Showing papers on "Focused ion beam published in 2019"
TL;DR: It is demonstrated that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport with enhanced electron self-focusing effects, suggesting a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermani surfaces.
Abstract: Geometric electron optics may be implemented in solids when electron transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport. We probe this directional ballistic regime in a single crystal of PdCoO2 by use of focused ion beam (FIB) micro-machining, defining crystalline ballistic circuits with features as small as 250 nm. The peculiar hexagonal Fermi surface naturally leads to enhanced electron self-focusing effects in a magnetic field compared to circular Fermi surfaces. This super-geometric focusing can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material. These results suggest a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermi surfaces. Ballistic electron beams in clean metals can be focused by passing currents through well designed contraptions, which is mostly done in isotropic materials described by a circular Fermi surface. Here, the authors demonstrate that the almost hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport with enhanced electron self-focusing effects.
123 citations
TL;DR: In this article, the authors explore the cryogenic focused ion beam (cryo-FIB) method as a quantitative tool for characterizing the bulk morphology of electrochemically deposited lithium and as a technique that enables TEM observation of Li-metal/solid state electrolyte interfaces.
Abstract: Lithium metal is viewed as the ultimate battery anode because of its high theoretical capacity and low electrode potential, but its implementation has been limited by low Coulombic efficiency and dendrite formation above a critical current density. Determining the fundamental properties dictating lithium metal plating–stripping behavior is challenging because characterization techniques are limited by the sensitivity of lithium metal to damage by external probes, which regularly results in altered morphology and chemistry. Motivated by recent application of cryogenic transmission electron microscopy (cryo-TEM) to characterize lithium metal at the atomic scale, we explore the cryogenic focused ion beam (cryo-FIB) method as a quantitative tool for characterizing the bulk morphology of electrochemically deposited lithium and as a technique that enables TEM observation of Li-metal/solid-state electrolyte interfaces. This work highlights the importance of cryo-FIB methodology for preparing sensitive battery ma...
100 citations
TL;DR: It is demonstrated that using cryogenic FIB milling significantly reduces hydrogen pick-up during sample preparation of titanium and titanium alloys, allowing for hydrogen embrittlement mechanisms of Ti-based alloys to be investigated at the nanoscale.
Abstract: Hydrogen pick-up leading to hydride formation is often observed in commercially pure Ti (CP-Ti) and Ti-based alloys prepared for microscopic observation by conventional methods, such as electro-polishing and room temperature focused ion beam (FIB) milling. Here, we demonstrate that cryogenic FIB milling can effectively prevent undesired hydrogen pick-up. Specimens of CP-Ti and a Ti dual-phase alloy (Ti-6Al-2Sn-4Zr-6Mo, Ti6246, in wt.%) were prepared using a xenon-plasma FIB microscope equipped with a cryogenic stage reaching −135 °C. Transmission electron microscopy (TEM), selected area electron diffraction, and scanning TEM indicated no hydride formation in cryo-milled CP-Ti lamellae. Atom probe tomography further demonstrated that cryo-FIB significantly reduces hydrogen levels within the Ti6246 matrix compared with conventional methods. Supported by molecular dynamics simulations, we show that significantly lowering the thermal activation for H diffusion inhibits undesired environmental hydrogen pick-up during preparation and prevents pre-charged hydrogen from diffusing out of the sample, allowing for hydrogen embrittlement mechanisms of Ti-based alloys to be investigated at the nanoscale. Hydrogen contamination in metals during sample preparation for high-resolution microscopy remains a challenge, especially when hydrogen itself is being investigated. Here, the authors show that using cryogenic milling significantly reduces hydrogen pick-up during sample preparation of titanium and titanium alloys.
94 citations
TL;DR: It is shown that the formation of a nanometer-scale LM oxide in oxygen-rich environments allows highly nonwetting tungsten particles to mix into LMs, and the oxide-assisted mechanism behind this wetting process is revealed.
