Abstract: Summary: Helium ion milling of suspended siliconnitride thin films is explored. Milled squares pat-terned by scanning helium ion microscope are sub-sequently investigated by atomic force microscopyand the relation between ion dose and milling depthis measured for both the direct (side of ion inci-dence) and transmission (side opposite to ion in-cidence) regimes. We find that direct-milling depthvaries linearly with beam dose while transmission-milling depth varies with the square of the beamdose, resulting in a straightforward method of con-trolling local film thickness. SCANNING 00: 1–6,2012. C 2012 Wiley Periodicals, Inc. Key words: helium ion microscope (HIM), atomicforce microscope (AFM), ion milling, membrane,thinning Introduction The helium ion microscope (HIM) is a promisingyoung technology for high-resolution imaging (Mor-gan etal. ,2006;Scipioni etal. ,2008;Ramachandra etal. ,2009).Thisinstrumentusesanatomicallydefinedmetalsourcetoproduceacoherenthelium(He)beamwith high brightness and small probe size. Through

Abstract: The nanoarchitecture and surface roughness of metallic thin films prepared by magnetron sputtering were analyzed to determine the topographical statistics that give the optimum description of their nanoarchitechture. Nanoscale topographical profiles were generated by performing atomic force microscopy (AFM) scans of 1 μm × 1 μm areas of titanium and silver films of three different thicknesses (3 nm, 12 nm, and 150 nm). Of the titanium films, the 150-nm film had the highest average roughness (R(a) = 2.63 nm), more than four times that of the 3-nm and 12-nm titanium films. When silver films were coated on top of 150-nm titanium films, the average roughness increased further; the 3-nm (R(a) = 4.96 nm) and 150-nm (R(a) = 4.65 nm) silver films average roughnesses were approximately twice that of the 150-nm titanium film. For topographical analysis, seven statistical parameters were calculated. These parameters included commonly used roughness measurements, as well as some less commonly used measurements, in order to determine which combination of parameters gave the best overall description of the nanoarchitecture of the films presented. Skewness (R(skw)), surface area increase (R(sa)), and peak counts (R(pc)) provided the best description of horizontal surface dimensions, and in conjunction with vertical descriptors R(a) and R(q) gave the best characterization of surface architecture. The five roughness parameters R(a), R(q), R(skw), R(sa), and R(pc) are proposed as a new standard for describing surface nanoarchitecture.

Abstract: Monte Carlo simulation methods for the study of electron beam interaction with solids have been mostly concerned with specimens of simple geometry. In this article, we propose a simulation algorithm for treating arbitrary complex structures in a real sample. The method is based on a finite element triangular mesh modeling of sample geometry and a space subdivision for accelerating simulation. Simulation of secondary electron image in scanning electron microscopy has been performed for gold particles on a carbon substrate. Comparison of the simulation result with an experiment image confirms that this method is effective to model complex morphology of a real sample.

Abstract: In this report, helium ion microscopy (HIM) is used to study the micro and nano-structures responsible for structural color in the wings of two species of Lepidotera from the Papilionidae family: Papilio ulysses (Blue Mountain Butterfly) and Parides sesostris (Emerald-patched Cattleheart). Electronic charging under the beam of uncoated scales from the wings of these butterflies is successfully neutralized, leading to images displaying a large depth-of-field and a high level of surface detail, which would normally be obscured by traditional coating methods used for scanning electron microscopy (SEM). The images are compared to those from variable pressure SEM, demonstrating the superiority of HIM at high magnifications. In addition, the large depth-of-field capabilities of HIM are exploited through the creation of stereo pairs which allows the exploration of the third dimension. Furthermore, the extraction of quantitative height information which matches well with cross-sectional transmission electron microscopy (TEM) measurements from the literature is demonstrated.

