NANOMETRIC VISUALIZATION OF LOCALIZED DAMAGE BY SCANNING PROBE MICROSCOPY

Imaging micro-cracks in gold films: a comparative study of scanning tunneling and atomic force microscopies

The direct modification of silicon and other semiconductor and metal surfaces by the process of anodization using the electric field from a scanning probe microscope in conjunction with the absorbed water from the atmosphere as the electrolyte is one promising method of accomplishing direct write lithography for the electron device fabrication using scanning probe microscopes. Both scanning tunneling microscopes and conductive-tip atomic force microscopes have been used for anodization with the work reported here primarily accomplished with a conductive-tip atomic force microscope. We have found that the terminating thickness of the scanning probe microscope induced oxide is governed by the diffusion limited electric field at the surface (which in this case is a function of the scanning probe microscope tip potential), with many similarities to liquid electrolyte anodization process. In particular, when using atmospheric water as the electrolyte on a silicon substrate and a conductive-tip atomic force microscope with a −7 to −10 V tip potential, the terminating electric field that is reached as the silicon dioxide thickness increases is to its final value of 80 Å is ∼1×107 V/cm. This is consistent with the diffusion limited electric field that is observed in many other anodization processes and the native oxidation of silicon (Mott–Cabrera process).

Scanning probe microscopy (SPM) can be successfully used in biological investigations1. Scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) are two main SPM techniques and they are capable of imaging biological objects at molecular level under in situ conditions. With this advantage, STM and AFM are applied to study not only the topographical structures of bio-samples in their natural environment, but also their electrochemical properties at liquid-solid interfaces. The electrochemical properties of biomolecules are usually studied by integral electrochemical methods, like cyclic voltammetry. The degree of surface coverage, the surface orientation of enzymes and the activity of a single enzyme remain a question of dispute, however, electrochemical SPM techniques can bring clarification. Electrochemical scanning tunnelling microscopy (EC-STM) and electrochemical atomic force microscopy (EC-AFM) provide visual topological information of biomolecules adsorbed on the electrode surface at single-molecular level. Some experimental issues, such as the requirement of the sample being conductive, potential damage to samples caused by the tunnelling current or tip-sample force, may limit their application. Scanning electrochemical potential microscopy (SECPM), a technique that measures the surface potential distribution at zero current, can be a promising alternative. SECPM shares most of the hardware setup with EC-STM except for the current amplifier being substituted by a potentiometer. It is easy to switch between SECPM and EC-STM to compare the topographical profile of the same area by mapping electron density and surface potential2. In our study, SPM techniques are used to study various biological objects, from nanometer-sized DNA and redox proteins to micrometer-sized bacteria spores. Since high-resolution images of DNA origami nanostructures can be achieved by using AFM3, we use both EC-AFM and SECPM techniques to investigate the morphology and potential-dependent adsorption behaviour of DNA scaffold and origamis4 on the modified HOPG surface. We found DNA scaffold can adsorb on HOPG in a certain potential range, and the adsorption structure changes with the applied electrochemical potential. Horseradish peroxidase (HRP), a redox enzyme, was studied using both, EC-STM and SECPM under in situ conditions5. HRP molecules were adsorbed on highly oriented pyrolytic graphite (HOPG) surfaces and imaged in phosphate buffered saline. We found that SECPM shows a better resolution than EC-STM in imaging this biomolecule. SECPM is also capable of measuring the surface charge distribution of the adsorbed biomolecules at the electrochemical interfaces. AFM in liquid was used to investigate the morphology and cellular process of Streptomycetes venezuelae both the wild type and the mutant6. To immobilize the bacteria on the surface for imaging, we use SiC patterned by photolithography with hole arrays (1.5×1.5×0.6 µm) to trap the bacteria and then measure under the physiological condition. The designed hole arrays trap the bacteria without causing any denaturation and due to the high electronic conductivity, they can serve as the working electrode under electrochemical conditions for EC-AFM and SECPM studies. EC-AFM was applied to image the morphology of the bacterial spore under different potential, and we found the morphology of the spore didn’t change in the wide potential window. (1) Choi, E.; Kim, A.; Son, H.; Pyo, S. G. J. Nanosci. Nanotechnol. 2014, 14 (1), 924. (2) Herpich, M.; Friedl, J.; Stimming, U. In Surface Science Tools for Nanomaterials Characterization; Springer Berlin Heidelberg: Berlin, Heidelberg, 2015; pp 1–67. (3) Bald, I.; Keller, A. Molecules 2014, 19 (9), 13803. (4) Kozyra, J.; Ceccarelli, A.; Torelli, E.; Lopiccolo, A.; Gu, J.-Y.; Fellermann, H.; Stimming, U.; Krasnogor, N. ACS Synth. Biol. 2017, 6 (7), 1140. (5) Baier, C.; Stimming, U. Angew. Chem. Int. Ed. Engl. 2009, 48 (30), 5542. (6) Santos-Beneit, F.; Gu, J.-Y.; Stimming, U.; Errington, J. Heliyon. Accepted