Abstract: Modern microelectronics and emerging technologies such as wearable devices and soft robotics require conformable and thermally conductive thermal interface materials to improve their performance and longevity. Gallium-based liquid metals (LMs) are promising candidates for these applications yet are limited by their moderate thermal conductivity, difficulty in surface-spreading, and pump-out issues. Incorporation of metallic particles into the LM can address these problems, but observed alloying processes shift the LM melting point and lead to undesirable formation of additional surface roughness. Here, these problems are addressed by introducing a mixture of tungsten microparticles dispersed within a LM matrix (LM-W) that exhibits two- to threefold enhanced thermal conductivity (62 ± 2.28 W m-1 K-1 for gallium and 57 ± 2.08 W m-1 K-1 for EGaInSn at a 40% filler volume mixing ratio) and liquid-to-paste transition for better surface application. It is shown that the formation of a nanometer-scale LM oxide in oxygen-rich environments allows highly nonwetting tungsten particles to mix into LMs. Using in situ imaging and particle dipping experimentation within a focused ion beam and scanning electron microscopy system, the oxide-assisted mechanism behind this wetting process is revealed. Furthermore, since tungsten does not undergo room-temperature alloying with gallium, it is shown that LM-W remains a chemically stable mixture.
92 citations
TL;DR: In this paper, a focused ion beam (FIB) was used to mill an array of patterned holes into 2D hexagonal boron nitride (hBN) to find arrays of bright, localized photoluminescence.
Abstract: Quantum emitters (QEs) in 2D hexagonal boron nitride (hBN) are extremely bright and are stable at high temperature and under harsh chemical conditions. Because they reside within an atomically thin 2D material, these QEs have a unique potential to couple strongly to hybrid optoelectromechanical and quantum devices. However, this potential for coupling has been underexplored because of challenges in nanofabrication and patterning of hBN QEs. Motivated by recent studies showing that QEs in hBN tend to form at edges, we use a focused ion beam (FIB) to mill an array of patterned holes into hBN. Using optical confocal microscopy, we find arrays of bright, localized photoluminescence that match the geometry of the patterned holes. Furthermore, second-order photon correlation measurements on these bright spots reveal that they contain single and multiple QEs. By optimizing the FIB parameters, we create patterned single QEs with a yield of 31%, a value close to Poissonian limit. Using atomic force microscopy to s...
76 citations
TL;DR: Recent progress in ion beam techniques for nanomaterial surface modification is systematically summarized and existing challenges and potential solutions are presented.
Abstract: Nanomaterials have gained plenty of research interest because of their excellent performance, which is derived from their small size and special structure. In practical applications, to acquire nanomaterials with high performance, many methods have been used to modulate the structure and components of materials. To date, ion beam techniques have extensively been applied for modulating the performance of various nanomaterials. Energetic ion beams can modulate the surface morphology and chemical components of nanomaterials. In addition, ion beam techniques have also been used to fabricate nanomaterials, including 2D materials, nanoparticles, and nanowires. Compared with conventional methods, ion beam techniques, including ion implantation, ion irradiation, and focused ion beam, are all pure physical processes; these processes do not introduce any impurities into the target materials. In addition, ion beam techniques exhibit high controllability and repeatability. Here, recent progress in ion beam techniques for nanomaterial surface modification is systematically summarized and existing challenges and potential solutions are presented.
66 citations
TL;DR: In this paper, a 30 kV focused ion beam was used to engineer defects and tailor the atomic, optoelectronic, and structural properties of monolayer transition metal dichalcogenides (TMDs).
Abstract: Manipulation and structural modifications of 2D materials for nanoelectronic and nanofluidic applications remain obstacles to their industrial-scale implementation. Here, it is demonstrated that a 30 kV focused ion beam can be utilized to engineer defects and tailor the atomic, optoelectronic, and structural properties of monolayer transition metal dichalcogenides (TMDs). Aberrationcorrected scanning transmission electron microscopy is used to reveal the presence of defects with sizes from the single atom to 50 nm in molybdenum (MoS2) and tungsten disulfide (WS2) caused by irradiation doses from 1013 to 1016 ions cm−2. Irradiated regions across millimeter-length scales of multiple devices are sampled and analyzed at the atomic scale in order to obtain a quantitative picture of defect sizes and densities. Precise dose value calculations are also presented, which accurately capture the spatial distribution of defects in irradiated 2D materials. Changes in phononic and optoelectronic material properties are probed via Raman and photoluminescence spectroscopy. The dependence of defect properties on sample parameters such as underlying substrate and TMD material is also investigated. The results shown here lend the way to the fabrication and processing of TMD nanodevices.
