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The effect of carbon coating on a surface structure of a high-dose implanted/annealed silicon carbide (SiC) during annealing was examined using scanning probe microscopy (SPM), deep-ultraviolet (DUV) Raman spectroscopy, and transmission electron microscopy (TEM). In SPM, the surfaces of 500- and 30 °C-implanted/annealed SiC samples without coating exhibited a periodic-step structure and granular structure, respectively. The difference between these surfaces is attributed to the absence or presence of residual implantation damage. In contrast, surface flatness was maintained in the 500 °C-implanted/annealed SiC sample with carbon coating. However, the surface of the coated 30 °C-implanted/annealed SiC sample exhibited a geometric structure with a lattice pattern parallel to the ⟨ 11 2 ¯ 0 ⟩ axes. The DUV Raman spectra and TEM images indicated that the implanted layer of this sample metamorphosed into a mixture of 3C-SiC twin domains and amorphous-SiC regions. During the cooling process after annealing, the 3C-SiC region was more raised than the amorphous-SiC region owing to the difference in the thermal expansion coefficients, thus resulting in the generation of a geometric surface structure. In the metamorphosed implanted layer, the carbon coating does not completely prevent surface roughening. [ABSTRACT FROM AUTHOR]

The current focus in Autonomous Experimentation (AE) is on developing robust workflows to conduct the AE effectively. This entails the need for well-defined approaches to guide the AE process, including strategies for hyperparameter tuning and high-level human interventions within the workflow loop. This paper presents a comprehensive analysis of the influence of initial experimental conditions and in-loop interventions on the learning dynamics of Deep Kernel Learning (DKL) within the realm of AE in scanning probe microscopy. We explore the concept of the "seed effect," where the initial experiment setup has a substantial impact on the subsequent learning trajectory. Additionally, we introduce an approach of the seed point interventions in AE allowing the operator to influence the exploration process. Using a dataset from Piezoresponse Force Microscopy on PbTiO3 thin films, we illustrate the impact of the "seed effect" and in-loop seed interventions on the effectiveness of DKL in predicting material properties. The study highlights the importance of initial choices and adaptive interventions in optimizing learning rates and enhancing the efficiency of automated material characterization. This work offers valuable insights into designing more robust and effective AE workflows in microscopy with potential applications across various characterization techniques. [ABSTRACT FROM AUTHOR]

Cantilever-free scanning probe microscopy has enormous potential for high-throughput topography imaging using parallel probe arrays. However, the current imaging mechanism of the cantilever-free tip architecture hardly considers the efficiency of the detection method regarding precision and bandwidth, which could be a bottleneck to expanding the application of this measurement system. In this communication, we present a contact resistance-based cantilever-free imaging system using radio frequency (RF) reflectometry. RF reflectometry measurements provide sensitive detection of the contact resistance with a wide bandwidth, enabling sub-micrometer-scale topography imaging. We demonstrated our imaging system using a carbon black-polydimethylsiloxane composite tip with a custom-built RF reflectometry setup. The proof-of-concept system achieved a resolution of 230 nm and a bandwidth of the detection system of approximately 8.5 MHz, validating the feasibility of the imaging technique for potential high-throughput cantilever-free scanning probe microscopy. [ABSTRACT FROM AUTHOR]

In contact mode scanning probe microscopy (SPM), the microcantilever probe's dynamics are governed by the (short-range) surface interaction forces, where the tip is "always-in-contact" with the sample. In intermittent contact modes such as "tapping" or bimodal SPM, on the other hand, these are governed by the frequency of the microcantilever's own external excitation. However, when contact mode is employed with high scan speeds (for "video-rate" SPM), we see intermittent transitions—within a single oscillation cycle—between the "always-in-contact" regime and another which is dominated by the microcantilever's inertia. We find—through experiments and physical modeling—that the fast in-plane motion of the sample relative to the probe results in a high surface excitation frequency v / λ (and its harmonics), which excite the microcantilever's out-of-plane eigenmodes and cause it to "break free" of the surface and "overshoot" and "parachute." The impacts of the tip that consequently occur upon the sample inject energy over a wide frequency band into the higher eigenmodes, especially when operating in a low dissipation ambient environment. The microcantilever, then, exhibits phenomena such as eigenmode switching, sidebands, and fractional and combination resonances; such behavior is not seen in, say, tapping mode SPM, since, there, energy is injected at an externally-determined temporal rate. This article investigates the transition from the dynamics of the microcantilever at low speeds to that exhibited at high speeds. The model for dynamic contact loss is validated against the experiments and can be used to propose mitigation of such dynamics in order to achieve high-resolution imaging. [ABSTRACT FROM AUTHOR]

We introduce a new scanning probe microscopy (SPM) concept called reverse tip sample scanning probe microscopy (RTS SPM), where the tip and sample positions are reversed as compared to traditional SPM. The main benefit of RTS SPM over the standard SPM configuration is that it allows for simple and fast tip changes. This overcomes two major limitations of SPM which are slow data acquisition and a strong dependency of the data on the tip condition. A probe chip with thousands of sharp integrated tips is the basis of our concept. We have developed a nanofabrication protocol for Si based probe chips and their functionalization with metal and diamond coatings, evaluated our probe chips for various RTS SPM applications (multi-tip imaging, SPM tomography, and correlative SPM), and showed the high potential of the RTS SPM concept. [ABSTRACT FROM AUTHOR]

We report on‐surface synthesis of heterochiral 1D heptahelicene oligomers after deposition of a racemic heptahelicene monomer on an Au(111) surface followed by Ullmann coupling under ultrahigh vacuum conditions. Structure, chirality and mode of adsorption of the resulting dimers to octamers are inferred from the scanning probe microscopy and theoretical calculations. [ABSTRACT FROM AUTHOR]

