Search

The study aimed to develop and analyze bio-based composites, incorporating moringa bioresin and hemp fibers as reinforcing elements. The composites were fabricated using four weight percentage combinations of epoxy, moringa bioresin, and hemp fiber. The fabricated composites were characterized by their mechanical, thermal, water absorption, biodegradability, and morphological properties. The study revealed that the composite with the highest proportion of moringa bioresin (30 wt. %) exhibited better mechanical properties. Moreover, the flexural strength and Shore D hardness were impacted by both the matrix and reinforcing materials' weight percentages. Thermal analysis showed that the composites had good thermal stability, while water absorption analysis indicated that the composites had good water resistance. Biodegradability analysis showed that the composites had a high rate of biodegradation, making them environmentally friendly. The distribution of reinforcing fibers within the matrix material was found to be uniform through the use of scanning electron microscope based morphological analysis. The results indicate that moringa bioresin and hemp fiber composites have the potential to be used as sustainable alternatives to petroleum-based composites in various applications. [ABSTRACT FROM AUTHOR]

It has recently been demonstrated that electron beam injection into p-type β-gallium oxide leads to a significant linear increase in minority carrier diffusion length with injection duration, followed by its saturation. The effect was ascribed to trapping of non-equilibrium electrons (generated by a primary electron beam) at meta-stable native defect levels in the material, which in turn blocks recombination through these levels. In this work, in contrast to previous studies, the effect of electron injection in p-type Ga2O3 was investigated using cathodoluminescence technique in situ in scanning electron microscope, thus providing insight into minority carrier lifetime behavior under electron beam irradiation. The activation energy of ∼0.3 eV, obtained for the phenomenon of interest, is consistent with the involvement of Ga vacancy-related defects. [ABSTRACT FROM AUTHOR]

A pure nickel film and a carbon/nickel (C/Ni) composite film were produced using radio frequency magnetron sputtering. The structure of the films was regulated by adjusting the sputtering power and the time allocation of sputtering nickel and graphite targets. Furthermore, a scanning electron microscope, an x-ray diffractometer, and a Raman spectrometer were employed for sample characterization. The results demonstrated that the thickness of the pure nickel film and C/Ni composite film with a total deposition time of 60 s was between 44.96 and 65.31 nm. The nickel film exhibited preferential growth along the crystal plane (111), and the structure of carbon materials was in the second stage of the three-stage model known as "amorphization trajectory of graphite." The prepared films' electromagnetic interference shielding effectiveness (EMI SE) in the X-band was investigated using a vector network analyzer. It was observed that the C/Ni composite film with a thickness of 44.96 nm demonstrated a superior EMI SE with a maximum value reaching 21 dB. The EMI SE of the C/Ni composite film can reach the same performance and even exceed that of the pure nickel film obtained at the power of 200 W for 60 s in certain frequency segments. In conclusion, the pure nickel film can be replaced by C/Ni composite film prospectively due to their excellent EMI SE along with advantages such as reduced thickness, lighter weight, and lower cost. [ABSTRACT FROM AUTHOR]

We investigated electron emission characteristics of a hafnium carbide [HfC(100)] single-crystal tip at various temperatures toward finding a candidate of the next generation of emitters for electron microscopes. The emission mode changed from cold-field emission (CFE) to low-temperature and high-temperature thermal-field emission and, finally, to extended Schottky emission. The energy width at full width of half maximum of the emitted electrons was 0.2 eV in the CFE mode at an angular current of 20 μA/sr, and it showed good emission stability with current noise less than 3.5% in an electron gun of a scanning electron microscope (SEM). Spatial resolution of the SEM at an acceleration voltage of 0.5 kV improved 14% by using the HfC(100)-CFE tip instead of a conventional W(310)-CFE tip. High monochromaticity and stable electron emission of the HfC(100)-CFE tip are suitable for the next generation of emitters for ultrahigh-resolution field emission SEMs. [ABSTRACT FROM AUTHOR]

Magnesium AZ91/AlN-based surface composites have been synthesized using the friction stir processing (FSP) technique. The influence of particle addition during FSP on microstructural and mechanical properties has been investigated. Composite plates of 5, 10, and 15 vol. % AlN were synthesized using two-pass FSP with an axial force of 10 KN, a tool travel speed of 40 mm/min, and a tool rotation speed of 1200 rpm. The AZ91/AlN surface composites were analyzed microscopically with the use of an optical microscope, an x-ray diffractometer, and a scanning electron microscope. The prepared composites were tested for hardness and tensile strength. Micrographs taken in the stir zone revealed a consistent distribution of AlN particles throughout the AZ91 matrix. The AZ91/AlN surface composites were tested for hardness and tensile strength, and the findings showed that the AlN particles improved the mechanical properties without significantly decreasing ductility. The fracture surfaces of the composites were studied, and the mechanisms of fracture were identified. [ABSTRACT FROM AUTHOR]

Body fluids can potentially indicate the presence of non-small cancer cells. Studying these fluids is an emerging field that could be crucial for cancer detection and monitoring treatment effectiveness. Meanwhile, the examination of fluids on a microscopic level is part of the field of microfluidics. This study focuses on the development of a total analysis system that consists of various interconnected structures that are designed to mix, classify, concentrate, and isolate particles in fluids that mimic the behavior of cancer and normal cells. Using the COMSOL Multiphysics software, the device's performance was optimized to use a pressure input of 35 kPa for water or serum and 29.4 kPa for a mixture of liquid and serum samples, which are the optimal pressure inputs. The numerical models were validated by experiments using two types of polystyrene particles, with diameters of 5 and 20 μm. Moreover, the developed system was applied to monitor the behavior of red blood cells. The microfluidic chip is capable of addressing several challenges through visual detections, including mixing tests of two fluids with similar densities, proper particle size classification using Dean flow fractionation, and single-step recovery of large, labeled particles. Finally, the collected particles were examined using an environmental scanning electron microscope to determine their size, and the results demonstrated that successful size separation was achieved, with particles around 20 μm completely separated from the smaller ones. [ABSTRACT FROM AUTHOR]

Single zinc oxide nanowires (ZnO NWs) are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties, but characterizing the latter efficiently is challenging. As reported here, an electrical breakdown strategy was used to construct single ZnO NWs with a specific length. With the high operability of a nanomanipulator in a scanning electron microscope, ZnO-NW-based two-probe and three-probe structures were constructed for fabricating AC/DC nanogenerators, respectively. For a ZnO NW, an AC output of between −15.31 mV and 5.82 mV was achieved, while for a DC nanogenerator, an output of ∼24.3 mV was realized. Also, the three-probe structure's output method was changed to verify the distribution of piezoelectric charges when a single ZnO NW is bent by a probe, and DC outputs of different amplitudes were achieved. This study provides a low-cost, highly convenient, and operational method for studying the AC/DC output characteristics of single NWs, which is beneficial for the further development of nanogenerators. ARTICLE HIGHLIGHTS: HIGHLIGHTS • A method for reworking NWs to a specific length was achieved using an electrical breakdown strategy based on the constructed electrical loop, and its success rate is high. • With the maneuverability provided by multiple operating units of a nanomanipulator, AC output was investigated for a single ZnO NW with a two-probe structure, as well as DC output with a three-probe structure. • In the three-probe structure, different DC outputs were achieved by changing the position of the NW–probe contact point and the wiring state of the probe, while the distribution of surface piezoelectric potential along the NW's axis was studied. [ABSTRACT FROM AUTHOR]

