Scanning Probe Microscopy Applications Research Articles

In-situ resistance mapping of surface corrosion of iron using contact-mode carbon fibre as potentiometric tip

Scanning Probe Microscopy (SPM) has recently gained significant attention from both scientists and engineers for its unique capability to investigate localized corrosion phenomena. This paper introduces a novel application of SPM that offers a unique in-situ means to quantitatively evaluate the resistance of a spontaneously formed oxide layer on the conductive surface of an uncoated iron sample. This approach involved rastering a thin carbon fibre on the iron sample immersed on a corrosive medium while maintaining direct contact between the tip of the carbon fibre and the studied surface. Depending on the resistance between the tip and the sample, the measured voltage proportionally varied between 0 and the potential of the potentiometric circuit formed by the iron sample, the electrolyte and the carbon fibre. Through the application of the voltage divider formula, the measured potential map was transformed into a resistance map. This process allowed us to render a visual representation of the resistance distribution across the surface of the iron sample, providing some insights into the properties of the oxide layer.

Probe chip nanofabrication enabled reverse tip sample scanning probe microscopy concept and measurements

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.

Applications of scanning probe microscopy in neuroscience research

Abstract Scanning probe microscopy techniques allow for label-free high-resolution imaging of cells, tissues, and biomolecules in physiologically relevant conditions. These techniques include atomic force microscopy (AFM), atomic force spectroscopy, and Kelvin probe force microscopy, which enable high resolution imaging, nanomanipulation and measurement of the mechanoelastic properties of neuronal cells, as well as scanning ion conductance microscopy, which combines electrophysiology and imaging in living cells. The combination of scanning probe techniques with optical spectroscopy, such as with AFM-IR and tip-enhanced Raman spectroscopy, allows for the measurement of topographical maps along with chemical identity, enabled by spectroscopy. In this work, we review applications of these techniques to neuroscience research, where they have been used to study the morphology and mechanoelastic properties of neuronal cells and brain tissues, and to study changes in these as a result of chemical or physical stimuli. Cellular membrane models are widely used to investigate the interaction of the neuronal cell membrane with proteins associated with various neurological disorders, where scanning probe microscopy and associated techniques provide significant improvement in the understanding of these processes on a cellular and molecular level.

Recent advances in the application of scanning probe microscopy in interfacial electroanalytical chemistry

The electrochemical reaction mainly occurs at the electrode/electrolyte interface in the electrochemical system. For a fundamental insight into the interfacial reaction mechanism, in situ/operando analysis of the interfacial evolution at the microscale is essential. Scanning probe microscopy (SPM), noted for its high spatial resolution, real-time imaging, and multifunctional detection, is considered as one of the most important in situ analytical tools for the electrochemical interfaces from the atomic/molecular scale to the nanoscale. This review first introduces the brief principles of typical SPM, such as scanning tunneling microscopy, atomic force microscopy, and scanning electrochemical microscopy. The applications of in situ SPM in surface and interface analysis for electrochemical energy systems, including electrocatalysts and energy storage batteries, are then presented. In addition, in situ detection of the electric double layer and space charge layer is further discussed. Challenges and future developments in the field are proposed in the outlook.

Oil as an Enabler for Efficient Materials Removal in Three-Dimensional Scanning Probe Microscopy Applications

The ever-increasing complexity of semiconductor devices requires innovative three-dimensional materials characterization techniques for confined volumes. Multiple atomic force microscopy (AFM)-based methodologies, using a slice-and-measure approach have been proposed to meet this demand. They consist of scanning AFM probes that erode locally the sample’s material at a relatively high load while sensing with the secondary AFM channel, thus accessing in-depth information compared to the standard surface-limited analysis. Nonetheless, the rapid tip apex wear caused by the high forces involved, and the debris accumulation at the tip apex and inside/around the scan area, have been identified as major limitations to the accuracy and repeatability of the existing tomographic AFM sensing methods. Here we explore the use of oil as a suitable medium to overcome some of the issues such as the scan debris accumulation and the removal variability when working in air. We show how the use of oil preserves the tomographic operation while improving the efficiency in material removal for large depth sensing at a reduced debris accumulation. This is reported by comparing the results between air and oil environments, where the removal rate, depth accuracy, and tip-contamination are benchmarked. Finally, we provide the first demonstration of electrical AFM sensing using scanning spreading resistance microscopy (SSRM) in oil.

