Showing papers on "Focused ion beam published in 2016"
TL;DR: In this article, a symmetrical Fe2O3/BaCO3 hexagonal cone structure with a height of 10 μm and edge length of 4 μm was obtained using a common solvothermal process and a mirror growth process.
Abstract: A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 μm and an edge length of ~4 μm is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2–18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.
214 citations
TL;DR: The development of a cryo-stage allowing for spinning-disk confocal light microscopy at cryogenic temperatures is presented and the incorporation of the new hardware into existing workflows for cellular sample preparation bycryo-FIB is described.
158 citations
TL;DR: It is demonstrated that focused ion beam (FIB) fabricated nanowires of TIs could be used as ultrasensitive visible-NIR nanowire photodetector based on TIs.
Abstract: Recently, very exciting optoelectronic properties of Topological insulators (TIs) such as strong light absorption, photocurrent sensitivity to the polarization of light, layer thickness and size dependent band gap tuning have been demonstrated experimentally. Strong interaction of light with TIs has been shown theoretically along with a proposal for a TIs based broad spectral photodetector having potential to perform at the same level as that of a graphene based photodetector. Here we demonstrate that focused ion beam (FIB) fabricated nanowires of TIs could be used as ultrasensitive visible-NIR nanowire photodetector based on TIs. We have observed efficient electron hole pair generation in the studied Bi2Se3 nanowire under the illumination of visible (532 nm) and IR light (1064 nm). The observed photo-responsivity of ~300 A/W is four orders of magnitude larger than the earlier reported results on this material. Even though the role of 2D surface states responsible for high reponsivity is unclear, the novel and simple micromechanical cleavage (exfoliation) technique for the deposition of Bi2Se3 flakes followed by nanowire fabrication using FIB milling enables the construction and designing of ultrasensitive broad spectral TIs based nanowire photodetector which can be exploited further as a promising material for optoelectronic devices.
123 citations
TL;DR: This work proposes and demonstrates an approach to reliably and rapidly define plasmonic nanoparticles and their assemblies using FIB milling via a simple "sketch and peel" strategy and demonstrates that this strategy is also applicable to the state-of-the-art helium ion beam milling technology, with which high-fidelity plAsmonic dimers with tiny gaps could be directly and rapidly prototyped.
Abstract: Focused ion beam (FIB) milling is a versatile maskless and resistless patterning technique and has been widely used for the fabrication of inverse plasmonic structures such as nanoholes and nanoslits for various applications. However, due to its subtractive milling nature, it is an impractical method to fabricate isolated plasmonic nanoparticles and assemblies which are more commonly adopted in applications. In this work, we propose and demonstrate an approach to reliably and rapidly define plasmonic nanoparticles and their assemblies using FIB milling via a simple “sketch and peel” strategy. Systematic experimental investigations and mechanism studies reveal that the high reliability of this fabrication approach is enabled by a conformally formed sidewall coating due to the ion-milling-induced redeposition. Particularly, we demonstrated that this strategy is also applicable to the state-of-the-art helium ion beam milling technology, with which high-fidelity plasmonic dimers with tiny gaps could be direct...
94 citations
TL;DR: Optical fiber micro-tips are promising devices for sensing applications in small volume and difficult to access locations, such as biological and biomedical settings with sensitivities of - 15.8 pm/K and -1316 nm/RIU, respectively.
Abstract: Optical fiber micro-tips are promising devices for sensing applications in small volume and difficult to access locations, such as biological and biomedical settings. The tapered fiber tips are prepared by dynamic chemical etching, reducing the size from 125 μm to just a few μm. Focused ion beam milling is then used to create cavity structures on the tapered fiber tips. Two different Fabry-Perot micro-cavities have been prepared and characterized: a solid silica cavity created by milling two thin slots and a gap cavity. A third multi-cavity structure is fabricated by combining the concepts of solid silica cavity and gap cavity. This micro-tip structure is analyzed using a fast Fourier transform method to demultiplex the signals of each cavity. Simultaneous measurement of temperature and external refractive index is then demonstrated, presenting sensitivities of - 15.8 pm/K and −1316 nm/RIU, respectively.