55 citations
TL;DR: In this paper, four positive electrodes are extracted from two high-power and two high energy Li-ion battery consumer cells, and then analyzed by focused ion beam-scanning electron microscopy (FIB-SEM) tomography.
42 citations
TL;DR: In this review, typical fabrication technologies for solid-state nanopores reported to date are summarized, with the advantages and limitations of each technology discussed in detail.
Abstract: Nanopores fabricated from synthetic materials (solid-state nanopores), platforms for characterizing biological molecules, have been widely studied among researchers. Compared with biological nanopores, solid-state nanopores are mechanically robust and durable with a tunable pore size and geometry. Solid-state nanopores with sizes as small as 1.3 nm have been fabricated in various films using engraving techniques, such as focused ion beam (FIB) and focused electron beam (FEB) drilling methods. With the demand of massively parallel sensing, many scalable fabrication strategies have been proposed. In this review, typical fabrication technologies for solid-state nanopores reported to date are summarized, with the advantages and limitations of each technology discussed in detail. Advanced shrinking strategies to prepare nanopores with desired shapes and sizes down to sub-1 nm are concluded. Finally, applications of solid-state nanopores in DNA sequencing, single molecule detection, ion-selective transport, and nanopatterning are outlined.
42 citations
TL;DR: In this paper, the effect of Ga on the microstructure and coercivity in Nd-rich Ga-doped nd-Fe-B sintered magnets with different amount of Ga additions was investigated using focused ion beam scanning electron microscope (FIB/SEM), aberration corrected scanning transmission electron microscopy (STEM), three dimensional atom probe (3DAP) and synchrotron X-ray diffraction.
40 citations
TL;DR: In this paper, the pore structure of a mature industrial high performance concrete (HPC) is characterized at the scale of its cement hydrates with 3D Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM).
TL;DR: In this paper, the performance of individual and multiple networked Au nanoparticles (NPs)-functionalized ZnO nanowires (NWs) integrated into nanosensor devices using dual beam focused ion beam/scanning electron microscopy (FIB/SEM) and tested them as gas sensors at room temperature.
Abstract: In this work, we investigated performances of individual and multiple networked Au nanoparticles (NPs)-functionalized ZnO nanowires (NWs) integrated into nanosensor devices using dual beam focused ion beam/scanning electron microscopy (FIB/SEM) and tested them as gas sensors at room temperature. Such important parameters as diameter and relative humidity (RH) on the gas sensing properties were investigated in detail. The presented results demonstrate that thin Au/ZnO NWs (radius of 60 nm) have a gas response of Igas/Iair of about 7.5–100 ppm of H2 gas which is higher compared to Igas/Iair of about 1.2 for NWs with a radius of 140 nm. They have a low dependence of electrical parameters on water vapors presence in environment, which is very important for practical and real time applications in ambient atmosphere. Also, the devices based on multiple networked Au/ZnO NWs demonstrated a higher gas response of Igas/Iair about 40 and a lower theoretical detection limit below 1 ppm compared to devices based on an individual NW due to the presence of multiple potential barriers between the NWs. The corresponding gas sensing mechanisms are tentatively proposed. The proposed concept and models of nanosensors are essential for further understanding the role of noble metal nanoclusters on semiconducting oxide nanowires and contribute for a design of new room-temperature gas sensors.
TL;DR: In this article, phase change material (PCM) germanium telluride (GeTe) based RF switches are investigated using atomic force microscopy, scanning electron microscopy (SEM), and cross-wafer resistance mapping measurements.
