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The Casimir force, a quantum mechanical effect, has been observed in several microelectromechanical system (MEMS) platforms. Due to its extreme sensitivity to the separation of two objects, the Casimir force has been proposed as an excellent avenue for quantum metrology. Practical application, however, is challenging due to attractive forces leading to stiction and device failure, called Casimir pull-in. In this work, we design and simulate a Casimir-driven metrology platform, where a time-delay-based parametric amplification technique is developed to achieve a steady-state and avoid pull-in. We apply the design to the detection of weak, low-frequency, gradient magnetic fields similar to those emanating from ionic currents in the heart and brain. Simulation parameters are selected from recent experimental platforms developed for Casimir metrology and magnetic gradiometry, both on MEMS platforms. While a MEMS offers many advantages to such an application, the detected signal must typically be at the resonant frequency of the device, with diminished sensitivity in the low frequency regime of biomagnetic fields. Using a Casimir-driven parametric amplifier, we report a 10,000-fold improvement in the best-case resolution of MEMS single-point gradiometers, with a maximum sensitivity of 6 Hz/(pT/cm) at 1 Hz. Further development of the proposed design has the potential to revolutionize metrology and may specifically enable the unshielded monitoring of biomagnetic fields in ambient conditions.

International audience; Time-effective, unsupervised clustering techniques are exploited to discriminate nanometric metal disks patterned on a dielectric substrate. The discrimination relies on cluster analysis applied to time-resolved optical traces obtained from thermo-acoustic microscopy based on asynchronous optical sampling. The analysis aims to recognize similarities among nanopatterned disks and to cluster them accordingly. Each cluster is characterized by a fingerprint time-resolved trace, synthesizing the common features of the thermo-acoustics response of the composing elements. The protocol is robust and widely applicable, not relying on any specific knowledge of the physical mechanisms involved. The present route constitutes an alternative diagnostic tool for on-chip non-destructive testing of individual nano-objects.

This review aims to focus on the most recent advances and applications of carbon dots (CDs) in the fields of bioanalytical research and clinical analysis involving separation techniques. It includes both facets of the analytical nanoscience and nanotechnology as it is applying analytical nanometrology for CDs and their proper use as tools in (bio)analytical processes. With this purpose, the main properties of carbon dots and the basic synthetic strategies of these materials are summarized, together with the main techniques used for CDs characterization, including the use of separation approaches to describe some of their unique properties. Furthermore, recent and potential further applications and the prospective utilization of these nanomaterials, together with analytical separation techniques, are also discussed.

We investigate the anti-Stokes Raman scattering of single carbyne chains confined inside double-walled carbon nanotubes. Individual chains are identified using tip-enhanced Raman scattering (TERS) and heated by resonant excitation with varying laser powers. We study the temperature dependence of carbyne’s Raman spectrum and quantify the laser-induced heating based on the anti-Stokes/Stokes ratio. Due to its molecular size and its large Raman cross section, carbyne holds great promise for local temperature monitoring, with potential applications ranging from nanoelectronics to biology., ACS Nano, 15 (7), ISSN:1936-0851, ISSN:1936-086X