Abstract: Structure of bacterial biofilms may be investigated using several variants of scanning electron microscopy (SEM) We apply lyophilization to prepare nitrifying bacterial biofilm for conventional SEM imaging in high-vacuum mode (CSEM) We therefore replace standard biofilm fixation in glutaraldehyde cross-linking, ethanol dehydration, and critical-point drying (CPD) with less-invasive low-temperature drying by sublimation in vacuum We compare this approach with: (1) standard preparation with glutaraldehyde fixation, ethanol dehydration, and CPD before CSEM, (2) cryo-sputter preparation of rapidly frozen biofilm in hydrated state (cryo-SEM), and (3) in situ observation without any sample pretreatment in environmental SEM Combined imaging with these modalities revealed two distinct immobilization patterns on the polyurethane foam: (1) large irregular aggregates (flocs) of bacterial biofilm that exist as irregular biofilm fragments, rope-like structures, or biofilm layers on the foam surface; (2) biofilm threads adherent to the surface of polyurethane foam Our results indicate that lyophilization was suitable for preservation of bacterial cells and many forms of structure of extracellular matrix The lyophilized material could be imaged with high resolution (using CSEM) to generate structural information complementary to that obtained with other SEM techniques

Abstract: Although helium ion microscopy (HIM) was introduced only a few years ago, many new application fields are emerging. The connecting factor between these novel applications is the unique interaction of the primary helium ion beam with the sample material at and just below its surface. In particular, the HIM secondary electron signal stems from an area that is extremely well localized around the point of incidence of the primary beam. This makes the HIM well suited for both high-resolution imaging and high-resolution nanofabrication. Another advantage in nanofabrication is the low ion backscattering fraction, which leads to a weak proximity effect. The subnanometer probe size and the unique beam-materials interactions have opened new areas of research. This review presents a selection of studies conducted on a single instrument. The selection encompasses applications ranging from imaging to nanofabrication and from fundamental academic research to applied industrial developments. © 2012 Wiley Periodicals, Inc.

Abstract: High-entropy alloys have been studied extensively for their excellent properties and performance, including outstanding strength and resistance to oxidation at high temperatures. This study employed molecular dynamics simulation to produce a high-entropy alloy containing an equal molar ratio of Al, Co, Cr, Fe, and Ni and investigated the tribological behavior of the material using a diamond tool in a vacuum environment. We also simulated a AlCoCrFeNi high-entropy alloy cooled from a high temperature molten state to 300 K in a high-speed quenching process to produce an amorphous microstructure. In a simulation of nanoscratching, the cutting force-distance curve of high-entropy alloys was used to evaluate work hardening and stick-slip. An increase in temperature was shown to reduce the scratching force and scratching resistance. Nanoscratching the high-entropy alloy at elevated temperatures provided evidence of work hardening; however, the degree of work hardening decreased with an increase in temperature. And it can also be found that when the temperature is higher, the fluctuation of the cutting force curve is greater.

Abstract: A statistical model describing signal-noise generation and development along the signal formation process in a standard scanning electron microscope (SEM) using an Everhart–Thornley secondary electron detector is derived. Noise in the detector signal is modeled to originate from a cascade of five signal conversion stages. Based on the derived model, general conclusions are drawn concerning the total signal-to-noise ratio (SNR) at each stage, and the influence of each stage on the total SNR of the detector signal. The model is furthermore applied to a real-world SEM, and verified by experimental data. SCANNING 34: 137–144, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: Broccolini (Brassica oleracea Italica × Alboglabra) is a hybrid between broccoli and Gai Lan, also known as Chinese broccoli and Chinese kale. The aim of this study was to assess the antitumor activity of Broccolini leaf flavonoids (BLF). Cell growth inhibition was evaluated using a standard colorimetric MTT assay, cellular morphology was observed using phase contrast microscopy and flow cytometry was introduced to further investigate cells apoptosis effect. The results showed that BLF possess a dose-dependent antiproliferative effects on four human cancer cell lines (SW480, HepG2, Hela, and A549) and apoptosis induction activity on SW480 cell line. Thus, the hybrid species Broccolini could be considered as a functional vegetable with potential in assisting for the treatment of four human cancers examined here.