The primary goal of this study is to examine the impact of sodium hydroxide (NaOH)/alkali-activated fly ash on the fresh properties and mechanical properties of self-compacting concrete (SCC). The fresh properties, known as the workability of SCC characteristics, were determined using the U-box, V-funnel, J-ring, and L-box tests. The M30 grade SCC containing superplasticizer of 0.86 wt. % of cement is replaced with 10%, 15%, 20%, 25%, 30%, and 40% of alkali-activated fly ash. On days 7, 14, and 28 after curing, the compressive strength and the splitting tensile strength of the SCC were examined. The study was further extended to evaluate the behavior of reinforced concrete beams containing fly ash and ground granulated blast furnace slag, whose size was 1200 × 100 × 150 mm3, under flexure loading. Based on the test results, it was found that the increase in the replacement of cement with alkali-activated fly ash increased the workability in the SCC. With the addition of superplasticizers, the SCC gained much more workability than conventional concrete containing no superplasticizer. The mechanical properties of 10% and 15% activated fly ash in Portland cement provided the maximum strength for the SCC at different ages of curing. The maximum first crack load and maximum ultimate flexure loading of the reinforced concrete beam containing 10% activated fly ash by weight of cement were greater than those of the control concrete beam. The microstructural scanning electron microscope observations confirmed that the alkali-activated fly ash increased the strength properties of the self-compacting concrete. [ABSTRACT FROM AUTHOR]

The use of aluminum alloys in automobiles is expanding, and the potential for additional increases is significant. Further growth will be determined by improvements in material qualities for existing applications or the discovery of new applications. Alloy A-356 (LM25) is commonly employed for high-quality alloy wheel rims in various motor vehicles, constituting 40% of global car usage. This study introduces 0.2% Cu into the Al–Si–Mg alloy system to enhance the mechanical properties. The alloy blend is cast into a metal mold, subjected to a 4-h cure at 540 °C, quenched with water, and precipitation hardened for 12 h at 1800 °C. Optical and scanning electron microscopes are utilized to analyze the alkali microstructure. The mechanical properties of alloyed and unalloyed castings, including hardness and tensile test results, are examined in untreated and heat-treated states. Fracture surfaces of tensile specimens are scrutinized. Intermetallic compounds formed during solidification are studied using scanning electron microscopy and x-ray diffraction analysis. The tensile strength under unalloyed (LM25) and alloyed (LM25 + 0.2 wt. % Cu) conditions before and after heat treatment [(72, 165.4 and 88.3, 237.1) and (78, 179.6 and 98, 252.9, respectively)] shows a significant increase. [ABSTRACT FROM AUTHOR]

Integrating carbon nanotubes (CNTs) into a polymer matrix can significantly modify its physical properties, providing that the challenges associated with CNT dispersion are successfully resolved. In this work, we investigate the enhancement of the dielectric properties of silicone when multiwall carbon nanotubes (MWCNTs) are introduced to its polymer matrix as a filler in the frequency range from 0.5 to 20 GHz. An optimized procedure is used to prepare nanocomposites with MWCNTs concentrations by weight of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. The investigated dielectric properties for the prepared nanocomposites are the real dielectric constant ɛ′, the imaginary dielectric constant ɛ″, the loss tangent tan δ, and the AC conductivity σAC. The dispersion of the MWCNTs in the silicone matrix is confirmed using the Fourier-transform infrared (FTIR) spectroscopy and the scanning electron microscope. This study shows that the dielectric properties of the nanocomposite are enhanced as the MWCNT's concentration is increased over the entire frequency range. For example, the enhancement in ɛ′ value was from 3.2 up to 21.6 at 0.5 GHz and from 2.5 to 10.6 at 20 GHz as the concentration increased from 0% to 2.0%. For the ɛ″ value, the enhancement was from less than 0.1 to 8.6 at 0.5 GHz and to 2.0 at 20 GHz, respectively. Based on the obtained tanδ values, the nanocomposites with MWCNTs of 0.5% and 1.0% can be classified as low-loss dielectrics, while the other nanocomposites with MWCNTs of 1.5% and 2.0% are classified as lossy dielectrics. [ABSTRACT FROM AUTHOR]

The damage impact of mechanical shocks on stator bar insulation is a key factor in high-voltage motor accidents. This study conducted electrical aging acceleration and breakdown experiments on damaged stator insulating materials to understand failure causes and evaluation methods. The relationship between sample defect area and depth and electrical properties was analyzed, along with the morphology of the damaged surface using a scanning electron microscope. Results show that the defect area correlates with impact mode but does not directly impact electrical performance. Effective insulation thickness is positively linked to electrical performance. This study serves as a valuable reference for evaluating mechanical impact faults in high-voltage motors. [ABSTRACT FROM AUTHOR]

By applying ultrasonic treatment to ZL205A aluminum alloy melt containing different Cd contents and then using a tensile test, a scanning electron microscope experiment, and a metallographic experiment, the influence of ultrasonic treatment to ZL205A aluminum alloy melt on the properties of aluminum–copper alloy with different Cd contents in the liquid phase high-temperature region was studied. The effect of ultrasonic treatment on the solidification structure of ZL205A aluminum alloy was investigated. The results showed that there was no significant difference in the form of Cd and the solid solution rate of the aluminum alloy with different Cd contents in ultrasonic-assisted casting. However, the effect of ultrasonic waves on the high-temperature liquid phase of the melt of ZL205A aluminum alloy can effectively reduce the porosity defects in the solidification structure of the casting, refine the solidification structure, and make the structure more uniform. The ultrasonic cavitation effect can promote the formation and uniform distribution of Al–3Ti and improve the nucleation rate, and the effect can continue after heat treatment. This can solve the problem that increasing Cd content in ZL205A greatly reduces the toughness of castings while increasing the strength. The sample with a Cd content of 0.20% and with ultrasonic treatment has the highest strength, the average tensile strength is 475.5 MPa, and the yield strength is 381.75 MPa. However, compared with the conventional casting samples with the same Cd content, the decrease in elongation was significantly reduced. [ABSTRACT FROM AUTHOR]