2D materials are intriguing due to their remarkably thin and flat structure. This unique configuration allows the majority of their constituent atoms to be accessible on the surface, facilitating easier electron tunneling while generating weak surface forces. To decipher the subtle signals inherent in these materials, the application of techniques that offer atomic resolution (horizontal) and sub‐Angstrom (z‐height vertical) sensitivity is crucial. Scanning probe microscopy (SPM) emerges as the quintessential tool in this regard, owing to its atomic‐level spatial precision, ability to detect unitary charges, responsiveness to pico‐newton‐scale forces, and capability to discern pico‐ampere currents. Furthermore, the versatility of SPM to operate under varying environmental conditions, such as different temperatures and in the presence of various gases or liquids, opens up the possibility of studying the stability and reactivity of 2D materials in situ. The characteristic flatness, surface accessibility, ultra‐thinness, and weak signal strengths of 2D materials align perfectly with the capabilities of SPM technologies, enabling researchers to uncover the nuanced behaviors and properties of these advanced materials at the nanoscale and even the atomic scale. [ABSTRACT FROM AUTHOR]

In this study, a Y2O3 insulator was fabricated via the sol–gel process and the effect of precursors and annealing processes on its electrical performance was studied. Yttrium(III) acetate hydrate, yttrium(III) nitrate tetrahydrate, yttrium isopropoxide oxide, and yttrium(III) tris (isopropoxide) were used as precursors, and UV/ozone treatment and high-temperature annealing were performed to obtain Y2O3 films from the precursors. The structure and surface morphologies of the films were characterized via grazing-incidence X-ray diffraction and scanning probe microscopy. Chemical component analysis was performed via X-ray spectroscopy. Electrical insulator characteristics were analyzed based on current density versus electrical field data and frequency-dependent dielectric constants. The Y2O3 films fabricated using the acetate precursor and subjected to the UV/ozone treatment showed a uniform and flat surface morphology with the lowest number of oxygen vacancy defects and unwanted byproducts. The corresponding fabricated capacitors showed the lowest current density (Jg) value of 10−8 A/cm2 at 1 MV/cm and a stable dielectric constant in a frequency range of 20 Hz–100 KHz. At 20 Hz, the dielectric constant was 12.28, which decreased to 10.5 at 105 Hz. The results indicate that high-quality, high-k insulators can be fabricated for flexible electronics using suitable precursors and the suggested low-temperature fabrication methods. [ABSTRACT FROM AUTHOR]

The article discusses the application of scanning thermal microscopy (SThM) for localizing and monitoring defects in electronics, emphasizing its role in thermal management, defect detection, and performance improvement of microelectronic technologies. It introduces the principle of SThM instruments, describes their operation in passive and active modes, and highlights their capabilities in detecting localized inhomogeneities and overheating in electronic components.

Detecting ferroelectricity at micro- and nanoscales is crucial for advanced nanomaterials and materials with complicated topography. Switching spectroscopy piezoresponse force microscopy (SSPFM), which involves measuring piezoelectric hysteresis loops via a scanning probe microscopy tip, is a widely accepted approach to characterize polarization reversal at the local scale and confirm ferroelectricity. However, the local hysteresis loops acquired through this method often exhibit unpredictable shapes, a phenomenon often attributed to the influence of parasitic factors such as electrostatic forces and current flow. Our research has uncovered that the deviation in hysteresis loop shapes can be caused by spontaneous backswitching occurring after polarization reversal. Moreover, we've determined that the extent of this effect can be exacerbated when employing inappropriate SSPFM waveform parameters, including duration, frequency, and AC voltage amplitude. Notably, the conventional 'pulse-mode' SSPFM method has been found to intensify spontaneous backswitching. In response to these challenges, we have redesigned SSPFM approach by introducing the positive up-negative down (PUND) method within the 'step-mode' SSPFM. This modification allows for effective probing of local piezoelectric hysteresis loops in ferroelectrics with reversible piezoresponse while removing undesirable electrostatic contribution. This advancement extends the applicability of the technique to a diverse range of ferroelectrics, including semiconductor ferroelectrics and relaxors, promising a more reliable and accurate characterization of their properties. [ABSTRACT FROM AUTHOR]

Microscopy has been pivotal in improving the understanding of structure‐function relationships at the nanoscale and is by now ubiquitous in most characterization labs. However, traditional microscopy operations are still limited largely by a human‐centric click‐and‐go paradigm utilizing vendor‐provided software, which limits the scope, utility, efficiency, effectiveness, and at times reproducibility of microscopy experiments. Here, a coupled software–hardware platform is developed that consists of a software package termed AEcroscopy (short for Automated Experiments in Microscopy), along with a field‐programmable‐gate‐array device with LabView‐built customized acquisition scripts, which overcome these limitations and provide the necessary abstractions toward full automation of microscopy platforms. The platform works across multiple vendor devices on scanning probe microscopes and electron microscopes. It enables customized scan trajectories, processing functions that can be triggered locally or remotely on processing servers, user‐defined excitation waveforms, standardization of data models, and completely seamless operation through simple Python commands to enable a plethora of microscopy experiments to be performed in a reproducible, automated manner. This platform can be readily coupled with existing machine‐learning libraries and simulations, to provide automated decision‐making and active theory‐experiment optimization to turn microscopes from characterization tools to instruments capable of autonomous model refinement and physics discovery. [ABSTRACT FROM AUTHOR]

Surface/interface engineering of methylammonium lead bromide (MAPbBr3) single crystals (SCs) is crucial for carrier generation/recombination, separation, and transportation, thereby enabling superior optoelectronics. Herein, a surface‐engineered crystallization technique is presented in which a thin polycrystalline MAPbBr3 layer is in situ grown on the surface of bulk mm‐sized MAPbBr3 SCs. The growth direction and the atomic distribution of both the polycrystalline surface layer and the single crystalline core have been analyzed by damage‐free atomic‐resolution transmission electron microscopy (TEM). The polycrystalline nature of the crystals gives rise to bright green emission under UV light. Scanning probe microscopy results show that the current at the emissive MAPbBr3 film/MAPbBr3 SC surface is five times higher than that at a non‐emissive surface when illuminated. Lateral photodetectors based on MAPbBr3 film/MAPbBr3 SCs can achieve excellent detectivities (≈1013 Jones) and high photoresponsivities (≈20 A W−1). Furthermore, a semiconductor‐based fluorescence quick response (FQR) code is patterned on the same bright green‐emitting surface of the MAPbBr3 film/MAPbBr3 SC using a picosecond laser pulse, with a scalability of 3 × 3 mm2. An FQR code integrated with a photodetector may serve as a potential double security tag in bank cards, passports, door security, etc. [ABSTRACT FROM AUTHOR]

