warrior on a sheep's fleece that has long since rotted away. [ABSTRACT FROM AUTHOR]

Biomimetic processes have attracted huge attention in recent years due to their significant applications in biomedical areas such as bone tissue engineering. In the present study, a biomimetic process was employed to form a nanocrystallite apatite coating on metal. A thin bone-like apatite layer was coated onto titanium (Ti) metals via an alkali pre-treatment. This was followed by immersion in a simulated body fluid. Analysis of the coating by thin film x-ray diffraction and scanning electron microscope has shown that the apatite layer grown in this way exhibits nanostructure and has similar stoichiometry to that of natural bone. It is observed that the thickness of the apatite layer increases as the immersion period increases. The growth kinetics and mechanism are also discussed. A cross-sectional study has also shown that a uniform coating of carbonate-containing apatite (hydroxyapatite) is firmly adhered on the Ti metal. The adhesion of the apatite layer on the Ti substrate was further confirmed by a shear test, which has shown an average value of 9.5 MPa. The bioactivity of the coating was finally examined by cell culturing experiments. The results have shown that the nanocomposite prepared using the present method possesses good mechanical properties and bioactivity. [ABSTRACT FROM AUTHOR]

In this paper, the frictional behaviours of single and multi-balls slid against micro-grooved silicon surfaces were investigated by using a micro-tribotester built inside a scanning electron microscope. Various micro-grooves were fabricated on the silicon surface to investigate the frictional behaviour with respect to the contact geometry between the surface asperities. Particularly, fast Fourier transform (FFT) analyses of the friction signals were performed with the motivation to assess the contact conditions. The primary objective of this paper was to understand better the asperity interaction condition at the sliding interface by analysing the frictional force signal using FFT. The experimental and numerical simulation results showed that the relative geometric ratio and the distribution of contact asperities on the surfaces could be predicted by the power and frequency spectra of the FFT analysis of the friction signal. Also, the frictional behaviour for multi-asperities was found to be the result of superposition of the frictional interaction of each asperity contact. It is expected that these observations will be utilized for the design of micro-structured surface with optimum geometry for better tribological performance. [ABSTRACT FROM AUTHOR]

The oxide shell of Al nanoparticles (Al NPs) prevents further reaction of Al/CuO nanothermites which reduces Al utilization efficiency and the performance of the nanothermites. However, the performance of Al/CuO nanothermites can be improved by adding ammonium perchlorate (AP). In this work, in order to confirm and explain the enhancement mechanism of AP on Al/CuO nanothermites, Al/CuO/NC and Al/CuO/NC/AP composites were prepared using the electrospray method. The composites were characterized by differential scanning calorimetry/thermogravimetric, x-ray diffraction, scanning electron microscope and transmission electron microscopy. Meanwhile, the ignition temperature and the time-resolved analysis of the rapid pyrolysis chemistry of the composites were tested using T-jump and time-of-flight mass spectrometry, respectively. The results show that Al NPs of Al/CuO/NC/AP composite are hollow compared to Al/CuO/NC composite after reaction. Al NPs and CuO NPs reduce the decomposition temperature and facilitate the rapid decomposition of the AP, and the decomposition products of the AP can destroy the oxidation layer of Al NPs. This result facilitates the further conduct of the thermite reaction. A mutually reinforcing relationship exists between the Al/CuO/NC composites and AP. [ABSTRACT FROM AUTHOR]

The thermal transport of monolayer MoS2, grown by chemical vapor deposition (CVD) method, was studied in this work. A novel approach was developed to transfer monolayer MoS2 onto suspended microelectrothermal system device, where a nano-manipulator in a scanning electron microscope was employed to accomplish the feat. This nano-manipulator-assisted transferring gives a high sample yield with relatively good sample quality compared to the traditional wet/dry transfer methods. Temperature-dependent thermal conductivity of monolayer MoS2 was measured by suspended-pads thermal bridge technique, with thermal conductivity value slightly lower than the exfoliated samples due to the phonon-defects scattering for CVD grown samples. Further extension of the current transfer method was demonstrated on few-layer graphite, where suspended graphite flakes that were free of surface ripples and with high thermal conductance were shown. [ABSTRACT FROM AUTHOR]