The changes in mechanical properties of glass fiber reinforced plastic cross-ply laminates as a result of hydrothermal aging were studied theoretically. The composite specimens have been immersed in distilled water at 25, 40, and 70 °C for 60 days for aging testing. Based on Fick's law and the Arrhenius theorem, the moisture absorption data under different environments was analyzed, and the method for determining the diffusivity and the equilibrium moisture content was obtained. The relationship model between the moisture absorption behavior of the composite material and the ambient temperature was proposed and verified by finite element analysis. The mechanical behavior of the composites was studied by tensile, compression, and three-point bending tests. Under the condition of ultimate moisture absorption, the tensile, compressive, and bending strengths of the composite decreased by 31.663%, 12.948%, and 26.985%, respectively. A variety of empirical models were used for data analysis, which confirmed the strong correlation between strength degradation and moisture absorption of composite cross-ply laminates. The scanning electron microscope observation results of different moisture absorption levels showed that matrix cracking and fiber/matrix interface debonding caused by moisture absorption are the fundamental reasons for the strength degradation of the composites. [ABSTRACT FROM AUTHOR]

With this experimental study, ZrO2/B4C/Al2O3/SiC ceramics in different weight ratios were added to 99.5% pure aluminum and composites were produced by vacuum infiltration, which is very rare in the literature. It is aimed to investigate how different ceramics will affect the technical properties of an aluminum composite. First, scanning electron microscope images were taken to examine their microstructures, and energy-dispersive x-ray spectroscopy analyses were performed. In addition, x-ray diffraction analyses of phase structures were performed. Then, the densities of the composite structures were measured. In the last stage of the experiments, hardness measurement, bending strength, and abrasive wear amount tests were carried out to determine the mechanical properties of the composite structures. According to the data obtained, a relatively homogeneous structure was obtained up to 10% of the ceramic particles in the structure. It was observed that thermal damage did not occur in the composite structures and no significant phase changes occurred. The highest infiltration distance was obtained from B4C-reinforced samples, and the lowest infiltration distances were obtained from ZrO2-reinforced samples. Ceramic reinforcement elements have reduced the density values of composite structures. With the increase in the ratio of ceramic reinforcement particles, the hardness values of the composites increased and the flexural strength values decreased. In the abrasive wear tests, the least wear loss was obtained from SiC-reinforced samples and the highest wear loss was obtained from ZrO2-reinforced samples. When the composites were evaluated according to their microstructure and mechanical strength, the best results were obtained with SiC and then Al2O3, B4C, and ZrO2 reinforcements, respectively. It has been concluded that SiC, Al2O3, B4C, and ZrO2 reinforcement elements in Al 1050-based composites produced by vacuum infiltration have a positive effect on most of the mechanical properties and a negative effect on some of them. [ABSTRACT FROM AUTHOR]

Near-stoichiometric chromium diboride films were subject to in situ annealing inside a scanning transmission electron microscope to access the thermal behavior of the film and embedded structural planar defects. Independent of films' stoichiometry, the planar defects were unaffected by the applied heat treatments. On the contrary, the interfaces between the boron-rich tissue phase and the CrB2 phase were reshaped in the overstoichometric CrB2 film. At high temperatures, diffusion of contact metal species (platinum) from the focused ion beam sample preparation was triggered, with subsequent migration onto the sample. This resulted in the formation of metal-rich regions as directly observed and characterized at the atomic level. We determined that platinum did not react with the diboride structure but is accommodated by various defects present in the film. [ABSTRACT FROM AUTHOR]

In this study, basalt fibers (BFs) and nano-silica (NS) were innovatively combined to reinforce recycled aggregate concrete (RAC) to prepare recycled aggregate concrete (named NBRAC) with better mechanical and microstructural properties as an alternative to ordinary concrete. Different NBRAC specimens were prepared by adjusting the contents of NS and BF; the damage mechanism and mechanical properties of NBRAC were investigated; and the compressive, split tensile, and flexural strengths of NBRAC were evaluated. The microstructure of NBRAC was analyzed by scanning electron microscopy observation. The results showed that the densification of NBRAC was improved under the condition of 50% RA substitution rate and that its compressive, split tensile, and flexural strengths were increased by 6.8%, 16.3%, and 32.7%, respectively, compared with that of natural concrete, which proved that the method was feasible for the preparation of high-performance RAC. Scanning electron microscope image analysis confirmed the improvement effects of NS and BF on RAC, and combined with the experimental data, a composite explanation for the improvement effects of NS and BF on RAC was proposed for the first time. [ABSTRACT FROM AUTHOR]

The use of slag-based alkali-activated concrete (AAC) could effectively address the issues of resource extraction and carbon emissions caused by traditional Portland cement. In this study, the effects of the fly ash content, water–binder ratio, and alkali activation modulus on the early mechanical properties of AAC were investigated. A total of 105 cube specimens (35 sets) were designed and subjected to compressive strength tests, scanning electron microscope tests, and x-ray diffraction composition analysis. The results indicated that excellent early strength was observed in AAC, with a compressive strength reaching ∼90% of the 28th day strength before 14 days. An increase in the fly ash content and a decrease in the water–binder ratio significantly improved the compressive strength within the same age period. The impact of a lower alkaline activation modulus on strength was found to be insignificant. Based on the experimental results, a calculation method and a constitutive model for early strength were proposed, and the theoretical values exhibited a high level of agreement with the measured values. [ABSTRACT FROM AUTHOR]

The operando hydrogen microscope is an original apparatus that has been developed to visualize the time-dependent permeation of hydrogen through a sample. This apparatus is developed based on an ultrahigh vacuum scanning electron microscope (UHV SEM). The system consists of a lens system to focus ions produced by electron-stimulated desorption (ESD), an ion detector optimized for ESD-signal detection, and a two-dimensional measurement program synchronized with the position information of the electron beam. The developed detectors and electrostatic lenses enable highly sensitive detection of the ions. In this paper, we show the details of the instrumentation of the operando hydrogen microscope. We have succeeded in recording hydrogen and deuterium flowing from the rear of metals to the surface as a series of time-lapse images, showing the time-dependent changes in the surface distribution of hydrogen and deuterium. Deuterium permeation through the metal sample was dynamically visualized at the surface by the two-dimensional mapping of the desorbed ions induced by scanning electron beam irradiation. [ABSTRACT FROM AUTHOR]

Using a scanning electron microscope, we irradiate graphene drums with electrons at an energy of 20 keV and a dosage of about 1.58 × 1017 electrons/cm2. The drums consist of graphene exfoliated in ambient air over holes having a diameter of 4.6 μm and etched into an SiO2 substrate. After irradiation, we observe that the drum's suspended monolayer (ML) region has a ratio of the Raman D peak height, ID, to the Raman G peak height, IG, as high as 6.3. In contrast, the supported ML on the SiO2 substrate has an ID/IG ratio of 0.49. Previous studies have shown that graphene drums containing air can leak in a vacuum at a low rate. We attribute the high ID/IG ratio of the suspended ML to the air that may be in the drums. We propose that the air produces much adsorbed water on the ML, resulting in a high average defect density during irradiation. We present Raman maps of the full-width-at-half maximum, position, and height of the G, 2D, D, and D' peaks before and after irradiation and maps of ID/IG and ID/ID'. We anneal the drums at temperatures from 50 to 215 °C and find that ID/IG significantly reduces to 0.42. The annealing data are analyzed using an Arrhenius plot. We also find that ID/ID' depends on annealing temperature and has values ≥8, in the range expected for sp3 defects, for ID/IG ≤ 3.9. This irradiation method may help achieve high average defect densities in ML graphene, imparting novel and potentially valuable properties. [ABSTRACT FROM AUTHOR]