In this chapter, we discuss recent developments in the characterization of polarization doped wide bandgap semiconductor (WBS) heterojunctions with an emphasis on characterization by scanning probe microscopy (SPM). Wide bandgap semiconductors, such as SiC and GaN, have a wide variety of applications in electronic and optoelectronic devices [1–6]. The operation of devices made from these materials is dominated by the polarization properties of III-N and SiC semiconductor crystals. For example, polarization doped 2 dimensional electron gas (2DEG) channels in undoped GaN/AlGaN and SiC polytypic heterojunctions have been fabricated with current densites in excess of 1A/mm. Other effects, such as surface charge instability stemming from polarization, offer interesting potentials and challenges.While some of these effects may be studied using more conventional techniques such as currentvoltage (IV) and capacitance-voltage (CV) techniques (described in sections 2 and 3), others require probes capable of investigation on the nanometer scale. Transmission electron microscopy (TEM) can be used to investigate such polarizationinduced phenomena with atomic resolution, but involves destructive and laborious sample preparation. SPM techniques offer powerful, non-destructive tools to effectively and conveniently probe electronic materials and devices. Since the discovery of scanning tunneling microscopy (STM) in 1981 by Binnig and Rohrer [7], the field of SPM has advanced to encompass a large number of variations including, (i) STM, (ii) Atomic force microscopy (AFM), (iii) Electrostatic force microscopy (EFM), (iv) Scanning capacitance microscopy (SCM), (v) Scanning conduction microscopy (SCM), (vi) Magnetic force microscopy (MFM), (vii) Piezoelectric force microscopy (PFM), and (vii) Near field scanning optical microscopy (NSOM). Of the above modes, the first five modes have been extensively used for semiconductor characterization [8–15]. For WBS characterization, especially III-N, AFM, EFM and SCM modes are the most important due to the strong polarization of III-N and SiC. In the latter half of this chapter, we focus on the characterization of III-N by EFM operated in