Extracellular Vesicles (EVs) are heterogeneous vesicular structures ranging in size from 50 to 5000 nm. They are released by all types of cells and difficult to distinguish due to their heterogeneity, the overlap of their physical properties with other components of complex media such as protein aggregates, lipoproteins, etc.The NanoBioAnalytical (NBA) platform was developed as a multiplexed analytical solution for efficient and label-free characterization of EVs. It is a multi-bio-physical characterization technique composed of Surface Plasmon Resonance imaging (SPRi), Atomic Force Microscopy (AFM) and Mass Spectrometry (MS).The first axis of this work consisted in evaluating the analytical performance of the NBA platform for a complex biological sample of EVs, derived from platelets (PEV) provided by Taipei Medical University (TMU). A biochip specific multiplex format was designed using antibodies against the CD41 protein commonly expressed in PEVs. EVs are immunocaptured by an antibody biochip grafted at two different concentrations. PEVs are tested over a concentration range spanning 4 decades, followed by in situ nanocharacterization by AFM in order to study their structural and morphological characteristics. The quantitative analysis of EVs is also carried out by counting EVs, as well as by a detailed metrological analysis. An improved data analysis method has also been developed for processing and analyzing SPRi and AFM data. A dynamic threshold selection method was studied to optimize AFM quantification parameters. The results demonstrated that the platform could be sensitive to a concentration of 10^6 EV / mL without any signal amplification strategy. It is also shown that the NBA platform exhibits a linear dynamic range over at least 3 orders of magnitude (10^6-10^9 PEV / mL).The second part of the work concerns the characterization of EVs in various preparations of human platelet lysates (HPL) studied for their role in neuroprotection. Three preparations, of Platelet Pellet Lysates (PPL), Heat-treated (HPPL), or Serum converted (SCPL) were obtained from TMU. Different HPL preparations have been shown to be neuroprotective against cell toxicity in vitro and Parkinson's disease as well as in Traumatic Brain Injury (TBI) models in vivo. The objective of this section is to qualify EVs in these three types of products. A multiplexed biochip dedicated to monitoring 7 different markers was designed for the study via the NBA platform. The phenotyping as well as the characterization of the EVs indicated that there is a difference in the expression of the phenotypes and the EVs in these different preparations.This work establishes the ability of the NBA platform to characterize EVs in complex samples without labeling and in multiplex format. The results obtained make it possible to position this platform both in an exploratory approach for research purposes on EVs but also in a theranostic perspective.Finally, we believe that the NBA platform will be able to make a significant contribution in the field of standardization of EV characterization methods. The combination of data generated by the NBA, coupled with its resolving potential, will allow the development of an evaluation grid that is both global and discriminating, because of its specificity to the nature of the EV samples. This proposed metric, called "EVs Consistency Index" (EVCI), will be useful in assessing the purity, vesicular composition (subpopulations), and variability of EV preparations. The envisaged EVCI could contribute to the establishment of international standards for the calibration and characterization of EV preparations., Les vésicules extracellulaires (VE) sont des structures vésiculaires hétérogènes de taille allant de 50 à 5000 nm. Elles sont libérées par tous les types de cellules et difficiles à distinguer en raison de leur hétérogénéité, du chevauchement de leurs propriétés physiques avec d'autres composants de milieux complexes tels que des agrégats protéiques, des lipoprotéines, etc.La plate-forme NanoBioAnalytique (NBA) a été développée en tant que solution analytique multiplexée pour une caractérisation efficace et sans marquage des VE. Il s'agit d'une technique de caractérisation multi-bio-physique composée d'imagerie par résonance plasmonique de surface (SPRi), de microscopie à force atomique (AFM) et de spectrométrie de masse (MS).Le premier axe de ce travail a consisté à évaluer les performances analytiques de la plateforme NBA pour un échantillon biologique complexe de VE, dérivées des plaquettes (PVE) fourni par l’Université Médicale de Taipei (TMU). Un format multiplex spécifique d'une biopuce a été conçu en utilisant des anticorps contre la protéine CD41 couramment exprimée dans les PVE. Les VEs sont immuno-capturées par une biopuce d'anticorps greffés à deux concentrations différentes et sur une plage de concentration couvrant 4 décades, suivi d’une nanocaractérisation in situ par AFM afin d’étudier leurs caractéristiques structurales et morphologiques. L'analyse quantitative des VE est également effectuée par le dénombrement des VEs, ainsi que par une analyse métrologique fine. Une méthode améliorée d'analyse des données a également été développée pour le traitement et l'analyse des données SPRi et AFM. Une méthode de sélection de seuil dynamique a été étudiée pour optimiser les paramètres de quantification de l'AFM. Les résultats ont démontré que la plateforme peut être sensible à une concentration de 106 VE/mL sans aucune stratégie d'amplification du signal. Il est également démontré que la plateforme NBA présente une plage dynamique linéaire sur au moins 3 ordres de grandeur (106-109 PEV/mL).Le deuxième volet du travail porte sur la caractérisation des VE dans diverses préparations de lysats plaquettaires humains (HPL) étudiées pour leur rôle en neuroprotection. Trois préparations, de lysats de plaquettes (PPL), traitées thermiquement (HPPL), ou lysats convertis en sérum (SCPL) ont été obtenues auprès de TMU. Différentes préparations de HPL s’avèrent en effet neuroprotectrices contre la toxicité cellulaire in vitro et la maladie de Parkinson in vivo ainsi que sur des modèles de traumatisme crânien. L'objectif de ce volet est de qualifier les VE dans ces trois types de produits. Une biopuce multiplexée dédiée au suivi de 7 marqueurs différents a été conçue pour l'étude via la plateforme NBA. Le phénotypage ainsi que la caractérisation des VEs ont indiqué qu'il existe une différence dans l'expression des phénotypes et des VEs dans ces différentes préparations.Ce travail permet d’établir la capacité de la plateforme NBA à caractériser les VE au sein d’échantillons complexes sans marquage et en format multiplexe. Les résultats obtenus permettent de positionner cette plateforme à la fois dans une approche exploratoire à des fins de recherche sur les VE mais également dans une perspective théranostique.Enfin, nous considérons que la plateforme NBA pourra apporter une contribution significative dans le domaine de la standardisation des méthodes de caractérisation des VE.La combinaison des données générées par la NBA, couplée à son potentiel résolutif, permettra de développer une grille d’évaluation à la fois globale et discriminante, car spécifique, de la nature des échantillons de VE. Cette métrique proposée, appelée « index cartographique EVs » (EVCI), sera utile pour évaluer la pureté, la composition vésiculaire (sous-populations), et la variabilité des préparations de VE. L'EVCI ainsi envisagée pourrait contribuer à l’établissement de normes internationales pour l'étalonnage et la caractérisation de préparations de VE.