We report on the direct correlation between the structural and optical properties of single, as-grown core-multi-shell GaAs/In0.15Ga0.85As/GaAs/AlAs/GaAs nanowires. Fabricated by molecular beam epitaxy on a pre-patterned Si(111) substrate, on a row of well separated nucleation sites, it was possible to access individual nanowires in the as-grown geometry. The polytype distribution along the growth axis of the nanowires was revealed by synchrotron-based nanoprobe x-ray diffraction techniques monitoring the axial 111 Bragg reflection. For the same nanowires, the spatially-resolved emission properties were obtained by cathodoluminescence hyperspectral linescans in a scanning electron microscope. Correlating both measurements, we reveal a blueshift of the shell quantum well emission energy combined with an increased emission intensity for segments exhibiting a mixed structure of alternating wurtzite and zincblende stacking compared with the pure crystal polytypes. The presence of this mixed structure was independently confirmed by cross-sectional transmission electron microscopy. [ABSTRACT FROM AUTHOR]

The paper describes results of preliminary investigations of an octupole deflecting-focusing system, comprising a miniature unit of two diaphragms: a focusing diaphragm divided into eight segments with an octupole axial symmetry and a screening diaphragm. They are electrically isolated and can be mutually biased up to  ±4 kV with focusing voltage, while an isolated sample stands for the third electrode of a unipotential focusing lens. The octupole unit is steered by a digital, eight-channel electronic control system with isolated output circuits, enabling high-voltage bias of the octupole focusing diaphragm. The system is destined for handling an ion beam from a coaxial ion micro-source in scanning electron microscopy or an electron beam in a prospect electron optical micro-device. Preliminary tests conducted with a JSM-840 scanning electron microscope proved that the quasi-planar deflecting and focusing system (2.5 mm thick, at a distance of 3 mm to the sample) is capable at operating with acceptable imaging errors. Further, the electronic control system and the software fully meet the requirements. [ABSTRACT FROM AUTHOR]

A fabrication method for high quality flexible aluminum nitride piezoelectric thin films based on micro-nano fabrication technology is reported in this paper. Molybdenum (Mo)/aluminum nitride (AlN)/aluminum (Al) structure was prepared on silicon(100) by sputtering. Then, deep-reactive ion etching technology was used to remove the silicon material used for support, then the Mo/AlN/Al flexible sandwich film was obtained. The full-width at half-maximum of the AlN film (002) peak before and after removal of silicon was only 1.47° and 1.49°, respectively. No obvious cracks in the film under bending conditions were observed with a scanning electron microscope. Capacitance–voltage (C–V) test results showed that the capacitance curve of the sandwich structure was consistent with that of the double-sided Schottky junction. The flexible piezoelectric film with an active area of 2 × 2 mm2 exhibited an average peak-to-peak generated voltage of 0.6 V in energy harvesting tests, which indicates that the method could be used to fabricate high quality flexible energy collectors based on AlN film. The preparation scheme in this paper is compatible with integrated circuit processes and simple to implement, which lays a foundation for the wide application of flexible piezoelectric devices. [ABSTRACT FROM AUTHOR]