INTRODUCTION Background History of Microscopy SCANNING PROBE MICROSCOPES (SPMS) Scanning Tunneling Microscope Electron Tunneling Atomic Force Microscope (AFM) Modes of Operation of AFM Simultaneous AFM and Scanning Near-Field Fluorescence (SNOM and SNOM-AFM) Friction Force Microscopy (FFM) STM and AFM Studies under Fluids Sample Preparation Procedures for STM and AFM Calibration and Image Analysis of STM and AFM Comparative Studies of Diverse Molecules by STM and AFM LIPID-LIKE MOLECULES ON SOLIDS AND SAMS Collapsed Lipid Monolayers (Self-Assembly) Domain Patterns in Monomolecular Film Assemblies Mixed Lipid Molecule Assemblies Holes in LB Films of Self-Assembly Monolayers Visualization of Vesicles by AFM LB Films of Liquid Crystals STM and AFM Studies of Diverse Molecules on Solids STM Studies on the Effect of Functional Group BIOPOLYMERS AND SYNTHETIC POLYMERS STRUCTURES BY STM AND AFM DNA Structures by STM and AFM SPM Studies of Three-Dimensional Protein Structures Protein Adsorption Studies by AFM Biological Macromolecular Structures Synthetic Polymers Studies by SPMs Mixed Monolayers of Macromolecules and Lipids Diverse Macromolecular Properties as Studied by SPMs Monolayers of Synthetic Polyamino Acids Biopolymer SAM Structures at Interfaces by STM and AFM CRYSTAL STRUCTURES BY STM AND AFM Crystal Structures of Small Molecules Surface Adsorption Studies by SPMs Macromolecule Crystals by STM and AFM STUDIES OF SOLID SURFACES BY SPMS Wetting Properties of Solid Surfaces AFM Analyses of Surface Acid-Base Properties Measurement of Attractive and Repulsive Forces by Atomic Force Microscope (AFM) DIVERSE APPLICATIONS OF SPMS (STM AND AFM, ETC.) AND NANOTECHNOLOGY STM and AFM in Organic Chemistry Semiconductor Study by SPM STM and AFM in Inorganic Chemistry Nanolithography and Nanomachining Qualitative and Quantitative Analyses at Nanoscale Application of SPMs under Dynamic Conditions Application of AFM to Immunodiagnostic Systems Applications of STM and AFM in Industry SPM Studies of Nanoscale Reactors Nanoscale Evaluation of Surface Roughness by SPMs Application of STM and AFM in Pollution Control Friction Force Microscope (FFM) Time-Resolved Analyses by STM REFERENCES

The surfaces of commensurate layered tellurides NbGe{sub 2/5}Te{sub 2}, NbGe{sub 1/3}Te{sub 2}, and NbSi{sub 1/2}Te{sub 2} were examined by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The observed atomic-resolution STM and AFM images were analyzed in terms of the partial and total electron density plots of their surfaces calculated by the extended Hueckel tight-binding electronic band structure method. The STM and AFM images of these phases are characterized by a pseudohexagonal arrangement of spots representing the surface Te atoms, and the surface unit-cell parameters of these commensurate MA{sub x}Te{sub 2} phases are well reproduced by STM and AFM. The atomic size patterns of the AFM and STM images differ in their relative contrasts from those expected on the basis of the surface Te-atom corrugations. This discrepancy is explained if the surface Te-atom sheets undergo a slight height reconstruction, most likely because the short interlayer Te{center_dot}{center_dot}{center_dot}Te contacts present in the bulk crystals are truncated at the surface. 12 refs., 13 figs.

This article provides data on the scanning tunnelling microscopy (STM), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) images of InAs(001) surface. Using the frequency-modulation (FM) method in AFM and KPFM, atomic resolution topography and contact potential difference (CPD) images of InAs(001) surface were obtained. The InAs(001) surface reconstruction images observed by STM and AFM are compared. The effect of AFM tip condition and tip-sample distance to AFM and KPFM imaging is verified by measuring frequency shift vs. tip-sample distance spectroscopy. This data article is related to the article entitled, “Kelvin prove force microscopy and its application” (Melitz et al., 2011) [1].