Abstract: This paper presents the characterization, optimization, and fabrication of phase change material (PCM) germanium telluride (GeTe) based RF switches investigating the materials’ aspect and design parameters of the switches and their impact on the RF performance. Surface properties of GeTe thin films are investigated through atomic force microscopy (AFM), scanning electron microscopy (SEM), and cross-wafer resistance mapping measurements. Optimized GeTe thin films exhibit over five orders of resistance change. Various GeTe switch design constraints are studied via cross sectioning of the fabricated device using a focused ion beam (FIB)-SEM. Current-carrying capacity and resistance of microheaters are extracted using electrical characterization. The RF performance of the PCM switches is optimized using diverse design parameters and characterization of PCM thin films. A six-layer microfabrication process is presented for monolithically integrating RF circuits with PCM switches. Methods to reduce parasitic elements in PCM switches are discussed. The RF performance of the optimized PCM based switch is simulated and measured demonstrating better than 0.4 dB of insertion loss and a return loss better than 20 dB from dc to 67 GHz.
TL;DR: FIBID-NbC is a promising material for the fabrication of superconducting nanowire single-photon detectors (SNSPD) and for the development of 3D superconductivity with applications in quantum information processing and nanoelectronics.
Abstract: Superconducting planar nanostructures are widely used in applications, e.g., for highly sensitive magnetometers and in basic research, e.g., to study finite size effects or vortex dynamics. In cont...
TL;DR: In this paper, the phase composition of cladding layer on diamond particles is analyzed by transmission electron microscopy combined with focused ion beam technology to measure the thermal conductivity of gallium-based thermal interface materials (TIMs).
Abstract: The focus of this paper is how to efficiently enhance the thermal conductance of gallium-based thermal interface materials (TIMs) and greatly avoid the excessive consumption of liquid metal during its application. Highly heat-conducting diamond particles are selected as the reinforced additives for pure gallium on account of their mature technology of surface metallization. To improve the interface combination status between those inorganic fillers and liquid metal matrix, chromium transition layer is deposited on the surfaces of diamond particles by magnetron sputtering method. The phase composition of cladding layer on diamond particles is analyzed by transmission electron microscopy combined with focused ion beam technology. To measure the thermal conductivity of gallium-based TIM filled with chromium-coated diamond particles, a specific three-layer structure sample is made for laser flash analysis and the corresponding theoretical fitting model is deduced subsequently. After performing iterative solution through programming, our results present that 47 wt% addition of chromium-coated diamond particles can dramatically increase the thermal conductivity of pure gallium from 29.3 to 112.5 W/(m·K) at room temperature. And fortunately, it has not yet been observed that the chromium coating is over consumed by liquid metal or the thermal conductivity of composite seriously degrades after thermal aging treatment at 80 °C for 192 h, strongly indicating that chromium could be used as the diffusion barrier layer for heat-conducting particles and the metal substrates to maintain long-term reliable service of gallium-based TIMs.
TL;DR: In this article, focused ion beam (FIB) equipped on the scanning electron microscope (SEM) was used to mill a large crystal to thin lamella, and the influences of the milling on the crystal lamella were observed and investigated.
TL;DR: In this paper, a well-defined core-shell structure for pitting corrosion products was revealed by using a combination of dual-beam focused ion beam system with scanning electron microscope (FIB/SEM) and high-resolution transmission electron microscopy (HRTEM).
TL;DR: In this paper, the microstructural evolution of micrometer-sized single tin particle was monitored by focused ion beam polishing and scanning electron microscopy (SEM) imaging during electrochemical cycling by in situ FIB-SEM.
Abstract: Tin (Sn) is a potential anode material for highenergy density Li-ion batteries because of its high capacity, safety, abundance and low cost. However, Sn suffers from large volume change during cycling, leading to fast degradation of the electrode. For the first time, the microstructural evolution of micrometer-sized single Sn particle was monitored by focused-ion beam (FIB) polishing and scanning electron microscopy (SEM) imaging during electrochemical cycling by in situ FIB-SEM. Our results show the formation and evolution of cracks during lithiation, evolution of porous structure during delithiation and volume expansion/contraction during cycling. The electrochemical performance and the microstructural evolution of the Sn microparticle during cycling are directly correlated, which provides insights for understanding Sn-based electrode materials.