This study applied the combination of plasma-activated water (PAW) and mild heat (40 °C and 55 °C) for the decontamination of Bacillus cereus spores in rice (Oryza sativa L. ssp. japonica). In this study, PAW combined with 40 °C and 55 °C (PAW-40 and PAW-55) achieved 1.54 and 2.12 log10 CFU g−1 reductions of B. cereus spores in rice after 60 min exposure, which was significantly higher than the inactivation level (0.72 log10 CFU g−1) induced by PAW treatment alone. The assays for the leakage of intracellular contents (nucleic acids, proteins, dipicolinic acid-DPA) and the propidium iodide (PI) fluorescence probe confirmed that the combination of PAW and mild heat caused significant damages on the intact multilayered structure of B. cereus spores than the individual PAW did. The application of scanning electron microscope (SEM) and transmission electron microscope (TEM) provided a direct observation for the visible disruption of external structure and leakage of intracellular components caused by the combination of PAW and mild heat. Besides, the combination of PAW and mild heat caused no adverse effect on the texture and sensory qualities of the rice after cooking. These findings provide some knowledge for the application of PAW combined with mild heat for the decontamination of spores in rice. [ABSTRACT FROM AUTHOR]

Due to their ease of preparation, low cost and environmentally-friendly characteristics, zinc-type photocatalysts have attracted a lot of interest with regards to the photocatalytic degradation of organic pollutants. In this study, K+ doped ZnO (KZO) microcrystals were prepared from zinc acetate dehydrate and potassium hydroxide. X-ray diffraction analysis revealed the structure of the hexagonal wurtzite and the substitution of potassium ions in zinc oxide. A scanning electron microscope image showed the nanorod microstructure of prepared KZO crystallites. UV–visible analysis showed that the light absorption of KZO crystals expanded to the visible region and possessed a narrower band gap. In addition, the photocatalytic performance of KZO nanoparticles was evaluated. The results show that KZO possesses enhanced activity which is 3.45 times that of pure ZnO. This high performance in the photocatalytic degradation of organic pollutants can be ascribed to the band gap reduction, large surface area and improved transmission of charge carriers. [ABSTRACT FROM AUTHOR]

Introducing disorder into a periodic nanostructure can lead to specific optical behaviors. We present a method of anodic oxidation by adjusting the applied voltage and process time to introduce disorder to TiO2 nanotubes. The surface morphology of TiO2 was numerically investigated according to the morphologies measured with a scanning electron microscope by imaging processing and a statistical method. TiO2 nanotubes obtained under different fabrication conditions have various tube radii ranging from 20–40 nm and wall thicknesses ranging from 20–70 nm. We also evaluated the degree of disorder of the tube radius of the TiO2 nanotubes. The reflected scattering light distributions of laser sources were optically measured at different observing distances, which indicate that the presence of nanotubes enhances the scattering effect, reducing the scattered light intensity by more than 75%, and provide the relationship between the scattering effect and surface morphology of nanotubes. This discovery offers TiO2 nanotubes important application prospects in optical limiting and light confinement, such as stealth coating. [ABSTRACT FROM AUTHOR]

Self-catalyzed metal organic chemical vapor deposition (MOCVD) growth of Ga2O3 nanowires on GaN layers prepared on a sapphire substrate has been studied. Nanowire orientations are found to be growth temperature dominated. The vertical yields over total (VOT) curve shows a maximum peak beyond 70% around 480 °C, based on scanning electron microscope observations. X-ray diffraction patterns revealed a primary β-(-201) normal orientation of as grown nanowires all over the studied temperature interval. Further transmission electron microscopy characterization had confirmed β-(-201) normal axial orientation of these vertical nanowires, which have well crystallinity. The β-(010)//GaN(110) in-plane epitaxial relationship is consistent with reported Ga2O3 film/nanowire growth. Nanowires crystallized in β-[001] axial orientation were considered to be the inclined ones. Based on contrast experiments, the temperature dominated growth behavior is considered a thermodynamic process. The two observed crystalline orientation might have distinguishable but similar system energy, which results in coexistence of multi orientation nanowires over a large temperature span and an optimum temperature window for vertical β-(-201) normal orientation. The presented optimized β-Ga2O3 nanowire arrays with highest VOT close to 90% should effectively promote development of reliable high performance devices based on Ga2O3 nanowires. [ABSTRACT FROM AUTHOR]