The difficulty of making accurate, repeatable, sub-nanometer displacement measurements has limited the progress of nanotechnology and surface science. Scanning probe microscopy, an important set of tools for characterizing nanoscale structures, is capable of atomic resolution imaging, but has yet to realize its full, metrological potential. This work evaluates the feasibility of using microwave cavities to address this need. Accurate and stable RF frequency references have become ubiquitous and are an attractive option for realizing traceable distance measurements through the resonant frequency of microwave cavities operating in TEM modes. A method of measuring the resonant frequency of such cavities capable of sensing picometer displacements is developed. The concept is demonstrated with a variable-length, 10 GHz coaxial cavity, and proves to have a resolution of 60 fm Hz-1/2, and a range of 10 μm. Independent measurements with an interferometer verify that the device is capable of displacement measurements accurate to 1% without external calibration, and with non-linearity

Hintergrund: Die Entwicklung von Nanotechnologien und insbesondere integrierten Schaltkreisen beruht auf dem Verständnis von Struktur und Funktion auf der Nanoskala, wofür exakte Messungen erforderlich sind. Kleinwinkel-Röntgenstreuung unter streifendem Einfall (GISAXS) ist eine Methode zur schnellen, berührungs- und zerstörungsfreien dimensionellen Messung von nanostrukturierten Oberflächen. Ziele: Es soll die Möglichkeit untersucht werden, die zunehmend komplexeren Proben aus Wissenschaft und Industrie mit Hilfe von GISAXS präzise zu vermessen. Ein weiteres Ziel ist es, Messtargets aus der Halbleiter-Qualitätskontrolle mit einer Größe von ca. 40x40 µm² zu messen, deren Signal typischerweise nicht zugänglich ist, weil ein Bereich von ca. 1x20 mm² auf einmal beleuchtet wird. Methoden: Synchrotron-basierte GISAXS-Messungen verschiedener Proben werden mit Hilfe einer Fourier-Konstruktion, der "distorted wave Born approximation" und einem Maxwell-Gleichungs-Löser basierend auf finiten Elementen analysiert. Ergebnisse: Aus GISAXS-Messungen kann die Linienform von Gittern mit einer Periode von 32 nm rekonstruiert werden und sie weicht weniger als 2 nm von Referenzmessungen ab. Eine sorgfältige Bayes'sche Unsicherheitsanalyse zeigt jedoch, dass wichtige dimensionelle Parameter innerhalb der Unsicherheiten nicht übereinstimmen. Für die Messung von kleinen Gittertargets entwerfe ich ein neuartiges Probendesign, bei dem das Target in Bezug auf die umgebenden Strukturen gedreht wird, und stelle fest, dass dadurch parasitäre Streuung effizient unterdrückt wird. Fazit: GISAXS-Messungen von komplexen Nanostrukturen und kleinen Targets sind möglich, jedoch würde GISAXS enorm von effizienteren Simulationsmethoden profitieren, die alle relevanten Effekte wie Rauhigkeit und Randeffekte einbeziehen. Hier gibt es vielversprechende theoretische Ansätze, so dass GISAXS eine zusätzliche Methode für die Halbleiter-Qualitätskontrolle werden könnte. Background. The development of nanotechnology such as integrated circuits relies on an understanding of structure and function at the nanoscale, for which reliable and exact measurements are needed. Grazing-incidence small angle X-ray scattering (GISAXS) is a versatile method for the fast, contactless and destruction-free measurement of sizes and shapes of nanostructures on surfaces. Aims. A goal of this work is to investigate the possibility of precisely measuring the increasingly complex samples produced in science and industry using GISAXS. A second objective is to measure targets used in semiconductor quality control with a size of approx. 40x40 µm², whose signal is typically not accessible because an area of approx. 1x20 mm² is illuminated at once. Methods. I take synchrotron-based GISAXS measurements and analyze them using reciprocal space construction, the distorted wave born approximation, and a solver for Maxwell's equations based on finite elements. Results. I find that the line shape of gratings with a period of 32 nm can be reconstructed from GISAXS measurements and the results deviate less than 2 nm from reference measurements; however, a careful Bayesian uncertainty analysis shows that key dimensional parameters do not agree within the uncertainties. For the measurement of small grating targets, I create a novel sample design where the target is rotated with respect to the surrounding structures and find that this efficiently suppresses parasitic scattering. Conclusions. I show that GISAXS measurements of complex nanostructures and small targets are possible, and I highlight that further development of GISAXS would benefit tremendously from efficient simulation methods which describe all relevant effects such as roughness and edge effects. Promising theoretical approaches exist, so that GISAXS has the potential to become an additional method in the toolkit of semiconductor quality control.