The development of new technologies for the current energy and environmental challenges requires the acquisition of a very fundamental knowledge about the structure and activity of catalytic materials at the nanometric scale. As a consequence, in situ and operando methodologies are blossoming, but only a fraction of them really aims at a local vision that would allow watching atoms at work during reactions. In this short report, we want to outline the merits of a new technique based on scanning tunnelling microscopy (Current-roughness electrochemical scanning tunneling microscopy, cr-EC-STM) which can visualize electrocatalytic reactions down at the single atom level. Results of two case studies in the field of hydrogen evolution reaction (HER) are briefly summarized, witnessing the capability of cr-EC-STM to provide critical information about the structure and catalytic performance of the active sites with atomic resolution. [ABSTRACT FROM AUTHOR]

Strained macrocycles display interesting properties, such as conformational rigidity, often resulting in enhanced π‐conjugation or enhanced affinity for non‐covalent guest binding, yet they can be difficult to synthesize. Here we use computational modeling to design a template to direct the formation of an 18‐porphyrin nanoring with direct meso‐meso bonds between the porphyrin units. Coupling of a linear 18‐porphyrin oligomer in the presence of this template gives the target nanoring, together with an unexpected 36‐porphyrin ring by‐product. Scanning tunneling microscopy (STM) revealed the elliptical conformations and flexibility of these nanorings on a Au(111) surface. [ABSTRACT FROM AUTHOR]

Photoresponsive supramolecular polymers have a major potential for applications in responsive materials that are externally triggered by light with spatio‐temporal control of their polymerisation state. While changes in macroscopic properties revealed the adaptive nature of these materials, it remains challenging to capture the dynamic depolymerisation process at the molecular level, which requires fast observation techniques combined with in situ irradiation. By implementing in situ UV illumination into a High‐Speed Atomic Force Microscope (HS‐AFM) setup, we have been able to capture the disassembly of a light‐driven molecular motor‐based supramolecular polymer. The real‐time visualisation of the light‐triggered disassembly process not only reveals cooperative depolymerisation, it also shows that this process continues after illumination is halted. Combining the data with cryo‐electron microscopy and spectroscopy approaches, we obtain a molecular‐level description of the motor‐based polymer dynamics reminiscent of actin chain‐end depolymerisation. Our detailed understanding of supramolecular depolymerisation will drive the development of future responsive polymer systems. [ABSTRACT FROM AUTHOR]

Polyimide films with molecular imprints of erythrosine and indigocarmine have been obtained. The structure and morphology of the film surfaces have been studied by scanning probe microscopy and IR spectroscopy. It has been found that the surface roughness of molecularly imprinted polymers (MIPs) increases, while the relief height amounts to 3–4 nm. The removal of template molecules leads to a redistribution of pores over sizes in the polymers with molecular imprints. The adsorption of dyes by MIP films has been carried out under static conditions. The degrees of extraction and the imprinting factors have been calculated for polymers with molecular imprints of the dyes. The high values of these parameters indicate the selectivity of MIPs to the target template molecules. [ABSTRACT FROM AUTHOR]

Low-temperature scanning probe microscopes (SPMs) are critical for the study of quantum materials and quantum information science. Due to the rising costs of helium, cryogen-free cryostats have become increasingly desirable. However, they typically suffer from comparatively worse vibrations than cryogen-based systems, necessitating the understanding and mitigation of vibrations for SPM applications. Here we demonstrate the construction of two cryogen-free dilution refrigerator SPMs with minimal modifications to the factory default and we systematically characterize their vibrational performance. We measure the absolute vibrations at the microscope stage with geophones and use both microwave impedance microscopy and a scanning single-electron transistor to independently measure tip-sample vibrations. Additionally, we implement customized filtering and thermal anchoring schemes and characterize the cooling power at the scanning stage and the tip electron temperature. This work serves as a reference to researchers interested in cryogen-free SPMs, as such characterization is not standardized in the literature or available from manufacturers. [ABSTRACT FROM AUTHOR]

Strained macrocycles display interesting properties, such as conformational rigidity, often resulting in enhanced π‐conjugation or enhanced affinity for non‐covalent guest binding, yet they can be difficult to synthesize. Here we use computational modeling to design a template to direct the formation of an 18‐porphyrin nanoring with direct meso‐meso bonds between the porphyrin units. Coupling of a linear 18‐porphyrin oligomer in the presence of this template gives the target nanoring, together with an unexpected 36‐porphyrin ring by‐product. Scanning tunneling microscopy (STM) revealed the elliptical conformations and flexibility of these nanorings on a Au(111) surface. [ABSTRACT FROM AUTHOR]

Photoresponsive supramolecular polymers have a major potential for applications in responsive materials that are externally triggered by light with spatio‐temporal control of their polymerisation state. While changes in macroscopic properties revealed the adaptive nature of these materials, it remains challenging to capture the dynamic depolymerisation process at the molecular level, which requires fast observation techniques combined with in situ irradiation. By implementing in situ UV illumination into a High‐Speed Atomic Force Microscope (HS‐AFM) setup, we have been able to capture the disassembly of a light‐driven molecular motor‐based supramolecular polymer. The real‐time visualisation of the light‐triggered disassembly process not only reveals cooperative depolymerisation, it also shows that this process continues after illumination is halted. Combining the data with cryo‐electron microscopy and spectroscopy approaches, we obtain a molecular‐level description of the motor‐based polymer dynamics reminiscent of actin chain‐end depolymerisation. Our detailed understanding of supramolecular depolymerisation will drive the development of future responsive polymer systems. [ABSTRACT FROM AUTHOR]