Applications of high-resolution scanning probe microscopy in hydroprocessing catalysis studies

Scanning probe microscopy offers real space atomic and nanoscale imaging of surfaces and supported nanoparticles, and these techniques are used in a planar catalyst model system context to analyze important atomic-scale aspects of nanoparticle structure, particle edges, defects, vacancies and to image the resulting interaction of individual reactants with the active surfaces. Here we review applications of high-resolution scanning probe microscopy to hydroprocessing catalysis, to demonstrate how these atom-resolved imaging techniques have recently advanced to become tools that elucidate the catalytically active edge structures of metal sulfide hydrotreating catalyst, resolve the intramolecular structure of complex hydrocarbons, and provide atomic-scale information on the mechanisms in which heteroatom-bearing hydrocarbons interact with a catalyst particle. This mini-review addresses the advantages of scanning tunneling microscopy for studies of planar model systems relevant for hydroprocessing catalysis, including the emerging use of near-ambient pressure (operando) scanning tunneling microscopy together with examples of the use of low-temperature molecular imaging with non-contact atomic force microscopy.

Characterization of Catalysts by Advanced Scanning Probe Microscopy and Spectroscopy

AbstractConsidering that there is a shortage of sustainable resources and that serious environmental issues need to be solved, the development of efficient catalysts has attracted a lot attention globally for energy saving and environmental improvement. In the last few decades, great progresses have been made in terms of fabrication and application of catalysts, however, systematic characterization with advanced technology and methods that enable researchers to have a detailed understanding of the catalysts’ properties and catalytic reactions, especially where an interface is present, are still limited. This Review focusses on the applications of advanced Scanning Probe Microscopy (SPM) and Spectroscopy techniques for the characterization of catalytic materials and their related reactions. A detailed description of advanced SPM and Spectroscopy techniques is introduced, followed by their applications in the characterization of surfaces and properties of common ordered catalytic materials including some coordination polymers and metal oxides. Various properties of these catalytic materials, such as conductivity, piezoelectricity, nanomechanics, photoresponse, and others, characterized by SPM and Spectroscopy are discussed. Subsequently, we introduce the high‐resolution imaging of chemical reactions and bond configuration by high‐resolution non‐contact Atomic Force Microscopy (NC‐AFM). Finally, the challenges involved in the development of SPM and Spectroscopy and an outlook for future research are presented. This Review provides fundamental insights into the characterization of heterogeneous catalysts and viewpoints to the development of smart catalytic materials.

Scanning Probe Microscopy Applications in Failure Analysis of Semiconductor Devices

Abstract Scanning probe microscopy (SPM) is widely used for fault isolation as well as diagnosing leakage current, detecting open circuits, and characterizing doping related defects. In this article, the author presents two SPM applications that are fairly uncommon but no less important in the scope of failure analysis. The first case involves the discovery of nano-steps on the surface of high-voltage NFETs, a phenomenon associated with stress-induced crystalline shift along the (111) silicon plane. In the second case, the author uses an AFM probe in the conductive mode to correlate tunneling current distribution with hot spots in high-k gate oxide films, which is shown to be a better indicator of oxide quality than rms surface roughness.

Focused Electron Beam-Based 3D Nanoprinting for Scanning Probe Microscopy: A Review.