TL;DR: In this article, the authors present a review of the secondary ion mass spectrometer (SIMS) and focused ion beam (FIBSEM) for 3D chemical analysis with high lateral resolution.
TL;DR: In this paper, the formation mechanism of pores was analyzed and the effects of laser power, feeding rate, scanning speed and ultrasonic power on pores were investigated for sample microstructure and phase composition, and the relative density of samples was measured by the progressive focused ion beam and the porosity was calculated by image processing software Image.
Abstract: Pores are common defects in the process of directed laser deposition (DLD) which not only greatly reduce the fracture toughness of ceramic materials, but also lead to the failure of shaped parts. In this paper, the formation mechanism of pores was analyzed and the effects of laser power, feeding rate, scanning speed and ultrasonic power on pores were investigated. Transmission electron microscope, scanning electron microscopy observation and X-ray diffraction analysis were carried out for sample microstructure and phase composition respectively. The relative density of samples was measured by the progressive focused ion beam and the porosity was calculated by image processing software Image. The results show that the pores are divided into gas holes and shrinkage cavities. The appearance of circular gas holes with smooth inner walls are caused by the feeding method by gas forced blowing, the gas mixed with powder itself, and the gas in the molten pool formed by gasification of low-melting impurities and alumina/zirconia during laser processing. The gas holes are evenly distributed in the cross-section of the thin-walled specimen parallel to the scanning speed. As the temperature changes drastically, the material around the melt solidifies first, the melt will be attached to the solidified material to shrink, so that the melt can not be filled as a solid and finally the shrinkage cavities are formed. Generally the shrinkage cavities are irregular and the pore wall is relatively rough, mainly concentrated on the top of thin-walled samples. The laser power has the greatest influence on the pores, which has the greatest effect on the porosity but little effect on the shrinkage cavities. After attaching the ultrasound, the gas holes are mainly distributed on the top of the sample, and the shrinkage cavities almost disappear due to acoustic streaming effect of ultrasonic. When the ultrasonic power is 180 W, the porosity reaches a minimum of 0.1±0.05% and the relative density is 99.9±0.1%.
TL;DR: It is shown that spectral features of a plasmonic STM junction can be manipulated by nanofabrication of Au tips using focused ion beam, paving the way for near-field imaging and spectroscopy with a high degree of accuracy.
Abstract: Near-field manipulation in plasmonic nanocavities can provide various applications in nanoscale science and technology. In particular, a gap plasmon in a scanning tunneling microscope (STM) junction is of key interest to nanoscale imaging and spectroscopy. Here we show that spectral features of a plasmonic STM junction can be manipulated by nanofabrication of Au tips using focused ion beam. An exemplary Fabry-Perot type resonator of surface plasmons is demonstrated by producing the tip with a single groove on its shaft. Scanning tunneling luminescence spectra of the Fabry-Perot tips exhibit spectral modulation resulting from interference between localized and propagating surface plasmon modes. In addition, the quality factor of the plasmonic Fabry-Perot interference can be improved by optimizing the overall tip shape. Our approach paves the way for near-field imaging and spectroscopy with a high degree of accuracy.
TL;DR: It is revealed that the photoluminescence intensity from ILHPs can be modulated by more than 1 order of magnitude upon low-dose gallium ion irradiation, which can be attributed to the generation of vacancy/interstitial defects, metallic lead, and crystal-to-amorphization transition.
Abstract: Achieving controllable coherent and incoherent light sources is crucial to meet the requests of the constantly developing integrated optics, which, however, remains challenging for the existing semiconductor materials and techniques. All-inorganic lead halide perovskites (ILHPs) are emerging as the promising semiconductors, featuring the defect-tolerant nature and tunable band gap. Herein, an experimental design, based on the interaction between ILHPs and energetic ions, for achieving controllable light emitters and microlasers is reported. We reveal that the photoluminescence intensity from ILHPs can be modulated by more than 1 order of magnitude upon low-dose gallium ion (∼1015 ions/cm2) irradiation, which can be attributed to the generation of vacancy/interstitial defects, metallic lead, and crystal-to-amorphization transition. Such ion-dependent light emission can be exploited to make the colorful photopatterns and in situ tailor the lasing behavior from CsPbBr3 microplates. Further, a strong sputtering effect is observed with the increase of the ion dose (∼1017 ions/cm2), which enables the top-down fabrication of microlasers based on ILHPs. These findings represent a significant step toward controllable light sources leveraging on perovskite-ion interactions.