89 citations
TL;DR: In this article, the authors used focused ion beam (FIB) cut cross-sections to fill the pores between CNT bundles from FIB cut crosssections, showing that aqueous based electrolytes can fill micropores between as-spun CNTs in a fiber network.
84 citations
TL;DR: In this article, a local thresholding algorithm is used to extract the catalyst layer pore morphology from focused ion beam scanning electron microscopy (FIB-SEM) images, and n-point correlation functions, such as auto-correlation, chord length, and pore-size distribution are computed to interpret the micro-structure variations between different images of the same catalyst layer.
Abstract: Image analysis and numerical simulation algorithms are introduced to analyze the micro-structure, transport, and electrochemical performance of thin, low platinum loading inkjet printed electrodes. A local thresholding algorithm is used to extract the catalyst layer pore morphology from focused ion beam scanning electron microscopy (FIB-SEM) images. n-point correlation functions, such as auto-correlation, chord length, and pore-size distribution are computed to interpret the micro-structure variations between different images of the same catalyst layer. Pore size distributions are in agreement with experimental results. The catalyst layer exhibits anisotropy in the through-plane direction, and artificial anisotropy in the FIB direction due to low slicing resolution. Microscale numerical mass transport simulations show that transport predictions are affected by image resolution and that a minimum domain size of 200 nm is needed to estimate transport properties. A micro-scale electrochemical model that includes a description of the ionomer film resistance and a multi-step electrochemical reaction model for the oxygen reduction reaction is also presented. Results show that the interfacial mass transport resistance in the ionomer film has the largest effect on the electrochemical performance.
84 citations
TL;DR: The results strongly suggest that dislocation self-organization is a key elementary mechanism for the microstructure evolution under a tribological load and the distinct elementary processes at different stages of sliding identified here will be essential for the future modeling of the microStructure evolution in tribological contacts.
Abstract: Tailoring the surface properties of a material for low friction and little wear has long been a goal of tribological research. Since the microstructure of the material under the contact strongly influences tribological performance, the ability to control this microstructure is thereby of key importance. However, there is a significant lack of knowledge about the elementary mechanisms of microstructure evolution under tribological load. To cover different stages of this microstructure evolution, high-purity copper was investigated after increasing numbers of sliding cycles of a sapphire sphere in reciprocating motion. Scanning electron and focused ion beam (FIB) microscopy were applied to monitor the microstructure changes. A thin tribologically deformed layer which grew from tens of nanometers to several micrometers with increasing number of cycles was observed in cross-sections. By analyzing dislocation structures and local orientation changes in the cross-sectional areas, dislocation activity, the occur...
83 citations
TL;DR: The direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors is reported, demonstrating the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) forperovskite photonic nanostructures.
Abstract: The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells ...
82 citations
TL;DR: In this paper, the authors evaluated β-Ga2O3 crystals grown by edge-defined film-fed growth process using etch pitting, focused ion beam scanning ion microscopy, transmission electron microscopy and related techniques.
Abstract: We have structurally evaluated β-Ga2O3 crystals grown by edge-defined film-fed growth process using etch pitting, focused ion beam scanning ion microscopy, transmission electron microscopy, and related techniques. We found three types of defects: arrays of edge dislocations corresponding to etch pit arrays on -oriented wafers, platelike nanopipes corresponding to etch pits revealed on the (010)-oriented wafers, and twins including twin lamellae.
81 citations
TL;DR: In this paper, a detailed characterization of freestanding bilayer (Au-TiW) micro-cantilevers and double clamped beams, for applications as Radio Frequency (RF)-switches Micro-Electromechanical Systems (MEMS), is presented.
TL;DR: In this paper, the effect of wire wear on the surface morphology, roughness, and subsurface damage of single crystal silicon wafers was analyzed using scanning electron microscopy, Raman spectroscopy, confocal microscopy and focused ion beam machining (FIB).