One dimensional (1D) Cr nanograting fabricated by laser-focused atomic deposition (LFAD) is suitable for reference materials in nanometrology, owing to its self-traceable to SI meter definition and high accuracy with good uniformity. For further preparing small-scale and traceable reference materials, extremely ultraviolet (EUV) interference lithography with 13.4nm wavelength is utilized to accurately shorten the grating pitch of Cr nanograting (212.8nm). Diffraction efficiency is a key attribute in EUV interference lithography. In this paper, based on rigorous coupled wave analysis (RCWA), diffraction efficiency with EUV light of Cr nanograting was studied. Impacts such as EUV light wavelength, background layer and grating height were mainly taken into consideration. The result shows that Cr background layer has significant influence on diffraction efficiency of Cr nanograting, and an optimized diffraction efficiency of the first diffraction order about 1.4% has been achieved under the practical experimental condition.

The development of semiconductor industry has made nanometrology more and more important, of which Si/SiO2 multilayer thin-film based critical dimension structures is one of the potential certified reference materials to calibrate measurement instruments. However, in the fabrication process, the quality of the bonding step mainly influences the performance of final structures. In this study, we applied thermocompression bonding method to eliminate the side effect, such as the contamination of adhesive layer and the influence of the adhesive layer on AFM probes caused by the traditional adhesive bonding. Further, thermocompression bonding realized simultaneous observation on both left and right structures in different wafers. On this basis, we also discussed the influence of the size of the silicon wafer, bonding temperature and pressure on bonding performance. The images show that small size is more conducive to improve bonding quality. Besides, the AFM measurement results indicate that Si/SiO2 multilayer thin-film can remain undeformed under higher temperature and pressure (200°C-300°C, 0.6MPa-1.0MPa). This method provides support for Si/SiO2 multilayer thin-film based critical dimension to become high quality certified reference material.

Hierarchical micro-nanostructured surfaces are key components of ‘smart’ multifunctional materials, used to control wetting, adhesion, tactile, friction, optical, antifogging, antibacterial, and many more surface properties. Hierarchical surfaces comprise random or ordered structures ranked by their length scale spanning the range from a few nanometers to a few micrometers, with the larger microstructures typically embedding smaller nanostructures. Despite the importance of hierarchical surfaces, there have been few studies on their precise and controlled fabrication or their quantitative characterization, and they usually involve multiple and complex fabrication steps. Here, we present a new plasma nanotechnology, which we term ‘nanoinhibit’, and a new plasma reactor for producing in one facile process-step-controlled hierarchy at will on polymeric surfaces. We couple the new plasma nanotechnology with detailed computational nanometrology based on the analysis of scanning electron microscopy images and targeted to specific functionality. We showcase the potential of ‘nanoinhibit’ for functional surface fabrication by controlling the wetting and optical functionality of the fabricated hierarchical surfaces and showing its dependence on surface morphology metrics. Finally, we observe that ‘nanoinhibit’ produces a new class of ‘strong hierarchical’ surfaces exhibiting spatially separated periodic and fractal-like components.