We have developed a new non-destructive sub-surface interfacial imaging technique. By controlling the penetration depth of the incident electrons, through control of the electron beam acceleration voltage in a scanning electron microscope, we can observe sub-surface interfaces. The voltages for imaging are selected based on Monte Carlo electron flight simulations, where the two voltages have  >5% difference between the number of backscattered electrons generated in the layers above and below the buried interface under investigation. Due to the non-destructive nature, this imaging method can be used alongside an applied electrical current and voltage, allowing concurrent observations of the interfacial structures and transport properties, e.g. effective and active junction area, to occur. Magnetic tunnel junctions used in magnetic random access memory have been imaged and the data has been fed back to improve their fabrication processes. Our imaging method is therefore highly useful as both a quality assurance and development tool for magnetic memory and nanoelectronic devices. [ABSTRACT FROM AUTHOR]

In this paper, fabrication and testing of a miniaturized microcantilever-based particulate matter detector with integrated electrostatic on-chip ultrafine particle (UFP) separation and collection are presented. Mass added to the sensor causes a resonance frequency shift. To attract naturally charged particles, the cantilever is equipped with a collection electrode. In addition, a µ-channel is integrated, to improve the particle collection efficiency and to enable a size/mass-related particle separation. For electrical read-out, piezo-resistive struts are attached to the cantilever sidewalls near its clamping. This design offers high miniaturization potential, since no integration of transducing electronics on the cantilever beam is needed. The sensors are fabricated using Si bulk material and standard micromachining technology; the cantilevers have a thickness of 3  ±  0.5 µm, a width of 3.1  ±  0.3 µm, 5.9  ±  0.4 µm or 10.5  ±  0.4 µm and a length of 118.7  ±  0.8 µm, 168.8  ±  0.8 µm or 171.2  ±  1 µm, respectively. To this end, a front-side release process using cryogenic inductive-coupled plasma reactive ion etching was developed, which does not require additional sidewall passivation steps. Testing of the resonator function by operating the sensor inside a scanning electron microscope and reference measurements inside a temperature-controlled test chamber using synthetic carbon UFPs (~160 nm average mass concentration distribution) and a fast mobility particle sizer as a reference instrument were carried out. Here, the ability to detect low UFP mass concentrations in the range  <10 µg m−3 could be shown with a limit of detection of ~1 µg m−3 and a collection time of ~10 min. In addition, a voltage dependence of the collection efficiency was found at constant UFP-concentration conditions, which is an indication of size-selective UFP collection. [ABSTRACT FROM AUTHOR]

Solid-state nanopores have drawn considerable attention for their potential applications in DNA sequencing and nanoparticle analysis. However, fabrication of nanopores, especially those of diameter below 30 nm, requires sophisticated techniques. Here, a versatile method to controllably reduce the diameter of prefabricated large-size pores down to sub-30 nm without greatly increasing the effective pore depth from the original membrane thickness is shown. This method exploits carbon deposition achieved via hydrocarbon evaporation, induced by an incident beam of electrons, and subsequent dissociation of hydrocarbon to solid carbon deposits. The carbon deposition employs a conventional scanning electron microscope equipped with direct visual feedback, along with a stable hydrocarbon source nearby the sample. This work systematically studies how electron beam accelerating voltage, imaging magnification, initial pore size and membrane composition affect the process of pore size reduction. Secondary electrons generated in the membrane material are confirmed to be the main cause of the dissociation of hydrocarbon. Thicker carbon deposited on one side than on the other of the membrane results in an asymmetric nanopore shape and a rectifying ionic transport. A physico-phenomenological model combined with Monte Carlo simulations is proposed to account for the observed carbon deposition behaviors. [ABSTRACT FROM AUTHOR]