In his famous 1959 speech titled “There is plenty of room at the bottom” (1), Nobel prize winning physicist Richard P. Feynman predicts that matter will be controlled and manipulated at the atomic scale in the foreseeable future. Furthermore, he proclaims that “it should be possible to see... individual atoms.” In many ways, Feynman's vision was realized with the invention of the scanning tunneling microscope (STM) by Gerd Binnig and Heinrich Rohrer in 1982, for which they were awarded the Nobel prize in physics (2). With the STM, quantum mechanical tunneling of electrons from a sharp metal tip to a conductive substrate is used to detect individual surface atoms with atomic resolution. The ability to “see” atoms in real space immediately solved many controversies in surface science including the complicated 7 × 7 reconstruction of the Si(111) surface (3). One complication with the STM is that the tunneling current is a function of not only the surface topography but also the local electronic structure. On the graphite surface, there are two different types of carbon atoms in the basal plane, as distinguished by the presence (α) or absence (β) of a carbon atom in the plane immediately below the surface. Coupling of 2pz orbitals from α carbon atoms of adjacent layers lowers their bonding energies. Thus, the 2pz orbitals from β carbon atoms form the highest occupied (and lowest unoccupied) orbitals where the Fermi level crosses. These local electronic structure variations imply that the STM can only detect every other atom on the graphite surface. Consequently, an alternative imaging mechanism is required to detect the “hidden” α atoms on the graphite surface. The article by Hembacher et al. (4) in this issue of PNAS outlines a novel scanning probe microscope that solves the hidden atom problem. Their …

Scanning probe microscope (SPM)(including atomic force microscope (AFM), scanning tunneling microscope (STM) and Kelvin force probe microscope (KPFM)), etc.), tips have a great influence on physical and chemical properties of the sample surface. In this research, we explore the relationship between tip and structure of sample surface using AFM on Cu(110)-O surface. We observed two different types of c(6×2) phase on which Cu shows bright spot when the tip apex is O-terminated; on the other hand, O atoms shows bright spot when the tip apex is Cu-terminated. We also obtained that the tip has a great influence on the resolution, imaging, etc. Thus, we gave an explanation for both phenomena. This technique can be used for the fingerprinting and the identification of the chemical species on sample surfaces. And it is very important for the development of SPM technique.

<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto" id="d6099e80">The rising cost of liquid helium, traditionally used for cooling sophisticated low-temperature instruments, is increasingly impacting the operational costs of such systems. Recent advances in cryogenic technology have made closed-cycle cooling an attractive alternative, gradually replacing conventional "wet" cryostat designs. These closed-cycle systems now offer enhanced cooling power, temperature stability, and reduced vibration, making them suitable for integration with highly sensitive instruments, such as scanning probe microscopes (SPM). However, to achieve ultimate stability, sample purity, and the highest spatial and energy resolution, ultra-high vacuum (UHV) environments are essential. <p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" dir="auto" id="d6099e82">To meet the specific needs of the low-temperature SPM community, we have developed a UHV-based closed-cycle SPM dedicated for both scanning tunneling microscopy (STM) and atomic force microscopy (AFM) [ <a class="xref-link" href="#r1">1</a>]. Designed to be compact and acoustically quiet, this system can fit seamlessly into any laboratory environment. Unlike other commercially available systems, our solution provides long-term and stable operation at temperatures below 10 K, capable of running continuously for up to two years without interruption. The instrument’s compact SPM head allows easy optical access and can be integrated with optical components for advanced techniques, such as tip-enhanced Raman spectroscopy (TERS) or luminescence experiments. This innovative system offers a robust and sustainable platform for state-of-the-art research in nanotechnology and surface science.

Using scanning probe microscopy techniques, at low temperatures and in ultrahigh vacuum, individual molecules adsorbed on surfaces can be probed with ultrahigh resolution to determine their structure and details of their conformation, configuration, charge states, aromaticity, and the contributions of resonance structures. Functionalizing the tip of an atomic force microscope with a CO molecule enabled atomic-resolution imaging of single molecules, and measurement of their adsorption geometry and bond-order relations. In addition, by using scanning tunneling microscopy and Kelvin probe force microscopy, the density of the molecular frontier orbitals and the electric charge distribution within molecules can be mapped. Combining these techniques yields a high-resolution tool for the identification and characterization of individual molecules. The single-molecule sensitivity and the possibility of atom manipulation to induce chemical reactions with the tip of the microscope open up unique applications in chemistry, and differentiate scanning probe microscopy from conventional methods for molecular structure elucidation. Besides being an aid for challenging cases in natural product identification, atomic force microscopy has been shown to be a powerful tool for the investigation of on-surface reactions and the characterization of radicals and molecular mixtures. Herein we review the progress that high-resolution scanning probe microscopy with functionalized tips has made for molecular structure identification and characterization, and discuss the challenges it will face in the years to come.