Dynamic light scattering, atomic force and transmission electron microscopy were used to characterize three different types of potential carriers of double-stranded RNA (dsRNA): calcium phosphate particles, chitosan particles, and hybrid particles consisting of an inorganic core coated with chitosan. The hydrodynamic diameter and electrokinetic potential were measured, and the surface morphology of the three types of particles was studied. The interaction of dsRNA with the carriers was studied using electrophoresis and atomic force microscopy. The possibility of the dsRNA complexes formation with chitosan-based carriers, resulting from the interaction of dsRNA with the positively charged amino groups of chitosan, was demonstrated. [ABSTRACT FROM AUTHOR]

During the past decade, Scanning Probe Microscopy (SPM) based surface strain detection techniques have been extensively used in the characterization of functional materials, structures, and devices. Here, we refer these techniques as Surface Strain Force Microscopy (SSFM), which mainly includes the Piezoresponse Force Microscopy, Atomic Force Acoustic Microscopy, Atomic Force Microscopy-Infrared spectroscopy (or photothermal induced resonance), Piezomagnetic Force Microscopy, and Scanning Joule Expansion Microscopy. The inception of SSFM opens up a pathway to study the nanoscale physical properties by using a sharp tip to detect the local field-induced surface strain. Through measuring the signals of the surface strain, multiple physical properties, such as the electromechanical, mechanical, photothermal, magnetic, thermoelastic properties, can be characterized with an unprecedented spatial resolution. In order to further develop and overcome the fundamental issues and limitations of the SSFM, the multi-frequency SPM technology has been introduced to the SSFM-based techniques, leading to the emerging of multi-frequency SSFM (MF-SSFM). As a technical breakthrough of the SSFM, MF-SSFM has demonstrated substantial improvements in both performance and capability, resulting in increased attentions and numerous developments in recent years. This Perspective is, therefore, aimed at providing a preliminary summary and systematic understanding for the emerging MF-SSFM technology. We will first introduce the basic principles of conventional SSFM and multi-frequency SPM techniques, followed by a detailed discussion about the existing MF-SSFM techniques. MF-SSFM will play an increasingly important role in future nanoscale characterization of the physical properties. As a result, many more advanced and complex MF-SSFM systems are expected in the coming years. [ABSTRACT FROM AUTHOR]

Li[Ni0.885Co0.1V0.015]O2 (NCV), Li[Ni0.9Co0.1]O2 (NC), and Li[Ni0.885Co0.1Al0.015]O2 (NCA) nanoparticles are synthesized by means of oxalic acid co-precipitation with subsequent calcination. The evolution of Li-ion diffusion and deformation of both NCV and NCA under an external electric field are characterized by means of conductive atomic force microscopy and electrochemical strain microscopy. Macroscopic electrochemical characterization reveals that the Li-ion diffusivity in NCA is greater than that in NCV, and the undesirable irreversible H2–H3 phase transition occurs more readily in NCV than in NCA. The scanning probe microscopy results corroborate well with the macroscopic electrochemical measurements, which tell that vanadium and aluminum substitution can accelerate Li+ diffusion kinetics and enhance the reversibility of the H2–H3 phase transformation during the electrochemical process in varying degrees. [ABSTRACT FROM AUTHOR]

Y 2 O 3 /AlN composite films with different thicknesses of AlN interlayer were prepared on CVD diamond by RF magnetron sputtering. The influence of AlN thickness on the microstructure, adhesion strength, film stress, thermal shock resistance and infrared transmittance of the films was investigated by X-ray diffractometer, scanning electron microscopy, scanning probe microscopy, UV–Vis spectrophotometer, Fourier transform infrared spectrometer, scratch tester and 3-D optical surface profiler. The results show that CVD diamond coated with Y 2 O 3 /AlN composite films with different thicknesses of AlN have different degrees of anti-reflective effects in the 8–10 μm infrared band. The adhesion strength and quality of the composite film were improved with the AlN thickness increased, and the anti-reflective and anti-thermal shock of the film showed a trend of first increasing and then decreasing. CVD diamond coated with Y 2 O 3 /AlN composite films with 700 nm AlN interlayer has an average transmittance of 77 % in the 8–10 μm band and a good adhesion between interfaces. It can withstand rapid temperature changes and effectively protect the diamond substrate with little or no degradation of infrared optical properties. [ABSTRACT FROM AUTHOR]

Mixed‐dimensional heterostructures provide additional freedom to construct diverse functional electronic and optoelectronic devices, gaining significant interest. Herein, highly‐aligned pseudo‐1D tellurium is epitaxially grown on 2D monolayer transition metal dichalcogenides (TMDs), including MoSe2, MoS2, and WS2. A one‐pot chemical vapor deposition (CVD) technique eliminates the normally required transfer steps, thereby producing mixed‐dimensional heterostructures with an ultraclean interface. The controllable epitaxial growth of Te/TMD heterostructures are verified by Raman, scanning probe microscopy (SPM), and transmission electron microscopy (TEM) observation. The photoluminescence results indicate that the emission from TMDs is quenched in the heterostructure, confirming the efficient transfer of photogenerated carriers from TMDs to Te. Additionally, the mixed‐dimensional p‐n Te/MoSe2 heterojunction photodetector presents self‐driven behavior with high responsivity (328 mA W−1), external quantum efficiency (79%), and specific detectivity (8.2 × 109 Jones). The modified facile synthesis strategy and proposed growth mechanism in this study shed light on synthesizing mixed‐dimensional heterojunctions. This opens avenues for fabricating functional devices with reduced sizes and high densities, further enabling miniaturization and integration opportunities. [ABSTRACT FROM AUTHOR]