PbSe thin films of one-micron thickness were deposited on SiO2/Si wafers using chemical bath deposition method for IR detector applications. To sensitize the PbSe films for efficient mid-wave IR detection in the spectral range from 3 to 5 μm, oxidation at 460 °C and subsequent iodization at 350 °C were performed. The x-ray diffraction for as-grown PbSe shows poly-crystalline face-centered cubic NaCl type structure while Pb3O2(SeO3) oxide peak develops as a function of oxidation time. The existence of Se-rich structure may lead to p-type conduction. Scanning electron microscope and cross-sectional energy dispersive x-ray depth profile measurements after oxidation show the top layer of the film contains primarily Pb-Se-oxide while film at the bottom layer was PbSe. After sensitization, polytype trigonal 12R PbI2, Pb3O2I2 and PbSe were confirmed. The top layer of the sensitized PbSe film was found to be converted to primarily PbI2 while the bottom layer remained PbSe. However, during sensitization without oxidation, little PbSe remained because most of the PbSe was converted into PbI2. Also, the presence of metallic Pb nano-crystals with 10 nm diameter was detected in the sensitized film. [ABSTRACT FROM AUTHOR]

We present a novel framework for the fabrication of geometrically complex structures at the micro- and nano-scale which relies on the synergy of integrated computer-aided design and manufacturing systems (CAD/CAM) and focused ion beam (FIB) technology in a scanning electron microscope. Here we utilise industry standard G-code syntax, for the first time, to FIB machining by designing geometries with CAD, defining machining strategies and exporting G-codes with CAM and generating a coordinate list-based beam path by using a custom-built interpreter program. This allows the fabrication of complex structures from CAD models using syntax which is readily understood in the general fabrication industry. The use of G-code allows optimization of the beam path towards a reduction of beam blanking operations and tracing of contours, leading to minimized re-deposition of material. We give a detailed description of the method, use an application example to demonstrate advantages and prospects of the approach and provide the free and open-source interpreter program CAM2FIB for application of this method. We contrast and compare various existing available milling strategies and demonstrate the versatility of G-code based programming. [ABSTRACT FROM AUTHOR]

This paper reports on the recycling of expanded polystyrene (EPS) waste to be repurposed as EPS nanofibrous mats for air filtration applications. The EPS nanofibrous mats were prepared via electrospinning technique. The EPS solutions for producing the mats were made by dissolving the EPS waste in dimethylformamide (DMF) and d-limonene solvents. The mixing ratio of DMF and d-limonene solvents were varied to obtain EPS solutions with different surface tension and viscosity. As a result, different fiber morphology (smooth fiber, wrinkled fiber, and beaded fiber) and diameter ranging from 314 nm to 3506 nm were obtained. The synthesized EPS nanofibrous mats were characterized by scanning electron microscope, Fourier-transform infrared spectroscopy, x-ray diffraction spectroscopy, differential scanning calorimetry, mechanical strength, porosity, and water contact angle measurement apparatus. The mechanical strength measurement exhibited that the beaded fiber had the highest tensile strength and the lowest elasticity compared to wrinkled and smooth fiber. The water contact angle measurement showed that the EPS nanofibrous mats were classified as ultra-hydrophobic, which was a good criterion for air filter media. Some filtration parameters of the EPS nanofibrous mats were measured, including particle collecting efficiency, pressured drop, and quality factor. The particle collecting efficiency of each EPS nanofibrous mats was measured using monodisperse polystyrene latex (PSL) particles and PM2.5 from burning incense as the test particles. The EPS nanofibrous mats had a high collecting efficiency (up to 99.99%) and had a low pressure drop (below 70 Pa) for the face velocity of 5.4 cm s−1. The quality factor of the EPS nanofibrous mats reached 0.10 for PSL filtration and 0.16 for PM2.5 filtration. Overall, the EPS nanofibrous mats with controlled morphology were suitable to be used as air filtration media with high mechanical strength, ultra-hydrophobic surface, and high quality factor. [ABSTRACT FROM AUTHOR]