Lithium batteries are promising techniques for renewable energy storage attributing to their excellent cycle performance, relatively low cost, and guaranteed safety performance. The performance of the LiFePO4 (LFP) battery directly determines the stability and safety of energy storage power station operation, and the properties of the internal electrode materials are the core and key to determine the quality of the battery. In this work, two kinds of commercial LFP batteries were studied by analyzing the electrical properties and material properties of the electrodes. After performing the rate and cycle performance tests of the battery cell, differential scanning calorimetry, scanning electron microscope, x-ray diffraction, and inductively coupled plasma were used to explore the performance of electrode materials to establish the correlation between the battery performance and the electrochemical reaction law of the internal materials and further to judge the influence of the key material properties on the battery performance. This work opens up an avenue for technical supervision of energy storage power stations. [ABSTRACT FROM AUTHOR]

To address the challenges of accurate metrology of height and sidewall angle (SWA) of three-dimensional structures with critical dimension scanning electron microscopy, general modeling and algorithms based on tilted electron beam technology and the corresponding application skills are proposed, and the validity and error accuracy are evaluated as well. Three typical structures, the trapezoid, inverted trapezoid, and step, are investigated with Monte Carlo simulation. The maximum derivative method is used to extract key parameters from the secondary electron linescan. The efficiency of the proposed modeling, algorithms, and the accuracy of the calculated height and SWA are improved further with the application of wavelet transform. [ABSTRACT FROM AUTHOR]

Lateral field emission devices have been characterized before and after ultraviolet (UV) light exposure. Two types of planar device structures, diode and bowtie, were studied. These nanoscale devices have 9–15 nm tip-to-tip (bowtie) or tip-to-collector (diode) dimensions with the tips fabricated from Au/Ti. Typical currents of 2–5 nA per tip at 6 V were measured. It was observed that after UV exposure, the collected current was reduced by >28% for the case of a bowtie device; whereas the current was reduced by >39% for the case of a diode device. This reduction can be attributed to water vapor desorption on the dielectric surface between the structures, which in turn reduces surface leakage. The Fowler–Nordheim plot showed a straighter line after UV exposure. After the I-V test, the UV-exposed devices were placed on lifetime tests in a vacuum of <10−8 Torr and were biased at 5 V DC. After 2600 h, an abrupt current decrease was observed: ∼25% for the case of the bowtie and ∼28% for the case of the diode device. Scanning electron microscope images of the bowtie and diode devices showed damage to the tips. [ABSTRACT FROM AUTHOR]

This paper describes the influence of vacuum annealing on the mechanical characteristics of silicon (Si) nanowires (NWs) fabricated using focused ion beam (FIB) technologies. Two types of Si NWs having a cross-sectional one-side length or diameter ranging from 19 to 447 nm are prepared using the direct milling and Ga ion doping functions of FIB. The Si NWs prepared are annealed at 400–700 °C in high vacuum for 10 min, followed by quasi-static uniaxial tensile testing using a microelectromechanical system based tensile test system in a scanning electron microscope. All the Si NWs fracture in a brittle manner. Young's modulus of submicrometer-sized Si NWs shows both annealing and specimen size influences in the range from 120 to 170 GPa, whereas that of nano-sized Si NWs shows only annealing influence in the range from 60 to 110 GPa. Tensile strength scatters greatly, ranging from 1.0 to 7.2 GPa, which increases with increasing the NW size. A transmission electron microscope and an atomic force microscope suggest that, by annealing, recrystallization happens in the damaged layer introduced by FIB milling and the NW surface morphology changes due to its recrystallization and gallium (Ga) ion evaporation. Fracture origin is discussed through the comparison between surface roughness and crack length estimated by the Griffith theory of brittle fracture. [ABSTRACT FROM AUTHOR]

Dust-mitigating surfaces typically consist of high-aspect-ratio structures that separate particles from resting on the bulk material, thereby limiting adhesion due to short-range van der Waals forces. These surfaces can find uses in solar-panel coatings and a variety of dust-resistant optics. The current method for quantifying surface contamination is optical microscopy, but this method is inadequate for observing particles at the submicrometer scale due to the diffraction limit. Furthermore, regardless of the microscopy technique, particle identification becomes problematic as the particle contaminates approach the same length scale of the surface structures. In this work, we demonstrate a method to identify micro-/nanoparticle contaminates on nanostructured surfaces using electron microscopy and image processing. This approach allows the characterization of particles that approach the length scale of the surface structures. Image processing, including spectrum filters and edge detection, is used to remove the periodic features of the surface nanostructure to omit them from the particle counting. The detection of these small particles using electron microscopy leads to an average of 5.62 particles/100 μm2 detected compared to 0.63 particles/100 μm2 detected for the traditional confocal optical detection method. Beyond dust-mitigation nanostructures, the demonstrated particle detection technique can find applications in nanobiology, the detection of ice nucleation on a structured surface, and semiconductor mask inspections. [ABSTRACT FROM AUTHOR]

Plasma etching effects, such as microtrenching and bowing, negatively impact device performance. Modeling of these effects at nanoscale is challenging, and theoretical and experimental investigations are highly desired to gain insights into mechanisms. In this paper, we propose a new plasma etching model based on Monte Carlo simulations with a cellular method. This model considers reactions and ion-enhanced etching and consists of a novel particle reflection algorithm, which is a key factor impacting the etch profile. This model reproduces the adjustable microtrenching and bowing effects in periodic dense trenches with tens of nanometer dimensions. We conduct experiments of Si etching by Cl 2 and validate the model by comparing the simulated profile with cross-sectional scanning electron microscope images. This work enables a potential physical model driven process emulation tool toward design technology co-optimization. [ABSTRACT FROM AUTHOR]

To study the effect of aging on the low-temperature crack resistance of fiber asphalt mixes, three kinds of fibers (lignin fiber, polyester fiber, and basalt fiber) were dry blended into AC-13 asphalt mixes to prepare unaged, asphalt aged (that is, the original asphalt material is subjected to aging treatment), short-term aged, and long-term aged fiber reinforced asphalt mixes. Semicircular bending (SCB) tests and scanning electron microscopy tests were used to analyze and study the effects of aging time and fiber type on the low-temperature properties of asphalt mixtures at an ambient temperature of −5 °C. The SCB test results indicated that: with the deepening of aging, the fracture toughness and fracture energy of the fiber asphalt mixture specimens will tend to decrease, and the aging of the original asphalt has a greater impact on the specimens without fiber; there was great variability in the effect of lignin fibers on the crack resistance of the mix, but it could be a good promoter in unaged asphalt mixes; polyester fiber is the material of choice for improving low-temperature crack resistance in long-term aging pavements; the incorporation of basalt fiber greatly enhances the crack resistance of asphalt mixes and is an excellent material for improving aging asphalt mixes. It is clearly seen by the scanning electron microscope test that with the deepening of aging, the adhesion of asphalt and aggregate gradually deteriorates, and even more so, there is the phenomenon of fine aggregate flaking, and the fiber cannot play an excellent role in reinforcement and crack resistance. [ABSTRACT FROM AUTHOR]