Carbyne, an elusive sp -hybridized linear carbon allotrope, has fascinated chemists and physicists for decades. Due to its high chemical reactivity and extreme instability, carbyne was much less explored in contrast to the sp2 -hybridized carbon allotropes such as graphene. Herein, we report the on-surface synthesis of polyynic carbon chains by demetallization of organometallic polyynes on the Au(111) surface; the longest one observed consists of ∼60 alkyne units (120 carbon atoms). The polyynic structure of carbon chains with alternating triple and single bonds was unambiguously revealed by bond-resolved atomic force microscopy. Moreover, an atomically precise polyyne, C14, was successfully produced via tip-induced dehalogenation and ring-opening of the decachloroanthracene molecule (C14Cl10) on a bilayer NaCl/Au(111) surface at 4.7 K, and a band gap of 5.8 eV was measured by scanning tunnelling spectroscopy, in a good agreement with the theoretical HOMO–LUMO gap (5.48 eV). [ABSTRACT FROM AUTHOR]

Electrocatalysis plays a pivotal role in renewable energy conversion and associated chemical production, enabling a variety of emerging sustainability technologies with societal impacts. Achieving marked improvement in electrocatalytic performance relies on a deep understanding of catalyst microstructures and catalytic mechanisms, with a particular emphasis on the detailed, spatiotemporally resolved characterizations of the underlying fundamental electrocatalytic processes. This fundamental need drives the development of operando imaging techniques, which improve the ability to detect dynamic structural changes in electrocatalysts and establish clear structure‐performance relationships for morphologically complex, hierarchically structured catalytic materials. This review aims to highlight significant advancements in the application of operando imaging techniques to develop a deeper understanding of important heterogeneous electrocatalytic reactions critical for emerging sustainability technologies. We summarize the up‐to‐date key mechanistic insights regarding these reactions achieved through a range of operando imaging techniques, including electron microscopies, X‐ray imaging techniques, scanning probe microscopies, and optical microscopies. We conclude by pointing out emerging directions and future prospects within the field of operando imaging in electrocatalysis. [ABSTRACT FROM AUTHOR]

A spectroscopic imaging-scanning tunneling microscope (SI-STM) allows for the atomic scale visualization of the surface electronic and magnetic structure of novel quantum materials with a high energy resolution. To achieve the optimal performance, a low vibration facility is required. Here, we describe the design and performance of an ultrahigh vacuum STM system supported by a hybrid vibration isolation system that consists of a pneumatic passive and a piezoelectric active vibration isolation stage. We present the detailed vibrational noise analysis of the hybrid vibration isolation system, which shows that the vibration level can be suppressed below 10−8 m/sec/√Hz for most frequencies up to 100 Hz. Combined with a rigid STM design, vibrational noise can be successfully removed from the tunneling current. We demonstrate the performance of our STM system by taking high resolution spectroscopic maps and topographic images on several quantum materials. Our results establish a new strategy to achieve an effective vibration isolation system for high-resolution STM and other scanning probe microscopies to investigate the nanoscale quantum phenomena. [ABSTRACT FROM AUTHOR]

The character of the electronic structure of acenes has been the subject of longstanding discussion. However, convincing experimental evidence of their open‐shell character has so far been missing. Here, we present the on‐surface synthesis of tridecacene molecules by thermal annealing of octahydrotridecacene on a Au(111) surface. We characterized the electronic structure of the tridecacene by scanning probe microscopy, which reveals the presence of an inelastic signal at 126 meV. We attribute the inelastic signal to spin excitation from the singlet diradical ground state to the triplet excited state. To rationalize the experimental findings, we carried out many‐body ab initio calculations as well as model Hamiltonians to take into account the effect of the metallic substrate. Moreover, we provide a detailed analysis of how the dynamic electron correlation and virtual charge fluctuation between the molecule and metallic surface reduces the singlet‐triplet band gap. Thus, this work provides the first experimental confirmation of the magnetic character of tridecacene. [ABSTRACT FROM AUTHOR]

The character of the electronic structure of acenes has been the subject of longstanding discussion. However, convincing experimental evidence of their open‐shell character has so far been missing. Here, we present the on‐surface synthesis of tridecacene molecules by thermal annealing of octahydrotridecacene on a Au(111) surface. We characterized the electronic structure of the tridecacene by scanning probe microscopy, which reveals the presence of an inelastic signal at 126 meV. We attribute the inelastic signal to spin excitation from the singlet diradical ground state to the triplet excited state. To rationalize the experimental findings, we carried out many‐body ab initio calculations as well as model Hamiltonians to take into account the effect of the metallic substrate. Moreover, we provide a detailed analysis of how the dynamic electron correlation and virtual charge fluctuation between the molecule and metallic surface reduces the singlet‐triplet band gap. Thus, this work provides the first experimental confirmation of the magnetic character of tridecacene. [ABSTRACT FROM AUTHOR]

Wurtzite ferroelectrics are an emerging material class that expands the functionality and application space of wide bandgap semiconductors. Promising physical properties of binary wurtzite semiconductors include a large, reorientable spontaneous polarization, direct band gaps that span from the infrared to ultraviolet, large thermal conductivities and acoustic wave velocities, high mobility electron and hole channels, and low optical losses. The ability to reverse the polarization in ternary wurtzite semiconductors at room temperature enables memory and analog type functionality and quasi-phase matching in optical devices and boosts the ecosystem of wurtzite semiconductors, provided the appropriate combination of properties can be achieved for any given application. In this article, advances in the design, synthesis, and characterization of wurtzite ferroelectric materials and devices are discussed. Highlights include: the direct and quantitative observation of polarization reversal of ∼135 μC/cm2 charge in Al1−xBxN via electron microscopy, Al1−xBxN ferroelectric domain patterns poled down to 400 nm in width via scanning probe microscopy, and full polarization retention after over 1000 h of 200 °C baking and a 2× enhancement relative to ZnO in the nonlinear optical response of Zn1−xMgxO. The main tradeoffs, challenges, and opportunities in thin film deposition, heterostructure design and characterization, and device fabrication are overviewed. [ABSTRACT FROM AUTHOR]