Knowledge of deformation and failure mechanisms at micro- to nano-length scales is important for the prediction of material behavior as well as the development of new materials with desired properties. In situ multiaxial testing with scanning electron microscopes (SEM) can reveal physical deformation mechanisms under realistic multiaxial loading conditions. Although in situ SEM testing has gained traction in recent years, there is currently no multiaxial in situ SEM testing stage available with axial-torsional loading capabilities which can generally be used in any SEM. In this study, we report the development of a multiaxial miniature testing system (MMTS) with a unique capability for performing axial-torsional testing of a tubular specimen with a 1–2 mm outer diameter, inside most SEMs. The different challenges of developing a multiaxial in situ SEM testing stage, such as small load frame size, appropriate specimen position, high vacuum compatibility of MMTS load frame components, as well as the development of installation accessories, were addressed. A custom SEM stage door was developed for the MMTS load frame. Verification tests have confirmed the successful development of the MMTS for in situ SEM testing. In addition, digital image correlation was used with recorded SEM images during the test to determine the surface strain. [ABSTRACT FROM AUTHOR]

We report on mask-less, high resolution etching of diamond surfaces, featuring sizes down to 10 nm. We use a scanning electron microscope (SEM) together with water vapor, which was injected by a needle directly onto the sample surface. Using this versatile and low-damage technique, trenches with different depths were etched. Cross sections of each trench were obtained by focused ion beam milling and used to calculate the achieved aspect ratios. The developed technique opens up the possibility of mask- and resist-less patterning of diamond for nano-optical and electronic applications. [ABSTRACT FROM AUTHOR]

Circulating tumor cells (CTCs) are important for the detection and treatment of cancer. Nevertheless, a low density of circulating tumor cells makes the capture and release of CTCs an obstacle. In this work, TiO2 nanopillar arrays coated with gelatin film were synthesized for efficient capture and undamaged release of circulating tumor cells. The scanning electron microscope and atomic force microscope images demonstrate that the substrate has a certain roughness. The interaction between the cell membrane and the nanostructure substrate contributes to the efficient capture of CTC (capture efficiency up to 94.98%). The gelatin layer has excellent biocompatibility and can be rapidly digested by matrix metalloproteinase (MMP9), which realizes the non-destructive release of CTCs (0.1 mg ml−1, 5 min, nearly 100% release efficiency, activity 100%). Therefore, by our strategy, the CTCs can be efficiently captured and released undamaged, which is important for subsequent analysis. [ABSTRACT FROM AUTHOR]

Recent advances in helium ion microscopy (HIM) have enabled the use of fine-focused He+ beams to image and shape materials at the nanoscale. In addition to traditional ion milling, the beam can also be used to induce reactions, such as cross-linking, in films of organic molecules. Here, we compare the use of focused ion and electron beams to fabricate spatially-defined cross-linked features in nanometre-thick films of tetracene. Ion and electron beam treatments were performed using the focussed energetic beams in a HIM and a scanning electron microscope, respectively. The patterned samples were analysed by optical microscopy, HIM, atomic force microscopy and nanoindentation. For samples fabricated using both energetic beams, the total deposited particle dose could be used to modify the optical properties, thickness and hardness of the dosed regions. X-ray photoelectron spectroscopy revealed that the dosed regions exhibited a higher sp3 content, consistent with crosslinking; rinsing in solvent showed that the patterned regions were insoluble and could be isolated by removing the unmodified film through dissolution. These molecular nanopatterns demonstrate the promise for ultrahigh resolution chemical lithography, and for fabrication of nanocomponents with tailored physical properties. [ABSTRACT FROM AUTHOR]

Practical applications of the MgB2 prepared by the in situ method are usually limited because of the pores formed by the volatility of Mg. In order to improve the performance of MgB2 bulks, MgB2 bulks were fabricated through an in situ synthesis method with composites of B powder, Mg powder, and 10–100 wt% Mg(BH4)2 powder. The superconducting properties and grains structure of these MgB2 bulks were investigated, such as onset superconducting transition temperature (Tc), critical current density (Jc), porosity, resistivity (ρ), and grain connectivity. For the MgB2 bulk prepared from 80 wt% Mg(BH4)2 powder added composites, the Jc (1 T) value at 5 K was 4.1 × 105 A cm−2 and the onset Tc value was 37.5 K. Moreover, the microstructure of these MgB2 bulks was also analyzed using scanning electron microscope (SEM). The MgB2 bulk with less pores can be prepared with moderate Mg(BH4)2 powder added composite as precursor. The composites also provide raw materials for preparing high-quality in situ MgB2 superconducting wires. [ABSTRACT FROM AUTHOR]