Abstract: In this study, nanoscratching and nanomachining were conducted using an atomic force microscope (AFM) equipped with a doped diamond-coated probe (DDESP-10; VEECO) to evaluate the fabrication of nanopatterns on hard, Cr2N/Cu multilayer thin films. The influence of normal force, scratch speed, and repeated scratches on the properties of hard multilayer thin films was also investigated. The nanoscratch experiments led researchers to establish a probe preparation and selection criteria (PPS criteria) to enhance the stability and accuracy of machining hard materials. Experimental results indicate that the depth of grooves produced by nanoscratching increased with an increase in normal force, while an increase in the number of scratches in a single location increased the groove depth but decreased friction. Therelationships among normal force and groove depth more closely resembled a logarithmic form than other mathematical models, as did the relationship between repeated scratching and its effect on groove depth and friction. The influence of scratch speed on friction was divided into two ranges. Between 0.1 and 2 µm/s, friction decreased logarithmically with an increase in scratch speed; however, when the speed exceeded 2 µm/s, the friction appeared stable. In this study, multilayered coatings were successfully machined, demonstrating considerable promise for the fabrication of nanopatterns in multilayered coatings at the nanoscale. SCANNING 34: 51–59, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: We present here a hybrid approach to modeling helium-ion lithography that combines the power and ease-of-use of the Stopping and Range of Ions in Matter (SRIM) software with the results of recent work simulating secondary electron (SE) yield in helium-ion microscopy This approach traces along SRIM-produced helium-ion trajectories, generating and simulating trajectories for SEs using a Monte Carlo method We found, both through simulation and experiment, that the spatial distribution of energy deposition in a resist as a function of radial distance from beam incidence, ie the point spread function, is not simply a sum of Gauss functions

Abstract: In contrast to colonoscopy biopsy, which contains several disadvantages such as bleeding, sampling error, crush artifact, and time-consuming pathological procedure, multiphoton microscopy (MPM) enables direct noninvasive visualization of tissue architecture and cell morphology in live tissues without the administration of exogenous contrast agents. We performed a proof-of-principle study to evaluate the feasibility of using MPM to make real-time noninvasive optical diagnosis of colorectal cancer by investigating 30 fresh, unfixed, and unstained full-thickness colorectal specimens. We found that MPM images demonstrated irregular tubular structures, reduced stroma, and cellular and nuclear pleomorphism in the cancerous tissues. Cancer cells, characterized by irregular size and shape, enlarged nuclei, and increased nuclear-cytoplasmic ratio, were clearly observed in MPM images, which were comparable to golden standard hematoxylin-eosin staining images. Our findings showed that MPM had the potential to make real-time noninvasive optical diagnosis of colorectal cancer. With miniaturization and integration of colonoscopy, MPM has a promising future in real-time noninvasive "optical biopsy" for colorectal cancer.

Abstract: In this study, we deposited isolated magnetosomes from magnetotactic bacteria Magnetospirillum strain AMB-1 onto solid surfaces using spin coating (SC) and drop coating (DC) techniques. Four imaging techniques have been used to visualize the sample structure: scanning and transmission electron microscopy (SEM, TEM), atomic and magnetic force microscopy (AFM, MFM). Additionally, dynamic light scattering was applied to measure the hydrodynamic radius of agglomerated/aggregated magnetosomes in a liquid environment. This manuscript discusses observed differences between structures obtained by two deposition techniques, i.e. possible interactions and factors responsible for magnetosomes' formation, their morphology on surfaces as a result of agglomeration and aggregation phenomena. Moreover, topography and homogeneity of obtained structures as well as thickness of protein-based membrane were also examined and described. Using high-resolution TEM, we analyzed the size of magnetic cores, their crystal structure and quality. We found that the SC technique provides a homogenous layer of magnetosomes and hydrophilization of silicon surfaces improves the deposition of magnetosomes. However, due to strong hydrogen interaction to the hydrophilic silicone surface, the organic membrane of magnetosomes is mostly flattened. As a matter of fact, the size distributions of magnetosomes deposited by SC and DC techniques (logarithmic-normal tendency) differ from the Feret diameter distribution (normal). Furthermore, our study confirms the good crystalline quality of magnetosomes' cores. It also shows that they are magnetic in the all their volume.