We describe an approach to determine the in-plane crystallographic surface directions in scanning probe microscopy (SPM) images. This method is based on a one-time characterization of the SPM instrument with an appropriate test sample and is exemplified by the analysis of non-contact atomic force microscopy (NC-AFM) images on surfaces whose natural cleavage occurs along {111} planes. We introduce a two-dimensional rotation matrix relating the crystallographic surface directions known from an analysis of the macroscopic crystal to the directions in the NC-AFM images. The procedure takes into account rotations and mirror axes resulting from sample mounting, the SPM scanner rotation, the choice of scan direction, as well as data processing, storage, and display. We demonstrate the practicability of the approach by determining the [ 11 2 ̄ ] direction in topographic images of a CeO2(111) film grown on a Si(111) wafer and atomic resolution images of CaF2(111) with an instrument based on the beetle-type scanner. [ABSTRACT FROM AUTHOR]

The effect of lattice relaxation instability (martensitic transition) on piezoelectric fields (EPE) in spontaneously ordered GaInP2/GaAs epitaxial layers was demonstrated using scanning Kelvin probe microscopy in combination with electron microscopy and optical spectroscopy measurements. The transition manifests itself in the dependence of the surface potential of the epi-layer on the mechanical (cleavage) and thermal (annealing) impacts. This is associated with a switching of the crystal lattice between relaxed and strained martensitic states, corresponding to a change in EPE in the epi-layer. The measured surface potential values (0.2–2.4 V) correspond to EPE within ±100 kV/cm and a strong decrease in |EPE| with increasing layer thickness, indicating the pinning of the Fermi level and piezoelectric doping. Our results open up the prospects for using spontaneously ordered semiconductor alloys to control electronic states in semiconductor nanostructures by controlling their piezoelectric fields. [ABSTRACT FROM AUTHOR]

Limited charge separation/transport efficiency remains the primary obstacle of achieving satisfying photoelectrochemical (PEC) water splitting performance. Therefore, it is essential to develop diverse interfacial engineering strategies to mitigate charge recombination. Despite obvious progress having been made, most works only considered a single‐side modulation in either the electrons of conduction band or the holes of valence band in a semiconductor photoanode, leading to a limited PEC performance enhancement. Beyond this conventional thinking, we developed a novel coupling modification strategy to achieve a composite electrode with bidirectional carrier transport for a better charge separation, in which Ti2C3Tx MXene quantum dots (MQDs) and α‐Fe2O3 nanodots (FO) are anchored on the surface of ZnIn2S4 (ZIS) nanoplates, resulting in markedly improved PEC water splitting of pure ZIS photoanode. Systematic studies indicated that the bidirectional charge transfer pathways were stimulated due to MQDs as "electron extractor" and S−O bonds as carriers transport channels, which synergistically favors significantly enhanced charge separation. The enhanced kinetic behavior at the FO/MQDs/ZIS interfaces was systematically and quantitatively evaluated by a series of methods, especially scanning photoelectrochemical microscopy. This work may deepen our understanding of interfacial charge separation, and provide valuable guidance for the rational design and fabrication of high‐performance composite electrodes. [ABSTRACT FROM AUTHOR]

This project aims to create a 316L stainless steel coated with a biocomposite based on chitosan for use in the biomedical industry. To completely coat the material, the dip-coating technique was used to apply plain chitosan, chitosan nanosilver, chitosan biotin, and chitosan-nanosilver-biotin in that order. This coating's surface morphology was investigated with field emission scanning electron microscopy (FESEM). Surface roughness, average size distribution, and 2D and 3D surface tomography were all investigated using scanning probe microscopy and atomic force microscopy (SPM and AFM). The Fourier transform infrared (FTIR) spectroscopy technique was used to quantify changes in functional groups. To evaluate the coated samples' wettability, contact angle measurements were also performed. The chitosan (CS) + nanosilver, CS + biotin, and CS + biotin + nanosilver-coated 316L stainless steel showed roughness values of about 8.68, 4.21, and 3.3 nm, respectively, compared with the neat chitosan coating, which exhibits 12 nm roughness, indicating a strong effect of biotin and nanosilver on surface topography whereas the coating layers were homogenous, measuring around 33 nm in thickness. For CS + nanosilver and CS + biotin, the average size of agglomerates was approximately 444 nm and 355 nm, respectively. The coatings showed adequate wettability for biomedical applications, were homogeneous, and had no cracks. Their contact angles were around 51–75 degrees. All of these results point to the composite coating's intriguing potential for use in biological applications. [ABSTRACT FROM AUTHOR]

Limited charge separation/transport efficiency remains the primary obstacle of achieving satisfying photoelectrochemical (PEC) water splitting performance. Therefore, it is essential to develop diverse interfacial engineering strategies to mitigate charge recombination. Despite obvious progress having been made, most works only considered a single‐side modulation in either the electrons of conduction band or the holes of valence band in a semiconductor photoanode, leading to a limited PEC performance enhancement. Beyond this conventional thinking, we developed a novel coupling modification strategy to achieve a composite electrode with bidirectional carrier transport for a better charge separation, in which Ti2C3Tx MXene quantum dots (MQDs) and α‐Fe2O3 nanodots (FO) are anchored on the surface of ZnIn2S4 (ZIS) nanoplates, resulting in markedly improved PEC water splitting of pure ZIS photoanode. Systematic studies indicated that the bidirectional charge transfer pathways were stimulated due to MQDs as "electron extractor" and S−O bonds as carriers transport channels, which synergistically favors significantly enhanced charge separation. The enhanced kinetic behavior at the FO/MQDs/ZIS interfaces was systematically and quantitatively evaluated by a series of methods, especially scanning photoelectrochemical microscopy. This work may deepen our understanding of interfacial charge separation, and provide valuable guidance for the rational design and fabrication of high‐performance composite electrodes. [ABSTRACT FROM AUTHOR]