Scanning probe microscopy (SPM) has become an essential surface characterization technique in research and development. By concept, SPM performance crucially depends on the quality of the nano-probe element, in particular, the apex radius. Now, with the development of advanced SPM modes beyond morphology mapping, new challenges have emerged regarding the design, morphology, function, and reliability of nano-probes. To tackle these challenges, versatile fabrication methods for precise nano-fabrication are needed. Aside from well-established technologies for SPM nano-probe fabrication, focused electron beam-induced deposition (FEBID) has become increasingly relevant in recent years, with the demonstration of controlled 3D nanoscale deposition and tailored deposit chemistry. Moreover, FEBID is compatible with practically any given surface morphology. In this review article, we introduce the technology, with a focus on the most relevant demands (shapes, feature size, materials and functionalities, substrate demands, and scalability), discuss the opportunities and challenges, and rationalize how those can be useful for advanced SPM applications. As will be shown, FEBID is an ideal tool for fabrication/modification and rapid prototyping of SPM-tipswith the potential to scale up industrially relevant manufacturing.

Diamond Colloidal Probe Force Spectroscopy.

Diamond is a highly attractive coating material as it is characterized by a wide optical transparency window, a high thermal conductivity, and an extraordinary robustness due to its mechanical properties and its chemical inertness. In particular, the latter has aroused a great deal of interest for scanning probe microscopy applications in recent years. In this study, we present a novel method for the fabrication of atomic force microscopy (AFM) probes for force spectroscopy using robust diamond-coated spheres, i.e., colloidal particles. The so-called colloidal probe technique is commonly used to study interactions of single colloidal particles, e.g., on biological samples like living cells, or to measure mechanical properties like the Young’s modulus. Under physiological measurement conditions, contamination of the particle often strongly limits the measurement time and often impedes reusability of the probe. Diamond as a chemically inert material allows treatment with harsh chemicals without degradation to refurbish the probe. Apart from that, the large surface area of spherical probes makes sensitive studies on surface interactions possible. This provides detailed insight into the interface of diamond with other materials and/or solvents. To fabricate such probes, silica microspheres were coated with a nanocrystalline diamond film and attached to tipless cantilevers. Measurements on soft polydimethylsiloxane (PDMS) show that the manufactured diamond spheres, even though possessing a rough surface, can be used to determine the Young’s modulus from a Derjaguin-Muller-Toporov (DMT) fit. By means of force spectroscopy, they can readily probe force interactions of diamond with different substrate materials under varying conditions. The influence of the surface termination of the diamond was investigated concerning the interaction with flat diamond substrates in air. Additionally, measurements in solution, using varying salt concentrations, were carried out, which provide information on double-layer and van-der-Waals forces at the interface. The developed technique offers detailed insight into surface chemistry and physics of diamond with other materials concerning long and short-range force interactions and may provide a valuable probe for investigations under harsh conditions but also on biological samples, e.g., living cells, due to the robustness, chemical inertness, and biocompatibility of diamond.

On-surface synthesis of carbon nanostructures by dehalogenative and dehydrogenative homocoupling reactions

Because of its diversity in nature, research on carbon materials has always been a hot topic. With the continuous development of nanotechnology, especially the application of scanning probe microscopy (SPM), surface chemistry has become one of the hot research areas. Recently, many researchers, including our group, have used scanning probe microscopy to fabricate a variety of novel carbon nanostructures through surface activation of hydrocarbons and carbon-halogen bonds under ultra-high vacuum (UHV) conditions. In this review, combined with the recent research work of this group, we focus on the study of the formation of carbon nanostructures on the metal surface through the activation of hydrocarbons and carbon halides, and explore the reactivity of the precursor molecules on the surface.

A fast imaging method of scanning ion conductance microscopy

Scanning ion conductance microscopy (SICM) has attracted considerable attention in the biological field as a noninvasive, high-resolution and non-force contact imaging technology. However, the development of improvement to the SICM imaging rate remains a great challenge for applications of rapid or dynamic imaging. In this paper, a fast SICM imaging method is proposed to improve the imaging efficiency via the design of a compressive sampling strategy and a reduction in the reconstruction time of sparse signals using the 2D normalized iterative hard thresholding (2D-NIHT) algorithm. The imaging performance of the method is validated by the simulation of recovery of a random synthetic image, and the superiority of the 2D-NIHT algorithm is also demonstrated by comparison of its reconstruction performance with that of other typical algorithms. The actual imaging performance of the method in SICM is also validated by the imaging of two biological samples, a virus and a living cell, and the results show that the method can duplicate the sample surface topography with high-definition and shorter imaging time. Our study offers a general imaging method for the applications of scanning probe microscopies to realize faster and higher-resolution imaging of biological samples.