In this study, we propose a novel plate-like sensor which utilizes curvature-based stiffening effects for enhanced nanometrology. In the proposed concept, the stiffness and natural frequencies of the sensor can be arbitrarily adjusted by applying a transverse curvature via piezoelectric actuators, thereby enabling resonance amplification over a broad range of frequencies. The concept is validated using a macroscale experiment. Then, a microscale finite element analysis is used to study the effect of applied curvature on the microplate static stiffness and natural frequencies. We show that imposed transverse curvature is an effective way to tune the in-situ static stiffness and natural frequencies of the plate sensor system. These findings will form the basis of future curvature-based stiffening microscale studies for novel scenarios in atomic force microscopy.

In this work we present a comparison exercise between two metrological institutes for size measurement of silica nanoparticles by Asymmetrical Flow Field-Flow Fractionation (AF4) coupled to static light scattering. The work has been performed in the frame of a French inter-laboratory comparison (ILC) exercise organized by the nanoMetrology Club (CnM). The general aim of this multi-technique comparison was to improve the measurement process for each technique, after establishing a well-defined measurement procedure. The results obtained by two national metrological institutes (NMIs), the LNE (France) and the SMD (Belgium) by AF4-UV-DRI-MALS will be presented and discussed. Three different samples were characterized: the reference material ERM®-FD304, which is a suspension of colloidal silica in aqueous solution and two silica bimodal samples consisting of two populations of SiO2 nanoparticles of unknown size in aqueous solution, with different populations’ ratios. The procedure for the preparation of the sample before the analysis, and main separation parameters have been previously defined between the two institutes and will be described. The principals measured parameters were the weight-average (dge_w), number-average (dge_n) and z-average (dge_z) geometric diameter; the average hydrodynamic diameter (dh); and the diameter obtained by external calibration using polystyrene latex standards (dcal). Results between the two NMIs were comparable and coherent with the expected size values of those obtained by other techniques like Scanning Mobility Particle Sizer (SMPS) and Scanning Electron Microscopy (SEM) also involved in this ILC exercise. Where discrepancies are observed, they leave the results compatible within their uncertainties and underpin the challenges in analysing data and reporting results, making AF4 a powerful tool to compare to other measurement techniques.

Surface roughness plays an important role in various fields of nanoscience and nanotechnology. However, the present practices in roughness measurements, typically based on some Atomic Force Microscopy measurements for nanometric roughness or optical or mechanical profilometry for larger scale roughness significantly bias the results. Such biased values are present in nearly all the papers dealing with surface parameters, in the areas of nanotechnology, thin films or material science. Surface roughness, most typically root mean square value of irregularities Sq is often used parameter that is used to control the technologies or to link the surface properties with other material functionality. The error in estimated values depends on the ratio between scan size and roughness correlation length and on the way how the data are processed and can easily be larger than 10% without us noting anything suspicious. Here we present a survey of how large is the problem, detailed analysis of its nature and suggest methods to predict the error in roughness measurements and possibly to correct them. We also present a guidance for choosing suitable scan area during the measurement.

A new and exciting imaging technique being applied to thin films, nanocoatings, nanogels, and nanoparticle analysis is ultra-low accelerating voltage or ultra-low-landing-energy scanning electron microscopy (ULVSEM). Instrument conditions in this mode are different than with typical SEM observation or contemporary low accelerating voltage (LVSEM) imaging. Hence, the images appear far different due to reduced beam penetration. The landing energy of the primary electron beam can be much lower than LVSEM, it can be reduced to far below 500 electron volts (eV), even as low as 10 eV. Thus, the electron beam range and penetration are reduced tremendously with some unavoidable loss of spatial resolution. Surface details are enhanced, contrast might favorably change, and secondary electron (SE) edge enhancement or “blooming” contributing to measurement uncertainty is greatly reduced, potentially allowing for more precise and new measurements once this imaging mode is fully characterized and accurately modeled. High-resolution field-emission electron sources, improved lens, detector designs, and sample biasing all contribute to the ability to image at such low electron landing energies. The techniques of ULVSEM are discussed, and an application example is presented.