TL;DR: In this article, PEO coatings were prepared on an Al-Cu-Li alloy in a mixed electrolyte of silicate and tungstate, and the coatings are characterized by a series of advanced analysis methods.
Abstract: Detailed characterization of W species and amorphous material in plasma electrolytic oxidation (PEO) coatings formed in W-containing electrolyte is important to PEO study. In this paper, PEO coatings were prepared on an Al-Cu-Li alloy in a mixed electrolyte of silicate and tungstate, and the coatings were characterized by a series of advanced analysis methods. Scanning electron microscopy (SEM) shows that PEO leads to a bi-layered coating with big internal pores and the W element was enriched close to the coating/substrate interface. X-ray photoelectron spectroscopy (XPS) shows that hexavalent tungsten is the predominant species; however, weak peaks for free-state W have been found in the inner coating exposed by grinding. Focused ion beam (FIB) was used to prepare an electron-transparent sample across the coating/substrate interface for the transmission electron microscopy (TEM) characterization. TEM results show that free-state W exists in the form of nanocrystalline particles, while the amorphous material was found surrounding the large internal pores of the coating. The amorphous material consists of O, Al, W, Si and Cu, and the elements other than O have comparable atomic percentages. According to models proposed in this paper, the nanocrystalline W particles were formed by the thermite reaction between fine molten Al drops and tungsten oxides. However, amorphous material was formed due to its complex composition and the rapid cooling rate brought from the ingress of electrolyte into the big pores.
TL;DR: Electrical measurements indicate that W-C layers and nanowires grown by Cryo-FIBID exhibit metallic resistivity, which pave the way for the use of Cryo, FIBID in various applications in micro- and nano-lithography such as circuit editing, photomask repair, hard masks, and the growth of nanowire and contacts.
Abstract: An ultra-fast method to directly grow metallic micro- and nano-structures is introduced. It relies on a Focused Ion Beam (FIB) and a condensed layer of suitable precursor material formed on the substrate under cryogenic conditions. The technique implies cooling the substrate below the condensation temperature of the gaseous precursor material, subsequently irradiating with ions according to the wanted pattern, and posteriorly heating the substrate above the condensation temperature. Here, using W(CO)6 as the precursor material, a Ga+ FIB, and a substrate temperature of −100 °C, W-C metallic layers and nanowires with resolution down to 38 nm have been grown by Cryogenic Focused Ion Beam Induced Deposition (Cryo-FIBID). The most important advantages of Cryo-FIBID are the fast growth rate (about 600 times higher than conventional FIBID with the precursor material in gas phase) and the low ion irradiation dose required (∼50 μC/cm2), which gives rise to very low Ga concentrations in the grown material and in the substrate (≤0.2%). Electrical measurements indicate that W-C layers and nanowires grown by Cryo-FIBID exhibit metallic resistivity. These features pave the way for the use of Cryo-FIBID in various applications in micro- and nano-lithography such as circuit editing, photomask repair, hard masks, and the growth of nanowires and contacts. As a proof of concept, we show the use of Cryo-FIBID to grow metallic contacts on a Pt-C nanowire and investigate its transport properties. The contacts have been grown in less than one minute, which is considerably faster than the time needed to grow the same contacts with conventional FIBID, around 10 hours.
TL;DR: The comparison indicates that Cryo-FIBID is very competitive and shows great potential for future lithography developments, and the comparison of these techniques with other charge-based lithography techniques in terms of the charge dose required and process complexity.