l-Kynurenine (l-Kyn) is an endogenous metabolite produced in the catabolic route of l-Tryptophan (l-Trp), and it is a potential biomarker of several immunological disorders. Thus, the development of a fast and cheap technology for the specific detection of l-Kyn in biological fluids is of great relevance, especially considering its recent correlation with SARS-CoV-2 disease progression. Herein, a disposable screen-printed electrode based on a molecularly imprinted polymer (MIP) has been constructed: the o-Phenylenediamine monomer, in the presence of l-Kyn as a template with a molar ratio of monomer/template of 1/4, has been electropolymerized on the surface of a screen-printed carbon electrode (SPCE). The optimized kyn-MIP-SPCE has been characterized via cyclic voltammetry (CV), using [Fe(CN)6)]3−/4− as a redox probe and a scanning electron microscopy (SEM) technique. After the optimization of various experimental parameters, such as the number of CV electropolymerization cycles, urine pretreatment, electrochemical measurement method and incubation period, l-Kyn has been detected in standard solutions via square wave voltammetry (SWV) with a linear range between 10 and 100 μM (R2 = 0.9924). The MIP-SPCE device allowed l-Kyn detection in human urine in a linear range of 10–1000 μM (R2 = 0.9902) with LOD and LOQ values of 1.5 and 5 µM, respectively. Finally, a high selectivity factor α (5.1) was calculated for l-Kyn toward l-Trp. Moreover, the Imprinting Factor obtained for l-Kyn was about seventeen times higher than the IF calculated for l-Trp. The developed disposable sensing system demonstrated its potential application in the biomedical field. [ABSTRACT FROM AUTHOR]

Simplified two-electrode electrochemical deposition technique with glass/tin-doped indium oxide (glass/ITO) has been used to grow Mg-doped CdS thin films. As precursors, CdCl2, MgCl2 and Na2S2O3 were utilized. To study the physico-chemical properties of the obtained Mg-doped CdS thin-film instruments such as grazing incidence X-ray diffraction and Raman spectroscopy for structural analysis, UV–Vis spectrophotometry for optical properties and scanning probe microscopy for morphological properties have been used. It is observed from grazing incidence X-ray diffraction (GIXRD) data that the films are polycrystalline with only hexagonal phase. Because more metallic ions are deposited on the substrate, the material becomes more crystalline and increases the intensity of distinctive peaks observed. From the obtained optical characterization, it is observed that deposition time significantly influences the bandgap of the film. As deposition time raised from 10 to 25 min the bandgap decreases from 2.44 to 2.39 which makes the film to become more transparent and absorbs less light at shorter deposition times. According to scanning electron microscope (SEM) images, the surface morphology is uniform with tightly packed grains, and as deposition time goes on the grain shapes become less apparent. [ABSTRACT FROM AUTHOR]

Quartz tuning forks and qPlus-based force sensors offer an alternative approach to silicon cantilevers for investigating tip–sample interactions in scanning probe microscopy. The high-quality factor (Q) and stiffness of these sensors prevent the tip from jumping to the contact, even at sub-nanometer amplitude. The qPlus configuration enables simultaneous scanning tunneling microscopy and atomic force microscopy, achieving spatial resolution and spectroscopy at the subatomic level. However, to enable precise measurement of tip–sample interaction forces, confidence in these measurements is contingent upon the accurate calibration of the spring constant and oscillation amplitude of the sensor. Here, we have developed a method called astigmatic displacement microscopy with picometer sensitivity. [ABSTRACT FROM AUTHOR]

Growth cones of oligodendrocyte progenitor cells (OPCs) are challenging to investigate with conventional light microscopy due to their small size. Especially substructures such as filopodia, lamellipodia and their underlying cytoskeleton are difficult to resolve with diffraction limited microscopy. Light microscopy techniques, which surpass the diffraction limit such as stimulated emission depletion microscopy, often require expensive setups and specially trained personnel rendering them inaccessible to smaller research groups. Lately, the invention of expansion microscopy (ExM) has enabled super-resolution imaging with any light microscope without the need for additional equipment. Apart from the necessary resolution, investigating OPC growth cones comes with another challenge: Imaging the topography of membranes, especially label- and contact-free, is only possible with very few microscopy techniques one of them being scanning ion conductance microscopy (SICM). We here present a new imaging workflow combining SICM and ExM, which enables the visualization of OPC growth cone nanostructures. We correlated SICM recordings and ExM images of OPC growth cones captured with a conventional widefield microscope. This enabled the visualization of the growth cones' membrane topography as well as their underlying actin and tubulin cytoskeleton. [ABSTRACT FROM AUTHOR]

This work uses the sonochemical method to represent synthesized cobalt oxide nanoparticles (Co3O4) and analysed using different techniques. The X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR) examinations of the synthesized nanoparticles confirmed their cubic structure and average crystallite size of 21.3 nm. The spherical surface shape and presence of components with a particle size of 25.3 nm were revealed. Scanning probe microscopy (SPM) methods analysed the Co3O4 coated plates' surface characteristics, including roughness and topographical ideas. An aqueous electrolyte medium (6 M KOH) was used to investigate the electrochemical corrosion behaviour of Co3O4-coated plates. According to the Tafel plot, coating Zn plates with a high surface area and mesoporous Co3O4 in KOH electrolytes greatly reduced the corrosion of the plates. The coated plates are thermally treated up to 600°. The temperature-dependent anticorrosive properties of Co3O4 NPs are evaluated. [ABSTRACT FROM AUTHOR]

On‐surface synthesis serves as a powerful approach to construct π‐conjugated carbon nanostructures that are not accessible by conventional wet chemistry. Nevertheless, this method has been limited by the types and numbers of available on‐surface transformations. While the majority of successful cases exploit thermally triggered dehalogenative carbon–carbon coupling and cyclodehydrogenation, rearrangement of appropriate functional moieties has received limited research attention. Here, the unprecedented interchain coupling and thermally induced skeleton rearrangement are described of (dihydro)indeno[2,1‐b]fluorene (IF) polymers on an Au(111) surface under ultrahigh vacuum conditions, leading to different ladder polymers as well as fully fused graphene nanoribbon segments containing pentagonal and heptagonal rings. Au‐coordinated nanoribbons are also observed. All structures are unambiguously characterized by high‐resolution scanning probe microscopy. The current results provide an avenue to fabricating a wider variety of π‐conjugated polymers and carbon nanostructures comprising nonhexagonal rings as well as rarely explored organometallic nanoribbons. [ABSTRACT FROM AUTHOR]