Magnetic sensing is present in our everyday interactions with consumer electronics and demonstrates the potential for the measurement of extremely weak biomagnetic fields, such as those of the heart and brain. In this work, we leverage the many benefits of microelectromechanical system (MEMS) devices to fabricate a small, low-power, and inexpensive sensor whose resolution is in the range of biomagnetic fields. At present, biomagnetic fields are measured only by expensive mechanisms such as optical pumping and superconducting quantum interference devices (SQUIDs), suggesting a large opportunity for MEMS technology in this work. The prototype fabrication is achieved by assembling micro-objects, including a permanent micromagnet, onto a postrelease commercial MEMS accelerometer using a pick-and-place technique. With this system, we demonstrate a room-temperature MEMS magnetic gradiometer. In air, the sensor’s response is linear, with a resolution of 1.1 nT cm−1, spans over 3 decades of dynamic range to 4.6 µT cm−1, and is capable of off-resonance measurements at low frequencies. In a 1 mTorr vacuum with 20 dB magnetic shielding, the sensor achieves a 100 pT cm−1 resolution at resonance. This resolution represents a 30-fold improvement compared with that of MEMS magnetometer technology and a 1000-fold improvement compared with that of MEMS gradiometer technology. The sensor is capable of a small spatial resolution with a magnetic sensing element of 0.25 mm along its sensitive axis, a >4-fold improvement compared with that of MEMS gradiometer technology. The calculated noise floor of this platform is 110 fT cm−1 Hz−1/2, and thus, these devices hold promise for both magnetocardiography (MCG) and magnetoencephalography (MEG) applications. A small, low-power, inexpensive magnetic sensor has been developed in a commercially available platform with a resolution that is within the range of biomagnetic fields. Magnetic sensing is applied in everyday interactions with consumer electronics (such as for navigation) and has the potential to measure extremely weak biomagnetic fields (such as those of the heart and brain). Hitherto, biomagnetic fields have been measured only using expensive mechanisms. However, a team headed by Josh Javor at Boston University, USA has succeeded in applying the benefits of micro-electromechanical systems to fabricate a low-cost magnetic sensor in a small, versatile platform that can be easily integrated into consumer technology. We believe that their new technology has the potential to revolutionize magnetic sensing and offer considerable advantages in such areas as navigation, communication, and biomagnetic field mapping.

International audience; An intercomparison campaign on nanoparticle size measurement was organized in the frame of the French nanoMetrology club. The aim of this study is to make an inventory of the metrological capabilities of all measurement techniques in France involved in the “nano” size range, including the SMPS (Scanning Mobility Particle Sizer) concerning aerosol metrology. For this study, four samples have been proposed, namely (1) - a SiO2 colloidal suspension (FD304) consisting of a monomodal population, (2) - two samples consisting of two nanoparticle populations of SiO2 having proportions to be determined and (3) - a TiO2 colloidal suspension. Ten SMPS associated to five participants around a common experimental setup were performed in link with a control SMPS to have simultaneous measurements with a same instrument in each laboratory in parallel with the SMPS used by each partner. This article presents SMPS results of this study associated with the description of the experimental set-up and the sample preparation protocol with an identified schedule and comparison with SEM measurements. The present paper does not focus on the actual capability of the tested mobility spectrometers, but aims to highlights the good laboratory practices using their own but common resources in terms of aerosol generation and measurement set-ups.

Laser-driven light sources (LDLS) have ultrahigh-brightness and broad wavelength range. They are ideal radiation sources for optical metrology tools for advanced process control in semiconductor manufacturing. LDLS sources, with their advantages of 170 nm to 2100 nm wavelength range, have been widely adopted and are being used in volume manufacturing for spectroscopic ellipsometry (SE), spectroscopic scatterometry (SS), and white light interferometry (WLI) applications. Such applications are used to measure critical dimensions (CD), overlay (OVL), and film thickness.

Heat treatment is a green, environmentally friendly and mild pyrolysis process that improves the dimensional stability and durability of wood. In this study, Larix spp. Samples were heated at 180 °C and 210 °C for 6 h with nitrogen, air or oil as heat-conducting media. The influence of high-temperature heat treatment on the microstructure, chemical components, and micromechanical properties was investigated. The mass loss rate increased with increasing temperature, and the degradation of wood components resulted in cracks in the cell walls. Samples treated with air showed more cracks in cell walls than were observed in the cells walls of wood treated with the other heat-conducting media. The hardness of the cell walls increased after all heat treatments. In addition, the results showed that heat treatment reduced creep behavior compared to that of untreated wood.