One Second Formation of Large Area Graphene on a Conical Tip Surface via Direct Transformation of Surface Carbide.

Graphene functionalized nanotips are expected to possess promising potential for various applications based on the outstanding electrical and mechanical properties of graphene. However, current methods, usually requiring a high growth temperature and identical crystal surface to match graphene lattice, are suitable for graphene formation on a flat surface. It remains a big challenge to grow graphene on a nanosized convex surface and fabricate functionalized nanotips with high quality graphene at the apex. In this work, a novel ultrafast annealing method is developed for growing large area graphene on Ni nanotips within 1-2 s. Few layered or multiple layered graphene is presented on the apex or sidewall of the conical tip surface. Direct experimental evidences support that thus-produced graphene is formed via the direct conversion of nickel carbide at the outer surface under the instantaneous high temperature, which is different from the conventional segregation mechanism. This newly developed ultrafast method provides a new route to produce graphene efficiently and economically, promising for both convex surfaces and flat substrates. Moreover, the graphene functionalized nanotips exhibit a great potential for nanoelectrical measurements and conductive scanning probe microscopy (SPM) applications.

New Algorithm to Enable Construction and Display of 3D Structures from Scanning Probe Microscopy Images Acquired Layer-by-Layer.

Scanning probe microscopy (SPM), such as atomic force microscopy (AFM), is widely known for high-resolution imaging of surface structures and nanolithography in two dimensions (2D), providing important physical insights into surface science and material science. This work reports a new algorithm to enable construction and display of layer-by-layer 3D structures from SPM images. The algorithm enables alignment of SPM images acquired during layer-by-layer deposition and removal of redundant features and faithfully constructs the deposited 3D structures. The display uses a "see-through" strategy to enable the structure of each layer to be visible. The results demonstrate high spatial accuracy as well as algorithm versatility; users can set parameters for reconstruction and display as per image quality and research needs. To the best of our knowledge, this method represents the first report to enable SPM technology for 3D imaging construction and display. The detailed algorithm is provided to facilitate usage of the same approach in any SPM software. These new capabilities support wide applications of SPM that require 3D image reconstruction and display, such as 3D nanoprinting and 3D additive and subtractive manufacturing and imaging.

Design and characterization of a two-axis, flexure-based nanopositioning stage with 50 mm travel and reduced higher order modes

Long range, high precision, XY stages have a multitude of applications in scanning probe microscopy, lithography, micro-AM, wafer inspection and other fields. However, finding cost effective precision motion stages with a range of more than 12 mm with a precision better than one micron is a challenge. This study presents parametric design of the two XY flexure-based stages with a travel ranges of up to 50 mm and sub-micron resolution. First, the fabrication and testing of a two-axis double parallelogram flexure stage is presented and the results obtained from FEA and experimental measurements are shown to be in good agreement with the analytical predictions for this stage. A modified stage design with reduced higher order modes and same range, is also presented. This modified design is shown to be capable of achieving an open loop resolution of 100 nm with a travel range of greater than 50 mm. Higher order modes of the modified stage have been shown to be shifted from 25 Hz in the double parallelogram flexure (DPF) stage to over 86 Hz in the modified DPF stage making it much simpler to design a high speed (>10 Hz) controller for the modified stage.