Femtosecond laser ablation has found wide-ranging applications in the surface structuring of nanoelectronics and nanophotonics devices. Traditionally, the inspection of the fabricated three-dimensional (3D) morphology was performed using a scanning electron microscope or atomic force microscopy in an ex situ manner after processing was complete. To quickly monitor and efficiently optimize the quality of surface fabrication, we developed an in situ method to accurately reconstruct the 3D morphology of surface micro-structures. This method is based on a triangulation optical system that utilizes structured illumination. The approach offers a super-resolution capacity, making it a powerful and non-invasive tool for quick in situ monitoring of surface ablation structures. [ABSTRACT FROM AUTHOR]

Electric Field Assisted Sintering (EFAS, also referred to as spark plasma sintering) is a powerful technology for the consolidation of powder materials. The high heating rate during the sintering process is critical for minimizing energy consumption, but it can also cause microstructure heterogeneities in sintered parts, such as spatially varied porosity. The examination of localized porosity usually requires the use of a scanning electron microscope with a carefully prepared surface. In this paper, photothermal radiometry is used to measure local thermal diffusivity and extract localized porosity of EFAS-sintered parts by using a percolation-threshold model. Applying this approach, we identified the radial position-dependent porosity variation in EFAS parts, which is likely formed due to the large temperature gradient during the sintering process. This approach has a unique advantage because it can measure samples with minimal or no surface preparation, enabling the possibility of in situ characterization in EFAS with proper system modification. Necessary modifications on the measurement approach for EFAS deployment and in situ characterization are also discussed. [ABSTRACT FROM AUTHOR]

Malignant central airway obstruction (MCAO) resulting from tumor metastasis and compression severely impairs respiration, posing life-threatening risks. To address this, we employed a synergistic modification strategy, combining cisplatin (CIS) and silver nanoparticles (AgNPs). Polycaprolactone (PCL) served as a drug carrier, enabling the preparation of a functional CIS@AgNPs@PCL fiber membrane-covered airway stent via electrospinning. This approach aimed to enhance the patency rate of MCAO. Characterization via ATR-FTIR, scanning electron microscope-energy-dispersive spectroscopy, and transmission electron microscope confirmed successful immobilization of CIS and AgNPs onto the stent surface. CIS@AgNPs@PCL substantially suppressed non-small cell lung cancer cells (A549), causing DNA damage, ultrastructural disruption, and over 50% apoptosis in 48 h. It also displayed potent antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans biofilms. A mouse subcutaneous tumor recurrence model assessed anti-cancer efficacy. CIS@AgNPs@PCL fiber-covered stents significantly inhibited lung cancer tissue and enhanced anti-cancer effects by up-regulating caspase-3 and Bax, while down-regulating Bcl-2. This study's functional airway stent provides a proof-of-concept for an integrated anti-cancer and antibacterial strategy. It promptly restores the lumen, inhibits biofilm formation, prevents tumor progression, and improves postoperative MCAO patency. [ABSTRACT FROM AUTHOR]

Scanning electron microscope is not only a versatile visualization and characterization tool for nanomaterials, but it is also widely used for visual feedback during assembly and manipulation of micro- and nanoparticles, novel devices based on 2D and 1D materials, and microrobots. Due to increase in the surface-to-volume ratio, adhesion forces play a significant role in micro- and nanorobotic applications. We investigate the quantitative effect of electron beam irradiation on nanoscale adhesive interactions between different end effector types and plain substrates. For this purpose, we use an interferometry-based force measurement setup integrated into the chamber of a scanning electron microscope capable of a subnano Newton force resolution. We provide quantitative results for the influence of the electron beam on the adhesion forces depending on the exposure dose, geometrical configuration in which it is applied, as well as on the material of the end effector. Simulation results, atomic force microscope adhesion measurements, and measurements with piezoresistive cantilevers serve as references. Our findings indicate that the electron beam influences the adhesive interaction not only in the case of insulating probes but also for well-grounded conducting and semiconducting probes. Its influence can range from several 10% to several 100% in comparison to the adhesion values measured with an atomic force microscope in an ambient atmosphere and no charged particle beam is applied. Moreover, it is shown that the influence of a charged particle beam is a multidimensional phenomenon that depends on several factors such as end effector and substrate material, geometry and aspect ratio of the end effector, geometrical configuration between particle beam and probe–sample arrangement, as well as exposure dose and field of view. We provide recommendations for handling and characterization of micro- and nano-objects using end effectors under the influence of charged particle beams: not to rely on adhesion values acquired in different environmental and exposure conditions, not to expect the application of conductive materials and grounding to completely avoid the effect of charged particle beams, and to be aware that charged particle beams can lower or increase the adhesion force in vacuum depending on material properties, among others. [ABSTRACT FROM AUTHOR]

The critical dimensions of advanced semiconductor manufacturing processes have decreased to a few tens of nanometers while the aspect ratios have increased beyond 100. The performance of plasma etch patterning processes as well as the cost and time of the development cycle are critical to the success of ramping a new technology node toward profitable high-volume manufacturing. In this paper, a computational patterning software, ProETCH®, has been developed with rigorous physics and advanced algorithms for modeling the etch patterning process, with the featured capabilities in calibrating the reaction mechanisms and optimizing the etch process. A shallow trench isolation etch process using self-aligned double patterning was investigated. A reaction mechanism of silicon etch by Ar/Cl2 plasma was developed to address the surface reactions, and a plasma hypermodel was introduced to correlate process operating conditions to plasma parameters at the wafer surface. The parameters of the reaction mechanism and the plasma hypermodel were calibrated with experimental data obtained from cross-sectional scanning electron microscope (XSEM) images. The calibrated model is used to identify the different fundamental pathways that contribute to the observed profile metrics in XSEMs. The model was then used for process development and optimization by solving the forward and inverse problems. In the forward problem, the model is used to predict the etching profile at different process conditions. Predictions for both interpolation conditions (process parameters within the range used for developing the model) and extrapolation conditions (process parameters outside of the range used for developing the model) agree well with the experimental data with the root mean square error less than 4 nm (1 nm resolution used for the mesh). In the inverse problem, the developed model is used to search for process conditions (e.g., values of bias power and pressure), which could result in desirable profiles. The solutions to the inverse problem demonstrate a degeneracy in process space of the etching process for a given target profile. [ABSTRACT FROM AUTHOR]