Scanning probe microscopy (SPM) techniques are amongst the most important and versatile experimental methods in surface- and nanoscience. Although their measurement principles on rigid surfaces are well understood and steady progress on the instrumentation has been made, SPM imaging on suspended, flexible membranes remains difficult to interpret. Due to the interaction between the SPM tip and the flexible membrane, morphological changes caused by the tip can lead to deformations of the membrane during scanning and hence significantly influence measurement results. On the other hand, gaining control over such modifications can allow to explore unknown physical properties and functionalities of such membranes. Here, we demonstrate new types of measurements that become possible with two SPM instruments (atomic force microscopy, AFM, and scanning tunneling microscopy, STM) that are situated on opposite sides of a suspended two-dimensional (2D) material membrane and thus allow to bring both SPM tips arbitrarily close to each other. One of the probes is held stationary on one point of the membrane, within the scan area of the other probe, while the other probe is scanned. This way new imaging modes can be obtained by recording a signal on the stationary probe as a function of the position of the other tip. The first example, which we term electrical cross-talk imaging (ECT), shows the possibility of performing electrical measurements across the membrane, potentially in combination with control over the forces applied to the membrane. Using ECT, we measure the deformation of the 2D membrane around the indentation from the AFM tip. In the second example, which we term mechanical cross-talk imaging (MCT), we disentangle the mechanical influence of a scanning probe tip (e.g. AFM) on a freestanding membrane by means of independently recording the response of the opposing tip. In this way we are able to separate the tip-induced membrane deformation topography from the (material-dependent) force between the tip and the membrane. Overall, the results indicate that probing simultaneously both surfaces of ultra-thin membranes, such as suspended 2D materials, could provide novel insights into the electronic properties of the materials.

The semiconductor industry continues to produce ever smaller devices that are ever more complex in shape and contain ever more types of materials. The ultimate sizes and functionality of these new devices will be affected by fundamental and engineering limits such as heat dissipation, carrier mobility and fault tolerance thresholds. At present, it is unclear which are the best measurement methods needed to evaluate the nanometre-scale features of such devices and how the fundamental limits will affect the required metrology. Here, we review state-of-the-art dimensional metrology methods for integrated circuits, considering the advantages, limitations and potential improvements of the various approaches. We describe how integrated circuit device design and industry requirements will affect lithography options and consequently metrology requirements. We also discuss potentially powerful emerging technologies and highlight measurement problems that at present have no obvious solution.

DNA nanotechnology provides a versatile toolbox for creating custom and accurate shapes that can serve as versatile templates for nanopatterning. These DNA templates can be used as molecular-scale precision tools in, for example, biosensing, nanometrology, and super-resolution imaging, and biocompatible scaffolds for arranging other nano-objects, for example, for drug delivery applications and molecular electronics. Recently, increasing attention has been paid to their potent use in nanophotonics since these modular templates allow a wide range of plasmonic and photonic ensembles ranging from DNA-directed nanoparticle and fluorophore arrays to entirely metallic nanostructures. This Feature Article focuses on the DNA-origami-based nanophotonics and plasmonics - especially on the methods that take advantage of various substrates and interfaces for the foreseen applications.

The present work proposes a novel capacitive absolute positioning sensor based on time grating. The sensor includes a fine incremental-displacement measurement component combined with a coarse absolute-position measurement component to obtain high-resolution absolute positioning measurements. A single row type sensor was proposed to achieve fine displacement measurement, which combines the two electrode rows of a previously proposed double-row type capacitive displacement sensor based on time grating into a single row. To achieve absolute positioning measurement, the coarse measurement component is designed as a single-row type displacement sensor employing a single spatial period over the entire measurement range. In addition, this component employs a rectangular induction electrode and four groups of orthogonal discrete excitation electrodes with half-sinusoidal envelope shapes, which were formed by alternately extending the rectangular electrodes of the fine measurement component. The fine and coarse measurement components are tightly integrated to form a compact absolute positioning sensor. A prototype sensor was manufactured using printed circuit board technology for testing and optimization of the design in conjunction with simulations. Experimental results show that the prototype sensor achieves a ±300 nm measurement accuracy with a 1 nm resolution over a displacement range of 200 mm when employing error compensation. The proposed sensor is an excellent alternative to presently available long-range absolute nanometrology sensors owing to its low cost, simple structure, and ease of manufacturing.