Modified g-C3N4 samples (g-X, where X corresponds to the number of hours of acid treatment of the melamine) with outstanding photocatalytic performance were prepared by using hydrochloric acid-treated melamine as a precursor and calcining at 550 °C for 2 h. An x-ray diffractometer, field-emission scanning electron microscope, infrared spectrometer, N2 adsorption–desorption test, x-ray photoelectron spectroscopy, and ultraviolet–visible diffuse–reflectance spectroscopy analysis were carried out to characterize the phase composition, microstructure, chemical structure, specific surface area (SSA), chemical states, elemental composition and optical properties of the samples, respectively. The photocatalytic performance of the samples was evaluated by degrading the Rhodamine B (RhB) aqueous solution. The results showed that the crystal structure and vibration bands of melamine changed due to the reaction with hydrochloric acid. The crystallinity and grain size of g-C3N4 in g-X (X = 1, 2, 4, 6, 8, 10) reduced, and the SSA values of g-X increased compared to that of the g-0 sample, which was synthesized from pristine melamine. The g-X samples exhibited excellent photocatalytic activity towards degradation of RhB compared to g-0. The photocatalytic activity of the g-X samples increased gradually as the acid treatment time of the melamine increased from 1 h to 2 h, and then decreased gradually with the extension of the acid treatment time. The rate constant (k) values of g-X are higher than that of g-0. g-2 presented the highest rate constant (k = 0.052 min−1), which was 5.5 times higher than that of g-0. The improved photocatalytic activity of the g-X samples was attributed to the higher SSA value, the appearance of surface defects, the outstanding photo-carrier separation efficiency and stronger light harvesting ability of g-X, with the last two factors being more significant. Acid treatment of melamine is helpful in the preparation of high performance g-C3N4 photocatalyst, and the microstructure and photocatalytic performance of g-C3N4 were affected significantly by the acid treatment time. [ABSTRACT FROM AUTHOR]

We present a simulation study on the peeling of carbon nanotubes bundles interacting with a flat substrate, represented by the back surface of an atomic force microscopy cantilever. A defected sample, acquired in situ using a scanning electron microscope, was investigated under different peeling configurations by finite element method simulations. The coupled computational-experimental analysis let to identify the position and the entity of a structural defect by means of reverse image correlation problem. By exploiting this defective fiber it was also possible to quantify, as indirect measure, the friction and adhesion forces between the bundle and the substrate of few pN magnitude, otherwise difficult to measure with the resolution of currently available instruments. The proposed approach can be useful to study the tribology-induced mechanical behavior of one-dimensional nanostructures as well as for real-time identification and monitoring of nanodefects for industrial applications, such as nanoelectronics. [ABSTRACT FROM AUTHOR]

Silicon monoxide (SiO) has been considered as one of the most promising anode materials for next generation high-energy-density Li-ion batteries (LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite (SiO@C/G) composite anode materials, with designed capacity of , are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with 15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25 °C and 90.1% at 45 °C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope (SEM) and electrochemistry impedance spectroscopy (EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode. [ABSTRACT FROM AUTHOR]