Abstract: The goal of this study was to examine the pathophysiological changes to erythrocytes in multiple myeloma (MM) patients at a nanometer scale. We hypothesize that studying changes in red blood cells may be important for early diagnosis and effective treatment of MM. Blood samples were taken from ten healthy volunteers and ten MM patients before and after treatment. Changes in the morphological and biomechanical properties of the erythrocytes were studied at a nanometer scale with atomic force microscopy (AFM). There were dramatic deformations in the overall shape and surface membrane of the erythrocytes from pre- and post therapeutic MM patients compared with the healthy controls. Healthy and pathological MM erythrocytes could be distinguished by several morphologic parameters, including the width, length, length to width ratio, valley, peak, valley-to-peak, standard deviation, and surface fluctuation. The effectiveness of disease treatment could also be evaluated by studying these red blood cell parameters. AFM was able to detect noticeable morphological differences in the red blood cells from MM patients compared with healthy controls. Therefore, erythrocyte morphology is an important parameter for diagnosing MM, as well as evaluating the efficacy of disease treatment.

Abstract: Chlorhexidine (CHX) has been reported to reduce self-degradation of collagen fibrils by inhibiting host-derived protease activity in demineralized dentin. Theoretically, if the collagen fibril scaffold of demineralized dentin maintains its original crosslinkage pattern on treatment with CHX and appropriate supplementation with necessary mineral sources, dentin remineralization may occur in demineralized lesions. In this study, we provide direct mechanical and micromorphological evidence for the ability of CHX to promote remineralization of demineralized dentin. Specifically, with respect to demineralized dentin blocks treated with different concentrations of CHX (0.02–2%) and stored in simulated body fluid, we have observed a significant increase in the elastic modulus of dentin treated with relatively high concentrations of CHX (0.2 and 2%) as storage time increased, whereas the elastic modulus of the non-CHX treated control group decreased. We have also observed a dense mineral deposition along collagen fibrils in the dentin group treated with 0.2 and 2% CHX via field emission scanning electron microscopy. SCANNING 34: 151–158, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: Summary The purpose of this study was to compare the surface morphology and surface hardness of five materials 24 h after filling, in conditions of 100% humidity, and fetal bovine serum. The five materials were ProRoot Mineral Trioxide Aggregate (MTA), Super-EBA, Intermediate Restorative Materials (IRM), Zinc Oxide Eugenol (ZOE), and Amalgam. The microhardness of these materials was evaluated by Vickers microhardness test, and their morphologies were compared by using scanning electron microscopy (SEM). To evaluate the microhardness, the mixed five materials were measured with Vickers microhardness test. Differences between the experimental groups were analyzed by two-way ANOVA and Duncan's multiple comparison tests. All analyses were performed using the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL). For the microstructural morphological evaluation, the cross cut and root-end cavity prepared surfaces followed by retrograde filling with five different materials were observed under a Scanning Electron Microscope (Steroscan 440; Leica, Cambridge, England) at ×500. To summarize, Super EBA was less influenced by storage medium than the other materials, especially MTA. However, further long-term studies considering other factors, such as biocompatibility (i.e. cellular toxicity) and retention, are needed to be collaborated with these findings in the clinical context. SCANNING 34: 207-214, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: Summary: A diagnostic approach is developed and implemented that provides clear feature definition in atomic force microscopy (AFM) images of neural cells on nanofibrillar tissue scaffolds. Because the cellular edges and processes are on the same order as the background nanofibers, this imaging situation presents a feature definition problem. The diagnostic approach is based on analysis of discrete Fourier transforms of standard AFM section measurements. The diagnostic conclusion that the combination of dynamic range enhancement with low-frequency component suppression enhances feature definition is shown to be correct and to lead to clear-featured images that could change previously held assumptions about the cell–cell interactions present. Clear feature definition of cells on scaffolds extends the usefulness of AFM imaging for use in regenerative medicine. SCANNING 34: 316–324, 2012. © 2012 Wiley Periodicals, Inc.