TL;DR: In this paper, the porosity, Euler number (pore connectivity), overall roughness, solid phase size and pore size are calculated for catalyst surfaces and volumes using scanning electron microscopy (SEM) and focused ion beam (FIB) tomography.
TL;DR: In this paper, the behavior of freestanding graphene subjected to bombardment of energetic ions is investigated, and the capability of large-scale patterning of 2D lattices with nanometer sized features by focused ion beam technology is shown.
Abstract: We report experimentally and theoretically the behavior of freestanding graphene subjected to bombardment of energetic ions, investigating the capability of large-scale patterning of freestanding graphene with nanometer sized features by focused ion beam technology. A precise control over the He+ and Ga+ irradiation offered by focused ion beam techniques enables investigating the interaction of the energetic particles and graphene suspended with no support and allows determining sputter yields of the 2D lattice. We found a strong dependency of the 2D sputter yield on the species and kinetic energy of the incident ion beams. Freestanding graphene shows material semi-transparency to He+ at high energies (10–30 keV) allowing the passage of >97% He+ particles without creating destructive lattice vacancy. Large Ga+ ions (5–30 keV), in contrast, collide far more often with the graphene lattice to impart a significantly higher sputter yield of ∼50%. Binary collision theory applied to monolayer and few-layer graphene can successfully elucidate this collision mechanism, in great agreement with experiments. Raman spectroscopy analysis corroborates the passage of a large fraction of He+ ions across graphene without much damaging the lattice whereas several colliding ions create single vacancy defects. Physical understanding of the interaction between energetic particles and suspended graphene can practically lead to reproducible and efficient pattern generation of unprecedentedly small features on 2D materials by design, manifested by our perforation of sub-5 nm pore arrays. This capability of nanometer-scale precision patterning of freestanding 2D lattices shows the practical applicability of focused ion beam technology to 2D material processing for device fabrication and integration.
TL;DR: The precipitation evolution during ageing of a 2101 lean duplex stainless steel was investigated, revealing that the precipitate type and morphology depends on the nature of the grain boundary.
TL;DR: In this article, a 3D microstructural study was performed on both pristine and cycled LiNixMnyCo1−x−yO2 (NMC) and Li(Li 0.2Ni0.13Mn0.54Co 0.13 O2 (HE-NMC), and the spatial distribution of active material, carbon-doped binder and pore spaces were successfully reconstructed by appropriate image processing.
TL;DR: In this paper, an improved ion beam layer removal method is developed to determine the stress distribution in copper and tungsten-based thin film systems, and the residual stress profiles were determined with a depth resolution of 50nm, employing the ion beam removal method.
TL;DR: A photoresist-free focused ion beam (FIB) method to pattern as-grown TMDC monolayers by chemical vapor deposition, where the exposed edges from FIB etching serve as the seeds for growing a second TMDC material to form desired lateral heterostructures with arbitrary layouts.
Abstract: Two-dimensional transition metal dichalcogenides (TMDCs) have shown great promise in electronics and optoelectronics due to their unique electrical and optical properties. Heterostructured TMDC layers such as the laterally stitched TMDCs offer the advantages of better electronic contact and easier band offset tuning. Here, we demonstrate a photoresist-free focused ion beam (FIB) method to pattern as-grown TMDC monolayers by chemical vapor deposition, where the exposed edges from FIB etching serve as the seeds for growing a second TMDC material to form desired lateral heterostructures with arbitrary layouts. The proposed lithographic and growth processes offer better controllability for fabrication of the TMDC heterostrucuture, which enables the construction of devices based on heterostructural monolayers.
TL;DR: In this article, a new yttrium-containing W-Cr-Y alloys were tested in a thermo-gravimetric facility and they showed a parabolic oxidation rate of 3 · 10 − 6 mg 2 cm − 4 s − 1 which is more than five orders of magnitude lower than that of pure tungsten at 1273 K and 1473 K, respectively.