Single photon emitters in solid-state crystals have received a lot of attention as building blocks for numerous quantum technology applications. Fluorescent defects in hexagonal boron nitride (hBN) stand out due to their high luminosity and robust operation at room temperature. The fabrication of identical emitters at pre-defined sites is still challenging, which hampers the integration of these defects in optical systems and electro-optical devices. Here, we demonstrate the localized fabrication of hBN emitter arrays by electron beam irradiation using a standard scanning electron microscope with deep sub-micron lateral precision. The emitters are created with a high yield and a reproducible spectrum peaking at 575 nm. Our measurements of optically detected magnetic resonance have not revealed any addressable spin states. Using density functional theory, we attribute the experimentally observed emission lines to carbon-related defects, which are activated by the electron beam. Our scalable approach provides a promising pathway for fabricating room temperature single photon emitters in integrated quantum devices. [ABSTRACT FROM AUTHOR]

A microheater with a small temperature coefficient of resistance (TCR) at liquid hydrogen temperature was designed and fabricated by microfabrication technology. The NiCr heater annealed in N2 at 250 °C achieved the smallest TCR. The crystal structures of the NiCr film annealed in nitrogen were analyzed using a scanning electron microscope (SEM) and by x-ray diffraction (XRD). The crystallization of the NiCr film improved with the increase in annealing temperature. The failure mechanism of the microheater is studied, and it is seen that the central area of the heating film and the joint of the heating film and the electrode are most vulnerable to destruction. [ABSTRACT FROM AUTHOR]

TiN coatings were in situ deposited on un-nitrided and nitrided M2 high speed steels by electrically enhanced cathodic arc evaporation technology. The morphology, microstructure, phase composition, as well as microhardness and nano-hardness of the samples were analyzed by scanning electron microscope, optical microscope, X-ray diffraction, Vickers hardness tester, and nano-indentation, respectively. In especially, the effect of nitriding substrate current density on the adhesion strength of in situ TiN coatings was investigated by Rockwell indentation and scratch tests. The results showed that the nitrided layer thickness increased with increasing substrate current density and "bright" nitrided layer was achieved. In the Rockwell indentation test, the radial cracks on the surface of the duplex-treated samples originated from the hard and brittle nitrided layer as compared to the nitrided substrate, which corresponded to the failure mechanism of brittle fracture. In the scratch test, the adhesion strength of coating to substrates was significantly improved by nitriding pretreatment. Furthermore, the critical load of the duplex-treated samples increased with the increase of nitriding substrate current density. In addition, tensile cracks only occurred in the case of the N120/TiN sample. [ABSTRACT FROM AUTHOR]

The tribological properties of metal-CuS/MoS2 composite coatings were improved by selecting the metal materials and optimizing the heat treatment process. The composite coatings were prepared by magnetron cosputtering of copper or aluminum metals, CuS, and MoS2. Then, the prepared Cu-CuS/MoS2 and Al-CuS/MoS2 were subjected to vacuum heat treatment at 220, 320, and 420 °C. The structure and tribological properties of the composite coatings were analyzed by scanning electron microscope, energy spectrum, x-ray diffraction, Raman spectrum, and multifunction friction tester. The results showed an island-like growth and a dense noncylindrical cross-sectional morphology of the metal-CuS/MoS2 composite coating. Metal- and CuS-doped MoS2 solid solution is a practical component in composite coatings. The wear scar of the composite coatings showed different color layers at different annealing temperatures due to composition deviation. After heat treatment at 320 °C, the friction coefficient of Cu-CuS/MoS2 coating was reduced to a minimum of 0.08. After heat treatment at 420 °C, the Al-CuS/MoS2 coating showed three different color layers of wear scar, and good tribological properties were obtained. The friction coefficient of the Al-CuS/MoS2 coating was as low as 0.06, and the adhesion of the Al-CuS/MoS2 coating was expressed in the HF1 level. The results show that the vacuum heat treatment can stimulate the action of CuS by forming a solid solution with MoS2, complementing the missing S atom during the sputtering deposition of MoS2 and improving the lubrication of the composite coating. In addition, although the action mechanisms are different, Cu and Al doping are all conducive to obtaining composite coatings with better tribological properties. [ABSTRACT FROM AUTHOR]

In this study, GO/ZnO/Ag nanocomposites were prepared by a hydrothermal method in one step. The microstructure and surface morphology of the material were analyzed by x-ray diffraction and a scanning electron microscope. The chemical interactions between the available oxygen functional groups of reduced graphene oxide and the inorganic parts (Ag and ZnO) were analyzed by XPS and FTIR. The synergistic antibacterial activity of the nanocomposites against Streptococcus mutans was investigated. It was confirmed that GO/ZnO/Ag could inhibit the growth of S. mutans. The minimal inhibitory concentration and minimum bactericidal concentration of GO/ZnO/Ag on the surface structure of S. mutans were 62.5 and 125 µg/ml, respectively. The material was added to a dental dentin binder, and the modified dentin binder specimens with GO/ZnO/Ag had a significant antibacterial effect against Streptococcus mutans. The results showed that a low dose of GO/ZnO/Ag did not affect the shear bond strength of the dentin binder (P > 0.05), while a high dose of GO/ZnO/Ag decreased the shear bond strength of the dentin binder (P < 0.05). With an increase in GO/ZnO/Ag, the contact angle of the modified dentin binder specimens decreased and the hydrophilicity increased. The nanocomposites can not only be used as antibacterial agents but also have potential applications in biomedical fields. [ABSTRACT FROM AUTHOR]

The mechanical properties characterization of silicon nanowires is generally performed by tensile nanomechanical loading tests with in situ strain quantification. While the strain is characterized by electron beam (e-beam) microscopy techniques, the understanding of the sample-electron interaction is essential to guarantee artifact-free measurements. In this work, we investigated suspended strained silicon nanowires under electron beam exposure in a scanning electron microscope (SEM). The fabricated nanowires had their initial stress profile characterized by Raman spectroscopy and finite element method simulations. Then, the sample was exposed to an e-beam where we observed a gradual electrical charging of the sample, verified by the image drift, and down deflection of the suspended nanowire caused by electrostatic forces. These additional stresses induced the mechanical fracture of the nanowires in the corner region due to accumulated stress. These results ascribe electrostatic mechanical loading concerns that may generate undesirable additional stresses in nanomechanical tests performed in SEM, demonstrating the importance of proper sample preparation to avoid electrostatic charging effects. Here, we propose a simple and effective method for imposing the structures under an impinging electron beam at an equipotential, which mitigates the charging effects acting on the nanowire. [ABSTRACT FROM AUTHOR]

We have successfully deposited a thin film of rare earth oxide on a Si substrate. After morphological characterization via a scanning electron microscope and an atomic force microscope, the electrical properties of the Al/Dy2O3/Si MOS structure were investigated using the current–voltage I(V) and capacitance–voltage C(V) measurements, as well as a study in the dynamic regime (AC) via conductance–frequency σ(f) measurements at different temperatures. Based on the classical Schottky model, we were able to determine some physical parameters, namely, the ideality factor and the potential barrier height. The effect of resistance and interface states on the current–voltage characteristics is observable and results in a deviation from the ideality factor. Then, dielectric data have been acquired by means of impedance spectroscopy over a wide frequency and temperature range. These results show that understanding the temperature dependence of the electrical characteristics of this structure may be of great help in improving the quality of Dy2O3 developed on a Si substrate for the future of device technology. [ABSTRACT FROM AUTHOR]