Abstract: Summary The naturally occurring structure of articular cartilage has proven to be an effective means for the facilitation of motion and load support in equine and other animal joints Cartilage has been found to be a complex and dynamic medium, which has led to an incomplete understanding of the nature and operating mechanisms acting within a joint Although cartilage has biphasic and triphasic properties, it is believed that the performance of equine articular joints is influenced by the surface roughness of the joint cartilage (Ateshian et al, '98; Chan et al, 2011; Yao and Unsworth, '93) Various joint types with different motions and regimes of lubrication have altered demands on the articular surface that may affect cartilage surface properties In research performed on freshly harvested samples, equine articular cartilage has been shown to possess a multiscale structure and a fractal dimension It is thought that by determining the fractal dimension (D) of articular cartilage, a better understanding of the friction, wear, and lubrication mechanisms for biomechanic surfaces can eventually be reached This study looks at the fractal dimensions of three different articular cartilage surfaces in the equine carpus: the radiocarpal, midcarpal, and carpometacarpal surfaces The three surfaces provide an ideal comparison of fractal dimensions for a different range of motion, geometry, and loading In each sample, identical treatment was performed during measurement by a stylus profilometer SCANNING 34: 418–426, 2012 © 2012 Wiley Periodicals, Inc

Abstract: Since the way that human bone cells behave on contact with different surfaces topographies seems to be crucial to osseointegration, the aim of the present study is to evaluate the participation of some micro- and nanosized features of Ti surfaces in the short-term response of primary human osteoblast-like cells (HOC). Surfaces were prepared as ground (G-Ti), hydrofluoric acid etched (HF-Ti), and sandblasted/HF-etched (SLA-Ti), and analyzed using both three-dimensional (3D) profilometer and atomic force microscope (AFM). Cell morphology was assessed using scanning electron microscopy (SEM) after 4 and 24 h in culture. Cell viability, adhesion, and spreading were also evaluated 4 and 24 h after seeding over each surface. Data were compared by analysis of variance (ANOVA) complemented by Duncan test. Cell morphology, cell counting, and membrane integrity (Neutral Red, NR) were not affected by surface treatment at any time. However, HF-Ti presented the smallest surface area and did not increase tetrazolium hydroxide (XTT) reduction from 4 to 24 h. On the other hand, a higher level of spreading was only found on the rougher and isotropic SLA-Ti at 4 h. In conclusion, although all evaluated Ti surfaces allowed HOC short-term adhesion, the finer topography introduced by HF as single treatment did not favor HOC mitochondrial activity and spreading. The rougher and more complex SLA surface seems to provide a better substrate for HOC short-term response.

Abstract: This study proposes an innovative atomic force microscopy (AFM) based nanoscale electrical discharge machining (AFM-based nanoEDM) system which combines an AFM with a self-produced metallic probe and a high-voltage generator to create an atmospheric environment AFM-based nanoEDM system and a deionized water (DI water) environment AFM-based nanoEDM system. This study combines wire-cut processing and electrochemical tip sharpening techniques on a 40-µm thick stainless steel sheet to produce a high conductive AFM probes, the production can withstand high voltage and large current. The tip radius of these probes is approximately 40 nm. A probe test was executed on the AFM using probes to obtain nanoscales morphology of Si wafer surface. The silicon wafer was as a specimen to carry out AFM-base nanoEDM process in atmospheric and DI water environments by AFM-based nanoEDM system. After experiments, the results show that the atmospheric and DI water environment AFM-based nanoEDM systems operate smoothly. From experimental results, it can be found that the electric discharge depth of the silicon wafer at atmospheric environments is a mere 14.54 nm. In a DI water environment, the depth of electric discharge of the silicon wafer can reach 25.4 nm. This indicates that the EDM ability of DI water environment AFM-based nanoEDM system is higher than that of atmospheric environment AFM-based nanoEDM system. After multiple nanoEDM process, the tips become blunt. After applying electrochemical tip sharpening techniques, the tip radius can return to approximately 40 nm. Therefore, AFM probes produced in this study can be reused. SCANNING 34: 191–199, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: Assessment of skin lymphatic vessels is of great significance in understanding their roles in many pathological conditions. Our aim was to identify the optimal approach for investigation of cutaneous lymphatic system. We performed comparative studies on skin lymphatic vessels using immunohistochemistry of tissue sections, computer graphic reconstruction method together with immunohistochemically stained serial sections and whole mount fluorescence in human lower limb. Lymphatic vessels were identified with podoplanin antibody. The relative merits and drawbacks of each method in evaluation of structure, spatial organization, and distribution of cutaneous lymphatic vessels were described. Immunohistology of tissue sections enabled the investigation of the structure and distribution of the whole cutaneous lymphatic system in two-dimensional slices, whereas three-dimensional morphology of only the most superficial lymph capillary network immediately under the epidermis could be evaluated with the whole mount technique. Meanwhile, only little segmentation of skin lymphatic vessel from five immunohistochemically stained serial sections was reconstructed and evaluated due to expense and special skills required using computer graphic three-dimensional reconstruction. Furthermore, a great number of artifacts and special skills required in its processes leaded to less accurate structure of skin lymphatic vessels. Our findings demonstrated that the use of either of the proposed techniques alone could not allow a comprehensive analysis of the skin lymphatic system due to their relative drawbacks. Combination of immunohistology of tissue sections and three-dimensional whole-mount preparations appears to be the best candidate for comprehensive evaluation of skin lymphatic system.