In recent years, various electronic devices, including micromachine technology (MEMS), have been developed by nanotechnology. Since electrodeposition in an aqueous solution does not require a vacuum environment, various microfabrication and epitaxial control using electrodeposition have been investigated. Therefore, it is important to precisely and rapidly control the nanoscale interface structure during the electrodeposition process, and it is essential to elucidate the reaction process in the small region.Various methods have been studied for in-situ observation. The scanning probe microscope have given a way for atomic-scale observation, which can be applied to electrochemical nucleation and growth processes in an aqueous solution. However, the conventional scanning probe microscopes (scanning tunneling microscope: STM, atomic force microscope: AFM) require a few minutes to measure a surface, making it difficult to catch up the dynamic nucleation.A high-speed scanning probe microscope has the potential to overcome both the temporal and spatial problems. Magnussen et al. invented the video-rate STM and observed electrochemical interfacial phenomena such as metal nucleation, adatom diffusion, and molecular adsorption [1]. On the other hand, High-speed AFM (HS-AFM) was studied for biological samples [2]. Therefore, it is applicable to the imaging of soft surfaces and weakly adsorbed specimens.Taking advantage of the features of HS-AFM, we have observed Cu [3] and Zn deposition and dissolution (Fig. 1) as well as electrolytic nanobubble evolution [4]. In may talk, I would like to present dynamic behaviors of electrochemical nucleation and growth.

The surface topography of YBa2Cu3O7−δ thin films has been studied with both atomic force microscopy (AFM) and scanning tunneling microscopy (STM). The AFM images reveal a high density of small distinct nanoparticles, 10–50 nm across and 5–20 nm high, which do not appear in STM images of the same samples. In addition, we have shown that scanning the STM tip across the surface breaks off these particles and moves them to the edge of the scanned area, where they can later be imaged with the AFM.

We studied the O2 dissociated state under the different O2 exposed temperatures with atomic resolution by scanning probe microscopy (SPM) and imaged the O adatom by simultaneous atomic force microscopy (AFM)/scanning tunneling microscopy (STM). The effect of AFM operation mode on O adatom contrast was investigated, and the interaction of O adatom and the subsurface defect was observed by AFM/STM. Multi-channel exploration was performed to investigate the charge transfer between the adsorbed O and the TiO2(110) by obtaining the frequency shift, tunneling current and local contact potential difference at an atomic scale. The tunneling current image showed the difference of the tunneling possibility on the single O adatom and paired O adatoms, and the local contact potential difference distribution of the O-TiO2(110) surface institutively revealed the charge transfer from TiO2(110) surface to O adatom. The experimental results are expected to be helpful in investigating surface/interface properties by SPM.

Tip-enhanced Raman spectroscopy (TERS) has been developed by using atomic force microscopy and scanning tunneling microscopy since its birth in the early 2000s. Because, in principle, any scanning probe microscopy (SPM) can be combined with TERS, there is an increasing interest in extending TERS to other SPMs, especially the liquid-phase ones, targeting applications in biological or catalytic systems. We present the design, construction, and characterization of a laser-coupled scanning ion-conductance microscope (SICM) integrated with TERS for near-field spectroscopy under liquid environments. Key design elements include a full sample-scanning SICM, optics for TERS, and noise-isolating methods. The SICM-TERS system demonstrates direct-current and alternating-current SICM imaging modes on polydimethylsiloxane (PDMS) structures. Furthermore, the TERS capability was tested using silica-nanosphere-grafted PDMS. This work illustrates the feasibility and performance of SICM-TERS as a versatile tool for label-free nanoscale spectroscopy, opening new possibilities for real-time, in situ analysis of soft matter, electrochemical, and biological systems.