Abstract: Tungsten is a prime material candidate for the first wall of a future fusion reactor. In the case of a loss-of-coolant accident (LOCA) wall temperatures of about 1450 K could be reached lasting about 30–60 days due to nuclear decay heat. In the worst case scenario combining LOCA with air ingress, the formation and release of highly volatile and radioactive tungsten trioxide (WO3) into the environment can occur. Smart self-passivating tungsten alloys preventing the formation of WO3 can be a way to mitigate this release. In this contribution we present the studies of a new yttrium-containing W-Cr-Y alloys. The extent up to which yttrium acts as an active element improving the adherence and stability of the protective Cr2O3 layer formed during oxidation is assessed. The approach is similar to the one taken for high-temperature steels where active elements stabilize the oxide layers at a substantially reduced thickness by changing the oxygen diffusion and improving the adherence of the protective oxide layer by e.g. avoiding of pores. Further, simulations on mobilized material for the case of a LOCA are developed. In addition, the loss of alloying elements during normal operation of a reactor is estimated. This is done by modelling a thermally activated diffusion, using a diffusion coefficient which is extrapolated from experimental data at higher values. The oxidation behaviour of magnetron sputtered and therefore alloyed at the atomic level W-Cr-Y alloys is tested in a thermo-gravimetric facility. The isothermal oxidations are performed in a gas mixture, containing 20 kPa oxygen and 80 kPa argon under ambient pressure at temperatures of 1273 K and 1473 K, respectively. Experiments with W-Cr-Y show a parabolic oxidation rate of k p = 3 · 10 − 6 mg 2 cm − 4 s − 1 which is more than five orders of magnitude lower than that of pure tungsten at 1273 K. Investigations using X-ray diffraction analysis and focused ion beam cross-sections in combination with scanning electron microscopy and energy dispersive X-ray spectroscopy are conducted. A protective Cr2O3 layer is detected on the surface with a thickness between 100 and 300 nm.
TL;DR: In this article, the effect of the gallium-milled notch on mode I toughness quantification was investigated and it was found that notching using a focused gallium source can lead to an overestimation of the fracture toughness values for chromium nitride (CrN) thin films.
Abstract: For the implementation of thin ceramic hard coatings into intensive application environments, the fracture toughness is a particularly important material design parameter. Characterisation of the fracture toughness of small-scale specimens has been a topic of great debate, due to size effects, plasticity, residual stress effects and the influence of ion penetration from the sample fabrication process. In this work, several different small-scale fracture toughness geometries (single-beam cantilever, double-beam cantilever and micro-pillar splitting) were compared, fabricated from a thin physical vapour-deposited ceramic film using a focused ion beam source, and then the effect of the gallium-milled notch on mode I toughness quantification investigated. It was found that notching using a focused gallium source influences small-scale toughness measurements and can lead to an overestimation of the fracture toughness values for chromium nitride (CrN) thin films. The effects of gallium ion irradiation w...
TL;DR: In this article, a microscopic three-point bending test that measures the strength of faceted particles of high aspect ratio is developed and used to probe individual coarsened plate-like silicon particles extracted from the eutectic Al-12.6%Si alloy.
TL;DR: In this article, a triangular prism is machined via focused ion beam (FIB) and contains two ferritic grains, and four experimental tools are integrated to identify the material's crystal parameters: an optical confocal microscope captures height profile images, an in-situ tensile stage prescribes the loading history to the macrospecimen, a global Digital Image Correlation algorithm measures the 3D surface displacement fields, and an extension of Integrated-DIC for 3D displacement fields is implemented to assess the micromechanical behavior.
TL;DR: In this paper, the microstructural evolution and chemistry of the ferrite phase (α), which transforms from the parent austenite phase (γ) of 316L stainless steel during gallium ion beam implantation in Focused Ion Beam (FIB) instrument was systematically studied as a function of Ga+ ion dose and γ grain orientations.
TL;DR: In this paper, a micro-mechanical technique is used to determine values of the critical stress intensity factor for fracture for grain boundaries of various orientations in Ni alloy 600 exposed to Pressurized Water Reactor (PWR) primary water at 325 °C with a hydrogen partial pressure of 30 kPa.