Surface texture has aroused widespread interest due to its role in controlling friction, reducing wear, and improving lubrication performance. As one of the most promising green processing technologies, Laser Powder Bed Fusion (LPBF) can manufacture complex structures, effectively reducing manufacturing constraints and significantly increasing structural design freedom. In this study, the powder bed model was established by numerical simulation, and the influence of different energy inputs on the morphology and characteristics of the molten pool was investigated. Based on this, the optimal forming process parameters of CuSn10 were selected. In addition, LPBF is used to process different textures (square texture, circular texture, hemispheric texture, and triangle texture) on the surface of CuSn10. The surface texture's structural accuracy, surface morphology, and wettability were studied using a profiler, scanning electron microscope, and contact angle measuring instrument, respectively. The research results show that the accuracy of the square texture structure is the closest to the original design model among all the samples and the hemispheric texture surface does not have severe powder adhesion; as a result, it has the lowest average surface roughness of 5.58 µm. However, the triangle texture has the worst formation quality. It was revealed that the stepping effect mechanism of irregularly formed surfaces is the most important reason to cause this phenomenon. In addition, the maximum contact angle of the square texture is 85.59°, which is 15.76% higher than that of the triangle texture. [ABSTRACT FROM AUTHOR]

The photocurrent from a semiconductor photocathode with a negative-electron affinity surface can be arbitrarily controlled by the excitation laser power. Applying this characteristic to a scanning electron microscope allows the probe current to be arbitrarily controlled at any location on the sample. A photocathode with a fast time response is required to control the probe current at high speed. This study used an InGaN photocathode for pulsed electron beam generation and investigated its time response. A pulsed electron beam with 3.8 ns pulse width and 8.1 × 103 A cm−2 current density was observed, and the rise and fall times of the photocurrent were found to be 1.7 and 2.0 ns, respectively. The results show that despite the bottleneck of the time response of the laser power, the InGaN photocathode generates an electron beam that can control the probe current on a pixel-by-pixel for a 270 MHz scan speed. [ABSTRACT FROM AUTHOR]

Pulsed electron beams from a photocathode using an InGaN semiconductor have brought selectively scanning technology to scanning electron microscopes, where the electron beam irradiation intensity and area can be arbitrarily selected within the field of view in SEM images. The p-type InGaN semiconductor crystals grown in the metalorganic chemical vapor deposition equipment were used as the photocathode material for the electron beam source after the surface was activated to a negative electron affinity state in the electron gun under ultrahigh vacuum. The InGaN semiconductor photocathode produced a pulsed electron beam with a rise and fall time of 3 ns, consistent with the time structure of the irradiated pulsed laser used for the optical excitation of electrons. The InGaN photocathode-based electron gun achieved a total beam operation time of 1300 h at 15 μA beam current with a downtime rate of 4% and a current stability of 0.033% after 23 cycles of surface activation and continuous beam operation. The InGaN photocathode-based electron gun has been installed in the conventional scanning electron microscope by replacing the original field emission gun. SEM imaging was performed by selective electron beaming, in which the scanning signal of the SEM system was synchronized with the laser for photocathode excitation to irradiate arbitrary regions in the SEM image at arbitrary intensity. The accuracy of the selection of regions in the SEM image by the selective electron beam was pixel by pixel at the TV scan speed (80 ns/pix, 25 frame/s) of the SEM. [ABSTRACT FROM AUTHOR]

Quantitatively accurate, physics-based, computational modeling of etching and lithography processes is essential for modern semiconductor manufacturing. This paper presents lithography and etch models for a trilayer process in a back end of the line manufacturing vehicle. These models are calibrated and verified against top-down scanning electron microscope (SEM) and cross-sectional SEM measurements. Calibration errors are within 2 nm, while the maximum verification error is less than 3 nm. A fluorocarbon plasma etch of the spin-on-glass (SOG) layer accounts for most of the etch bias present in the process. The tapered profile in the SOG etch step is generated due to the polymerization process by fluorocarbon radicals generated in the plasma. The model predicts a strong correlation between the etch bias in the SOG etch step and the neutral-to-ion flux ratio in the plasma. The second etch step of the flow, which etches the spin-on-carbon (SOC) layer using an H2/N2 plasma, results in a negative etch bias (increase in CDs) for all measured features. The ratio of hydrogen to nitrogen radical fluxes effectively controls the etch bias in this step, with the model predicting an increase in the etch bias from negative to positive values as the H-to-N ratio decreases. The model also indicates an aspect ratio dependent etch rate in the SOG and SOC etch steps, as seen in the etch front evolution in a three-dimensional test feature. The third and final step of the process, SiO2-etch, generates an insignificant etch bias in all the test structures. Finally, the accuracy of the etch simulations is shown to be dependent on the accuracy of the incoming photoresist shapes. Models that consider only the top-down SEM measurement as input and do not account for an accurate photoresist profile, suffered significant errors in the post-etch CD predictions. [ABSTRACT FROM AUTHOR]

To test the effect of pre-curing time on the impact resistance of reactive powder concrete (RPC), RPC specimens were cured in a steam curing box at a temperature of 70 °C for 72 h with pre-curing times of 18, 24, and 30 h. At 28 days, the low-speed impact test was carried out on RPC specimens with a Ceast9350 drop weight impact system at an impact rate of 5 m/s and impact energy of 140 J. The variation curves of the impact force and displacement of RPC specimens with impact times were obtained. The results show that the impact resistance of RPC specimens improved with the increased pre-curing time, implying that appropriate pre-curing time (30 h in this case) can improve RPC mechanical properties. At the same time, combined with x-ray diffraction, scanning electron microscope imaging of hydration products, and the energy dispersion spectroscopy test, the influence mechanism of pre-curing time on the impact resistance of RPC is analyzed from the microstructure standpoint. The results show that appropriate pre-curing time can make the hydration of cement form finer particles and make the hardened paste form a protective structure to reduce the damage of steam curing in the strength development process. Through multiscale homogenization calculation via the Mori–Tanaka scheme, it can be seen that RPC's stiffness increases with the prolonged pre-curing time. Optimizing pre-curing time is conducive to improving the mechanical properties of RPC specimens. [ABSTRACT FROM AUTHOR]

The electronic spins of rare-earth materials are attractive candidates for spin qubits and quantum memories. To access individual spins, tuning of the g-factor is desirable. Here, we report on local strain-dependent g-factors of the 5D0–7F2 transitions of Eu3+ centers in GaN:Eu thin films. We have found a clear correlation between the effective g-factor and the emission energy shift induced by the local strain. The combination of micro-photoluminescence and scanning electron microscope/electron backscattering diffraction measurements has revealed that the compressive strain of 0.2%–0.4%, relative to a surrounding reference point, induces an energy shift of about 3 meV. The strain decreases the g-factor of the emission at 1.991 eV from 2.5 to 1.5, while the strain increases the g-factor of the emission at 1.994 eV from 1.1 to 1.7. The result suggests that the g-factor can be tuned by the local strain. On the basis of the strain-induced energy shift and the g-factor, we have identified the optical sites. The 5D0–7F2 transitions observed in this study consist of three optical sites with C3v symmetry and one site with C1h symmetry. [ABSTRACT FROM AUTHOR]