Abstract: Gallium phosphide (GaP) surfaces were functionalized with two different molecules that contain an azide moiety at their terminus. Compound 4-azidophenacyl bromide (4AB) is an aryl azide with a bromine group at its opposite terminus that provides easy identification of the molecule's presence on the surface with x-ray photoelectron spectroscopy (XPS). O-(2-aminoethyl)-O'-(2-azidoethyl)pentaethylene glycol (AAP) is a small poly(ethylene glycol) molecule with an amine group at its opposite terminus. Atomic force microscopy was used to identify the uniformity of the clean and functionalized GaP surfaces. Water contact angle revealed a more hydrophobic surface with AAP functionalization (33°) and even more hydrophobic (53°) with the 4AB functionalized surface compared to a clean surface (16°). XPS confirmed the presence of each of the organic azides on the surface. XPS was further used to calculate the adlayer thickness of each functionalization. This analysis revealed an adlayer thickness of about 8 A for the 4AB functionalized surfaces compared to 1 A for the AAP adlayer, which led to the conclusion that AAP functionalization only provided partial coverage. A stability study using 4AB-functionalized surfaces showed good stability in saline solutions with varying concentrations of hydrogen peroxide. Finally, inductively coupled plasma mass spectrometry was used to evaluate the gallium concentration in the stability solutions. While the functionalization with the organic azides did not provide complete suppression of gallium leaching, both of the azides decreased the leaching by 10-50%.

Abstract: Mouse is an important animal model to investigate skin physiological and pathological states. In this article, multiphoton microscopic imaging of in vivo hair mouse skin based on two-photon excited fluorescence and second harmonic generation was examined. Our results show that multiphoton microscopy can clearly display microstructure of stratum corneum, stratum spinosum, and dermis of in vivo mouse skin. The main components of epidermis and dermis such as corneocytes, spinosum cell, collagen fibers, and hair follicles can be distinctly identified in MPM images. Using the optional HRZ 200fine focusing stage, thickness of different layers can be easily assessed. The results demonstrate that MPM can be regarded as an efficient method for in vivo investigation of skin physiological and pathological states by using hair mouse animal model. SCANNING 34: 170–173, 2012. © 2011 Wiley Periodicals, Inc.

Abstract: Summary Assembly of long single-stranded DNA (ssDNA) and short oligodeoxynucleotides onto bare highly oriented pyrolytic graphite (HOPG) at different temperature has been studied. It was indicated that both long ssDNA and oligodeoxynucleotides can sequentially form network, straight chains, and layer structures when the adsorption temperature was changed from room temperature, 37–55°C. High-resolution atomic force microscopy (AFM) imaging of the layer structures revealed that they are composed of parallel ssDNA chains with relatively higher height and tend to form patterns with three-fold symmetry. These new findings are significantly important for understanding assembly characterization of ssDNA. In addition, this assembly method for ssDNA is expected to be used for preparation of DNA structures in biosensing and DNA-based nanodevices. SCANNING 34: 302–308, 2012. © 2012 Wiley Periodicals, Inc.