The glycocalyx is a brush-like layer that covers the surfaces of the membranes of most cell types. It consists of a mixture of carbohydrates, mainly glycoproteins and proteoglycans. Due to its structure and sensitivity to environmental conditions, it represents a complicated object to investigate. Here, we review studies of the glycocalyx conducted using scanning probe microscopy approaches. This includes imaging techniques as well as the measurement of nanomechanical properties. The nanomechanics of the glycocalyx is particularly important since it is widely present on the surfaces of mechanosensitive cells such as endothelial cells. An overview of problems with the interpretation of indirect data via the use of analytical models is presented. Special insight is given into changes in glycocalyx properties during pathological processes. The biological background and alternative research methods are briefly covered. [ABSTRACT FROM AUTHOR]

We outline an approach to fabricate nanoscale artificial quasiperiodic tilings with thermal‐scanning probe lithography. Quasiperiodic tilings such as the Ammann‐Beenker, Square Fibonacci tiling, and Penrose are fabricated and imaged with thermal‐conductance feedback microscopy, followed by electron microscopy. The design implementation, chemical, and physical challenges involved in fabricating such artificial systems using nanolithography are discussed. Additionally, the potential applications of fabricated quasiperiodic tilings are explored. [ABSTRACT FROM AUTHOR]

The paper proposes a method for determining the instrumental function for measuring the surface potential in the Kelvin probe microscopy mode. The method is based on the use of SiC samples with regions of single-layer and double-layer graphene as a test structure. The measurement of potential profiles along different directions on such a surface makes it possible to determine the instrumental function for measurements of the potential. Using the instrumental function, one can perform a deconvolution procedure and restore the exact surface potential. [ABSTRACT FROM AUTHOR]

Definition: Scanning electrochemical microscopy (SECM) is a type of scanning probe microscopy (SPM) where an electrochemical reaction at a microelectrode is used to generate information about an electrochemically (in)active surface in its immediate vicinity. Careful preparation and knowledge of the microelectrode response as well as the application of a suitable method enable the study of spatially resolved electrochemical kinetics or the electrocatalytic activity of any structure or material. In addition to a wide range of other applications, the method has become particularly well established in the research field of electrochemical energy storage and conversion. [ABSTRACT FROM AUTHOR]

There is a rich of electric phenomena ubiquitously existing in novel quantum materials and advanced electronic devices. Microscopic understanding of the underlying physics relies on the sensitive and quantitative measurements of the electric field, electric current, electric potential, and other related physical quantities with a spatial resolution down to nanometers. Combined with a scanning probe microscope (SPM), the emergent quantum sensors of atomic/nanometer size provide promising platforms for imaging various electric parameters with a sensitivity beyond a single electron/charge. In this perspective, we introduce the working principle of such newly developed technologies, which are based on the strong sensitivity of quantum systems to external disturbances. Then we review the recent applications of those quantum sensors in nanoscale electric sensing and imaging, including a discussion of their privileges over conventional SPM techniques. Finally, we propose some promising directions for the future developments and optimizations of quantum sensors in nanoscale electric sensing and imaging. [ABSTRACT FROM AUTHOR]

The design of supramolecular networks based on organic molecules deposited on surfaces, is highly attractive for various applications. One of the remaining challenges is the expansion of monolayers to well-ordered multilayers in order to enhance the functionality and complexity of self-assemblies. In this study, we present an assessment of molecular conformation from 2D to 3D supramolecular networks adsorbed onto a HOPG surface under ambient conditions utilizing a combination of scanning probe microscopies and atomic force microscopy- infrared (AFM-IR). We have observed that the infrared (IR) spectra of the designed molecules vary from layer to layer due to the modifications in the dihedral angle between the C=O group and the neighboring phenyl ring, especially in the case of a 3D supramolecular network consisting of multiple layers of molecules. Supramolecular networks deposited on surfaces are of interest for a range of applications, but expanding monolayers to well-ordered multilayers remains a significant challenge, not least because analytical tools capable of probing such assemblies are limited. Here, the authors demonstrate that combining AFM-IR with STM enables an assessment of the differences in molecular conformations between 2D and 3D supramolecular networks adsorbed onto a HOPG surface. [ABSTRACT FROM AUTHOR]

Major advancements in fields as diverse as biology and quantum computing have relied on a multitude of microscopy techniques. Despite the considerable proliferation of these instruments, significant bottlenecks remain in terms of processing, analysis, storage, and retrieval of the acquired datasets. Aside from lack of file standards, individual domain‐specific analysis packages are often disjoint from the underlying datasets, and thus keeping track of analysis and processing steps remains tedious for the end‐user, hampering reproducibility. Here, the pycroscopy ecosystem of packages is introduced, an open‐source python‐based ecosystem underpinned by a common data model. The data model, termed the N‐dimensional spectral imaging data format, is realized in pycroscopy's sidpy package. This package is built on top of dask arrays, thus leveraging dask array attributes, but expanding them to accelerate microscopy relevant analysis and visualization. Several examples of the use of the pycroscopy ecosystem to create workflows for data ingestion and analysis of scanning transmission electron microscopy (STEM) and scanning probe microscopy data are shown. Adoption of such standardized routines will be critical to usher in the next generation of autonomous instruments where processing, computation, and meta‐data storage will be critical to overall experimental operations. [ABSTRACT FROM AUTHOR]

Using InSb/GaSb semiconductor quantum dots, we demonstrate the lateral spatial resolution of scattering apertureless near-field microscope equal to 10 – 15 nm at a wavelength of λ = 10.7 μm provided by a single-mode CO2 laser. The measurement conditions make it possible to undoubtedly exclude any artifacts caused by the sample topography and other similar factors. We identify the strongly localized in-plane near-field signal with a two-dimensional electron gas clamped on the InSb/GaSb interface of quantum dots. [ABSTRACT FROM AUTHOR]