Preparing counter electrode (CE) with low cost and high catalytic activity is a method for improving the photovoltaic performance of quantum dot-sensitized solar cells (QDSSCs). Here, ZIF-67 thin films are prepared on an Ni sheet and FTO-conducting glass substrate by electrophoretic deposition at different applied electric fields, and then efficient CoS2/Ni and CoS2/FTO electrodes are obtained by vulcanizing the ZIF-67 thin films using thioacetamide. The prepared CoS2 thin films are characterized by the measurements of the scanning electron microscope, x-ray photoelectron spectroscopy, x-ray powder diffraction and Fourier transform infrared spectra. Further, the CoS2/Ni and CoS2/FTO thin films are used as CEs to fabricate QDSSCs. Photocurrent-voltage curves, electrochemical impedance spectroscopies and Tafel curves are measured to evaluate their photoelectrochemical properties. The short-circuit photocurrent value of QDSSC, based on the CoS2/Ni CE, is significantly improved compared with that of the cell based on the CoS2/FTO, and thus the light-to-electric conversion efficiency increases from 1.95% to 3.24%. The enhancement mechanism of electrocatalytic activity and photovoltaic performance of CE prepared on an Ni sheet are analyzed to be less resistant than an Ni sheet and have a higher charge transfer rate between CE and electrolyte. [ABSTRACT FROM AUTHOR]

The downscaling of device dimensions in semiconductor manufacturing has meant that critical defect sizes have become smaller and smaller. This makes it more likely that the highly sensitive optical wafer inspection tool used for detecting small defects will erroneously detect process variations as defects, and generate a large amount of ‘nuisance’ information. Therefore, the scanning electron microscope (SEM)-based review tool used needs to automatically discriminate between defects and nuisance information. To identify nuisance information, the absence of defects in the SEM image needs to be accurately detected through an inspection process using the review tool. We propose a defect detection method using (a) the integration of multiple comparison detection (IMCD) results to minimize the number of defect candidates and (b) discrimination based on a normal patch image model (DNPM) to judge whether a candidate is a defect or normal. An evaluation using SEM images of a processed wafer revealed that combining the IMCD and DNPM methods achieves a nuisance information discrimination rate of 84.4% and a defect detection rate of 93.3%, which are higher rates than those achieved by the one-class support vector machine. The proposed methods automatically collect defect images efficiently even when a great deal of nuisance information is produced by the optical wafer inspection tool, and enable manual visual checks to be reduced. [ABSTRACT FROM AUTHOR]

In our previous study, an instrument for characterizing mechanical properties under multi-mechanical load and multi-physical field coupling conditions was designed and constructed. Given the structural interference, the linear and shear strains in tension–torsion coupling testing were measured indirectly using linear and circular grating encoders rather than the extensometers in a conventional material testing machine. Accordingly, to correct the experimental curves measured using grating encoders, a correction method was proposed using equations based on the analysis of specimen geometry and instrument structure by elasticity theory. The feasibility of the correction method under single load and tension–torsion coupling loads were verified by the contrast tests among curves of grating encoders’, curves of extensometers, and results of a digital image correlation (DIC) measuring system. Test results illustrate that the correction method can convert the displacement measured using grating encoders to the deformation of the specimen in the elastic range, and the measuring error of elastic moduli can be reduced to approximately 1/5–1/50 of the original measurement results. The defect on accuracy of this instrument, which is incompatible with extensometers, can be compensated. Overall, the main sources of error in these devices are the deformation of the load cell and that on the non-gage section of specimen. This conclusion can provide guidance on the design of other similar devices. [ABSTRACT FROM AUTHOR]

The accurate determination of the geometrical features of quasi one-dimensional nanostructures is mandatory for reducing errors and improving repeatability in the estimation of a number of geometry-dependent properties in nanotechnology. In this paper a method for the reconstruction of length and spatial orientation of single nanowires (NWs) is presented. Those quantities are calculated from a sequence of scanning electron microscope (SEM) images taken at different tilt angles using a simple 3D geometric model. The proposed method is evaluated on a collection of SEM images of single GaAs NWs. It is validated through the reconstruction of known geometric features of a standard reference calibration pattern. An overall uncertainty of about 1% in the estimated length of the NWs is achieved. [ABSTRACT FROM AUTHOR]