To improve the photocatalytic activity of titanium oxide, nanometer titanium oxide powder was mixed with a phosphoric acid solution to form an electrolyte for preparing TiO2/Al2O3 coating on the surface of an aluminum alloy. Hydrothermal technology has been used to adjust the crystalline structure of nanometer titanium oxide. Scanning electron microscope was used to observe the micromorphology of anodic coating before and after treatment using hydrothermal technology. Results indicated that the photocatalyst had a porous structure. Energy dispersive spectrometry, x-ray diffraction, and x-ray photoelectron spectroscopy were used to confirm that titanium oxide was dispersed in the coating. The photocatalyst was used to degrade the methyl orange solution, and its absorbance before and after treatment by catalyst was tested by UV–vis spectroscopy. The results indicated that methyl orange could be degraded when the doping amount of titanium oxide is 8 g/l for 100 min. [ABSTRACT FROM AUTHOR]

Integrated interferometry installed on top of dry etch equipment was developed for the in-process measurement of critical dimension (CD) in vertical NAND flash memory dry etch forming word-line steps, also known as word-line processes. The etching process sequentially consists of mask trimming and mold etching (multilayered structure of Si3N4 and SiO2). In-process real-time CD measurements can be made in a trimming step that etches the photoresist (PR) to form a vertical mask shape. The measurement principle is based on the analysis of the interference fringe signal of light reflection to a single point in the center of the wafer. To check the measurement accuracy of the interferometer, the CD measured with interferometry was compared with an in-line SEM (scanning electron microscope). The correlation coefficient between the interferometric measurements measured during the mask trimming step and the in-line SEM measured after the completed process was 86%. On the other hand, when the mask trimming and the mold etching steps including Si3N4 over etching were added, the total measurement results showed that the correlation coefficient was 95%. This is because the CD value was derived based on the phenomenon that the PR thickness change measured by interferometry in the trimming step was a linear relationship with the change in the lateral PR amount, so the lateral PR amount was weakly etched in the mold etching step after the trimming step, which eventually affected the final formed CD. This metrology method can be simply applied to dry etching equipment in real production lines. [ABSTRACT FROM AUTHOR]

The electrostatic discharge (ESD) from polymer insulators is one of the environment-related anomalies on spacecraft. Theoretically, to mitigate the ESD effects, we could modulate the secondary electron yield (SEY, σ) close to 1 in the entire energy range, suppressing surface charges. However, no single polymer insulator has been reported to achieve this seesaw-type modulation of SEY. Here, we exploringly designed and prepared MgO particles doped polytetrafluoroethylene (PTFE) composite coating to achieve this goal, which exhibits not only the reduced SEY characteristic of the microstructured PTFE coating at low energy but also the enhanced SEY characteristic of the double-layer structure of PTFE and MgO at high energy. The simulation and experiment results demonstrate that MgO particles doped PTFE coating achieves this seesaw-type modulation of SEY. The optimal MgO concentration is 20%, where the maximum SEY (σmax) changes from 2.0 to 1.1; the SEY at 10 keV (σ10k) changes from 0.6 to 0.8, and the higher energy of the SEY equal to 1 (Ep2) increases from 4.5 to 6.5 keV. The discharge test of the microstrip antennas with PTFE-MgO composite coating in a scanning electron microscope verifies the role of the seesaw-type SEY modulation in surface charge suppression. This study supplies an essential reference for suppressing surface charges on vacuum electronics based on modulation of secondary electron emission characteristics. [ABSTRACT FROM AUTHOR]

TiSiCN composite coatings with different N contents based on Cr buffer layer were prepared by plasma-enhanced magnetron sputtering. The surface and cross-sectional morphology, composition, and structure of the coatings were evaluated by scanning electron microscope with energy dispersive spectroscopy, atomic force microscope, x-ray photoelectron spectroscopy, x-ray diffraction, and Raman spectroscopy. The hardness, elastic modulus, and tribological performance were investigated. The results showed that with the addition of N content, the proportion of sp3-hybrized C bonds and amorphous Si3N4 in TiSiCN coatings gradually decreased, while the proportion of graphite phase and CNx gradually increased. The decrease in the sp3—C bonding ratio leads to the decrease of coating hardness, and the composite coating with N content of 7.3% has the highest hardness at 13.2 GPa. The friction experiments exhibited the self-lubrication feature of the internal graphite phase, and the strengthening of moderate amounts of the hard phase can significantly reduce the wear rate. The TiSiCN composite coating with N content of 13.2% had the lowest wear rate. [ABSTRACT FROM AUTHOR]

Cu/SiO2 hybrid bonding has been developed for the application of heterogeneous bond interfaces in 3D integrated circuits in which thermal stability and bonding behavior are important. Thus, nano-twinned Cu (NT-Cu) is selected as the bonding material, and the thermal stability of NT-Cu and the bonding behavior of the interface between NT-Cu are investigated using a scanning electron microscope, electron backscatter diffraction, and focused ion beam. In addition to the microstructure analysis, nano-indentation and nano-scratch are employed to characterize the mechanical properties of the matrix and the interface between NT-Cu. As the bonding temperature increases from 200 to 300 °C for NT-Cu, the average grain sizes increase from 0.64 to 0.87 µm, and the rate of grain coarsening increases from 0.14 to 0.25 µm/h1/2. In addition, the fraction of voids at the bonding interface for NT-Cu interconnects decreases from 0.814% to 0.005%, and the penetration depth increases from 228 to 745 nm with an increase in the temperature from 200 to 300 °C. The hardness of the bonding interface obtained by nano-scratch and nano-indentation array testing is ∼1.8 GPa. [ABSTRACT FROM AUTHOR]

Good specimen quality is a key factor in achieving successful scanning transmission electron microscope analysis. Thin and damage-free specimens are prerequisites for obtaining atomic-resolution imaging. Topological insulator single crystals and thin films in the chalcogenide family such as Sb2Te3 are sensitive to electron and ion beams. It is, therefore, challenging to prepare a lamella suitable for high-resolution imaging from these topological insulator materials using standard focused ion-beam instruments. We have developed a modified method to fabricate thin focused ion-beam (FIB) lamellae with minimal ion-beam damage and artifacts. The technique described in the current study enables the reliable preparation of high-quality transmission electron microscope (TEM) specimens necessary for studying ultra-thin surface regions. We have successfully demonstrated that the careful selection of FIB milling parameters at each stage minimizes the damage layer without the need for post-treatment. [ABSTRACT FROM AUTHOR]