Abstract: In this contribution, we compare the performance of Focused Electron Beam-induced Deposition (FEBID) and Focused Ion Beam-induced Deposition (FIBID) at room temperature and under cryogenic conditions (the prefix "Cryo" is used here for cryogenic). Under cryogenic conditions, the precursor material condensates on the substrate, forming a layer that is several nm thick. Its subsequent exposure to a focused electron or ion beam and posterior heating to 50 °C reveals the deposit. Due to the extremely low charge dose required, Cryo-FEBID and Cryo-FIBID are found to excel in terms of growth rate, which is typically a few hundred/thousand times higher than room-temperature deposition. Cryo-FIBID using the W(CO)6 precursor has demonstrated the growth of metallic deposits, with resistivity not far from the corresponding deposits grown at room temperature. This paves the way for its application in circuit edit and the fast and direct growth of micro/nano-electrical contacts with decreased ion damage. The last part of the contribution is dedicated to the comparison of these techniques with other charge-based lithography techniques in terms of the charge dose required and process complexity. The comparison indicates that Cryo-FIBID is very competitive and shows great potential for future lithography developments.
TL;DR: While gallium and neon ion milling result in the implantation of ions up to tens of nanometers from the milled edge and local thinning near the edge, helium ions milling produces much sharper edges with dramatically reduced implantation.
Abstract: Focused ion beam milling of ∼200 nm polymer thin films is investigated using a multibeam ion microscope equipped with a gallium liquid metal ion source and a helium/neon gas field-ionization source. The quality of gallium, neon, and helium ion milled edges in terms of ion implantation artifacts is analyzed using a combination of helium ion microscopy, transmission electron microscopy and light microscopy. Results for a synthetic polymer thin film, in the form of cryo-ultramicrotomed sections from a co-extruded polymer multilayer, and a biological polymer thin film, in the form of the base layer of a butterfly wing scale, are presented. While gallium and neon ion milling result in the implantation of ions up to tens of nanometers from the milled edge and local thinning near the edge, helium ion milling produces much sharper edges with dramatically reduced implantation. These effects can be understood in terms of the minimal lateral scatter and larger stopping distance of helium compared with the heavier ions, whereby due to the thin film geometry, most of the incident helium ions will pass straight through the material. The basic result demonstrated here for polymer thin films is also expected for thin films of hard materials such as metals and ceramics.
TL;DR: Solid icosahedra, polyhedral platelets, and rods of hitherto-unreported sizes are demonstrated well below the 3D-printing resolution, in line with the surface-freezing-driven mechanism proposed for the faceting phenomenon.
TL;DR: In this article, an analysis of the tribological performance of laser-induced periodic surface structures (LIPSS) treated X5CrNi1810 stainless steel was conducted, where the approach followed by authors was to generate LIPSS-patterned circular tracks, composed of radial straight grooves with uniform angular periodicity.
Abstract: In this work, an analysis of the tribological performance of laser-induced periodic surface structures (LIPSS) treated X5CrNi1810 stainless steel was conducted. The approach followed by authors was to generate LIPSS-patterned circular tracks, composed of radial straight grooves with uniform angular periodicity. This permitted to measure the tribological properties in a pin-on-flat configuration, keeping fixed the orientation between the grooves and the sliding direction. A Stribeck curve was measured, as well as the consequent wear. A deep analysis of the sub-surface conditions after LIPSS generation was moreover performed using Focused Ion Beam (FIB) cross-section.
TL;DR: In this article, the authors demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport, which can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material.
Abstract: Geometric electron optics may be implemented in solid state when transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport. We probe this directional ballistic regime in a single crystal of PdCoO2 by use of focused ion beam (FIB) micro-machining, defining crystalline ballistic circuits with features as small as 250nm. The peculiar hexagonal Fermi surface naturally leads to electron self-focusing effects in a magnetic field, well below the geometric limit associated with a circular Fermi surface. This super-geometric focusing can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material. These results suggest a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermi surfaces.
TL;DR: In this article, femtosecond laser cutting has been used to fabricate micro- and mesoscale specimens for mechanical testing, but the impact on mechanical properties has not been fully evaluated.