Abstract: This study used atomic force microscopy (AFM), metallic probes with a nanoscale tip, and high-voltage generators to investigate the feasibility of high-voltage nano-oxidation processing in deionized water (DI water) and atmospheric environments. Researchers used a combination of wire-cutting and electrochemical etching to transform a 20-μm-thick stainless steel sheet into a conductive metallic AFM probe with a tip radius of 60 nm, capable of withstanding high voltages. The combination of AFM, high-voltage generators, and nanoscale metallic probes enabled nano-oxidation processing at 200 V in DI water environments, producing oxides up to 66.6 nm in height and 467.03 nm in width. Oxides produced through high-voltage nano-oxidation in atmospheric environments were 117.29 nm in height and 551.28 nm in width, considerably exceeding the dimensions of those produced in DI water. An increase in the applied bias voltage led to an apparent logarithmic increase in the height of the oxide dots in the range of 200-400 V. The performance of the proposed high-voltage nano-oxidation technique was relatively high with seamless integration between the AFM machine and the metallic probe fabricated in this study.

Abstract: Summary Young's modulus and electrical resistivity of individual titanium dioxide (TiO2) nanofibers were characterized using a nanomanipulator system installed in a focused ion beam-scanning electron microscope (FIB-SEM) dual-beam Scanning Electron Microscope system. Young's modulus of individual nanofibers was deduced from the analysis of their in situ resonance behavior in response to an oscillating electric field. The electrical behavior of a single nanofiber was also analyzed by a two-point method probed by a nanomanipulator. These results will contribute to the design of devices based on single TiO2 nanofibers, as well as devices based on nanofiber networks. The methods presented here can also be applied to characterize other one-dimensional nanostructures. SCANNING 34: 341–346, 2012. © 2012 Wiley Periodicals, Inc.

Abstract: Quality of an SEM image is strongly influenced by the extent of noise. As a well-known method in the field of SEM, the covariance is applied to measure the signal-to-noise ratio (SNR). This method has potential ability for highly accurate measurement of the SNR, which is hardly known until now. If the precautions discussed in this article are adopted, that method can demonstrate its real ability. These precautions are strongly related to "proper acquisition of two images with the identical view," "alignment of an aperture diaphragm," "reduction of charging phenomena," "elimination of particular noises," and "accurate focusing," As necessary, characteristics in SEM signal and noise are investigated from a few standpoints. When using the maximum performance of this measurement, SNR of many SEM images obtained in a variety of the SEM operating conditions and specimens can be measured accurately.

Abstract: This study investigates the surface conditions of silicon wafers with native oxide layers (NOL) or hydrogen passivated layers (HPL) and how they influence the processes of nano-oxidation and wet etching. We also explore the combination of nano-oxidation and wet etching processes to produce nanostructures. Experimental results reveal that the surface conditions of silicon wafers have a considerable impact on the results of nano-oxidation when combined with wet etching. The height and width of oxides on NOL samples exceeded the dimensions of oxides on HPL samples, and this difference became increasingly evident with an increase in applied bias voltage. The height of oxidized nanolines on the HPL sample increased after wet etching; however, the width of the lines increased only marginally. After wet etching, the height and width of oxides on the NOL were more than two times greater than those on the HPL. Increasing the applied bias voltage during nano-oxidation on NOL samples increased both the height and width of the oxides. After wet etching however, the increase in bias voltage appeared to have little effect on the height of oxidized nanolines, but the width of oxidized lines increased. This study also discovered that the use of higher applied bias voltages on NOL samples followed by wet etching results in nanostructures with a section profile closely resembling a curved surface. The use of this technique enabled researchers to create molds in the shape of a silicon nanolens array and an elegantly shaped nanoscale complex structures mold.

Abstract: Thermal stability of self-assembled monolayers (SAMs) is important for applications in various surface science applications. As a model material, 16-mercaptohexadecanoic acid (MHA) on template stripped gold surfaces was investigated to determine the effect of temperature on the change of lateral force signal using atomic force microscopy (AFM). Friction force signals were obtained at various temperatures in order to determine whether it was possible to correlate the friction signal with desorption of the thiol molecule from the surface. Samples were heated for up to 10 h ranging from 40 to 80°C in air and scanned every hour. A kinetic model was introduced to correlate the lateral force signal to the activation energy of desorption of the SAM from gold surface with heating. The activation energy of the detachment using this technique is 25.4 kcal/mol, which is consistent with other more complex techniques. SCANNING 34: 200–205, 2012. © 2011 Wiley Periodicals, Inc.