TL;DR: In this article, a focused ion beam implemented in the analysis chamber of a state-of-the-art secondary ion mass spectrometer was used to perform detailed mapping of elements distribution, including lithium, inside a silicon particle or in the entire depth of the electrode.
Abstract: Considering its specific capacity, silicon is one of the most promising materials to replace graphite in lithium ion batteries anodes. However, its rapid capacity fading prevents its use in current batteries. Understanding lithiation and degradation mechanisms of silicon is important for improving its cyclability. In this work a novel approach is developed by using a focused ion beam implemented in the analysis chamber of a state-of-the-art time of flight secondary ion mass spectrometer. Detailed mapping of elements distribution, including lithium, inside a silicon particle or in the entire depth of the electrode, can thus be performed. During the first lithiation, a core–shell mechanism is observed and its evolution upon electrochemical cycling was examined. This mechanism is observed for all particles in the electrode, independently of their position. Cross analysis with Auger spectroscopy allowed Li concentration in the entire shell to be quantified. Fast lithiation paths getting through the pure silic...
TL;DR: In this paper, diamond nanopillars were fabricated by focused ion beam (FIB) milling from synthetic single crystals and compressed using a larger diameter diamond punch, which corresponded to maximum shear stresses that converged toward 75 GPa or ∼ G/7 at small sizes, which was very close to the ultimate theoretical yield stress estimate of G/2π.
Abstract: Diamond ⟨100⟩- and ⟨111⟩-oriented nanopillars were fabricated by focused ion beam (FIB) milling from synthetic single crystals and compressed using a larger diameter diamond punch. Uniaxial compressive failure was observed via fracture with a plateau in maximum stress of ∼0.25 TPa, the highest uniaxial strength yet measured. This corresponded to maximum shear stresses that converged toward 75 GPa or ∼ G/7 at small sizes, which are very close to the ultimate theoretical yield stress estimate of G/2π.
TL;DR: In this paper, a focused ion beam followed by electro-polishing was used to make thin foil specimens for transmission electron microscope observations, and the correlation between the microstructure and hardening was investigated.
Abstract: The irradiation hardening and microstructures of pure W and W – 3%Re for up to 5.0 dpa by self-ion irradiation were investigated in this work. The ion irradiation was conducted using 18 MeV W6+ at 500 and 800 °C. A focused ion beam followed by electro-polishing was used to make thin foil specimens for transmission electron microscope observations. Dislocation loops were observed in all the irradiated samples. Voids were observed in all of the specimens except the W–3%Re irradiated to 0.2 dpa. The hardness was measured by using nanoindentation. The irradiation hardening was saturated at 1.0 dpa for pure W. In the case of W – 3%Re, the irradiation hardening showed a peak at 1.0 dpa. The correlation between the microstructure and hardening was investigated.
TL;DR: In this article, the authors proposed a Liquid Metal Alloy Ion Sources (LMAIS) for focused ion beam (FIB) processing, which can be tuned by choosing a well suited LMAIS.
Abstract: Today, Focused Ion Beam (FIB) processing is nearly exclusively based on gallium Liquid Metal Ion Sources (LMIS) But, many applications in the μm- or nm range could benefit from ion species other than gallium: local ion implantation, ion beam mixing, ion beam synthesis, or Focused Ion Beam Lithography (IBL) Therefore, Liquid Metal Alloy Ion Sources (LMAIS) represent a promising alternative to expand the remarkable application fields for FIB Especially, the IBL process shows potential advantages over, eg, electron beam or other lithography techniques: direct, resistless, and three-dimensional patterning, enabling a simultaneous in-situ process control by cross-sectioning and inspection Taking additionally into account that the used ion species influences significantly the physical and chemical nature of the resulting nanostructures—in particular, the electrical, optical, magnetic, and mechanic properties leading to a large potential application area which can be tuned by choosing a well suited LMAIS
TL;DR: In this paper, the structural degradation of a laboratory Li-ion battery LiFePO4/Carbon Black (LFP/CB) cathode by various electron microscopy techniques including low kV Focused Ion Beam (FIB)/Scanning Electron Microscopy (SEM) 3D tomography was studied.