Применение методов сканирующей зондовой микроскопии в исследовании опаловых наноструктур

Применение методов сканирующей зондовой микроскопии в исследовании опаловых наноструктур

Three-dimensional nanoscale imaging by plasmonic Brownian microscopy

AbstractThree-dimensional (3D) imaging at the nanoscale is a key to understanding of nanomaterials and complex systems. While scanning probe microscopy (SPM) has been the workhorse of nanoscale metrology, its slow scanning speed by a single probe tip can limit the application of SPM to wide-field imaging of 3D complex nanostructures. Both electron microscopy and optical tomography allow 3D imaging, but are limited to the use in vacuum environment due to electron scattering and to optical resolution in micron scales, respectively. Here we demonstrate plasmonic Brownian microscopy (PBM) as a way to improve the imaging speed of SPM. Unlike photonic force microscopy where a single trapped particle is used for a serial scanning, PBM utilizes a massive number of plasmonic nanoparticles (NPs) under Brownian diffusion in solution to scan in parallel around the unlabeled sample object. The motion of NPs under an evanescent field is three-dimensionally localized to reconstruct the super-resolution topology of 3D dielectric objects. Our method allows high throughput imaging of complex 3D structures over a large field of view, even with internal structures such as cavities that cannot be accessed by conventional mechanical tips in SPM.

Precise Nanoscale Measurements with Scanning Probe Microscopy (SPM): A Review.

For many of measurements, it is important to know the interaction of the measuring device with the artefact being measured in order to determine the accurate magnitude of the quantity. Mechanical, electrical, magnetic, optical and chemical properties of materials are also important parameters that need to be quantified at the micro and nanometre level. In this review, we introduce principles of scanning probe microscopy (SPM) and related technique; and also give the advance in nano-/micro-electro-mechanical systems (NEMS/MEMS) measurements using SPM. Firstly, we described state of the SPMs, their essential components and recent developments in this field. Then, conventional as well as advanced instruments have been addressed, measurement requirements discussed for measurement and fabrication. Finally, many different applications of SPMs in micro/nano electronics fields such as high resolution imaging, micro/nano-electronics, Metrology and manipulation and spectroscopy have been described in the article. Nevertheless, SPMs are advancing, supported by user-friendly and application-oriented features, improved software and combination with other instruments high precision measurement fields.

Preparation of multi‐tip arrays on flexible substrates for large‐scale microfabrication

Scanning probe microscopy (SPM) provides an important way for micro/nanofabrication. Compared with single-tip mode, parallel multi-tip mode enables an effective way for microfabrication with large scale and high efficiency by SPM. During the preparation of multi-tip array, the height difference between different tips is quite difficult to be eliminated. In the present work multi-tip arrays were prepared on different flexible rubber substrates with good bonding strength. Finite element analysis was carried out based on a hyperelastic constitutive model for selecting a suitable rubber substrate for producing the multi-tip array, and the initial shear modulus C 10 should be from 0.5 to 17. A series of comparative fabrication experiments were conducted by different multi-tip arrays. The multi-tip array with flexible substrates fulfilling the prediction model can compensate obviously the height difference resulting from microsphere size, and the flexible substrate with a lower C 10 in this range is better for the scratching fabrication. Using the multi-tip array, large-scale surface patterning can be fabricated with low cost and easy operation. This work can promote the wide application of SPM and development of the surface texture engineering.

Numerical performance analysis of quartz tuning fork-based force sensors

Quartz tuning fork-based force sensors where one prong is immobilized onto a holder while the other one is allowed to oscillate freely (‘qPlus’ configuration) are in widespread use for high-resolution scanning probe microscopy applications. Due to the small size of the tuning forks (≈3 mm) and the complexity of the sensor assemblies, the reliable and repeatable manufacturing of the sensors has been challenging. In this paper, we investigate the contribution of the amount and location of the epoxy glue used to attach the tuning fork to its holder on the sensor’s performance. Towards this end, we use finite element analysis to model the entire sensor assembly and to perform static and dynamic numerical simulations. Our analysis reveals that increasing the thickness of the epoxy layer between prong and holder results in a decrease of the sensor’s spring constant, eigenfrequency, and quality factor while showing an increasing deviation from oscillation in its primary modal shape. Adding epoxy at the sides of the tuning fork also leads to a degradation of the quality factor even though in this case, spring constant and eigenfrequency rise in tandem with a lessening of the deviation from its ideal modal shape.