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Scanning Probe Microscope
Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. SPM was founded in 1981, with the invention of the scanning tunneling microscope, an instrument for imaging surfaces at the atomic level. The first successful scanning tunneling microscope experiment was done by Gerd Binnig and Heinrich Rohrer. The key to their success was using a feedback loop to regulate gap distance between the sample and the probe. Many scanning probe microscopes can image several interactions simultaneously. The manner of using these interactions to obtain an image is generally called a mode. The resolution varies somewhat from technique to technique, but some probe techniques reach a rather impressive atomic resolution. This is largely because piezoelectric actuators can execute motions with a precision and accuracy at the atomic level or better on electronic command. This family of techniques can be called "piezoelectri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopy
Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical microscope, optical, electron microscope, electron, and scanning probe microscopy, along with the emerging field of X-ray microscopy. Optical microscopy and electron microscopy involve the diffraction, reflection (physics), reflection, or refraction of electromagnetic radiation/electron beams interacting with the Laboratory specimen, specimen, and the collection of the scattered radiation or another signal in order to create an image. This process may be carried out by wide-field irradiation of the sample (for example standard light microscopy and transmission electron microscope, transmission electron microscopy) or by scanning a fine beam over the sample (for example confocal laser scanning microscopy and scanning electron microscopy). Scan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Gate Microscopy
Scanning gate microscopy (SGM) is a scanning probe microscopy technique with an electrically conductive tip used as a movable gate that couples capacitively to the sample and probes electrical transport on the nanometer scale. Typical samples are mesoscopic devices, often based on semiconductor heterostructures, such as quantum point contacts or quantum dots. Carbon nanotubes too have been investigated. Operating principle In SGM one measures the sample's electrical conductance as a function of tip position and tip potential. This is in contrast to other microscopy techniques where the tip is used as a sensor, e.g., for forces. Development SGMs were developed in the late 1990s from atomic force microscopes. Most importantly, these had to be adapted for use at low temperatures, often 4 kelvin The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Ion-conductance Microscopy
Scanning ion-conductance microscopy (SICM) is a scanning probe microscopy technique that uses an electrode as the probe tip. SICM allows for the determination of the surface topography of micrometer and even nanometer-range structures in aqueous media conducting electrolytes. The samples can be hard or soft, are generally non-conducting, and the non-destructive nature of the measurement allows for the observation of living tissues and cells, and biological samples in general. It is able to detect steep profile changes in samples and can be used to map a living cell's stiffness in tandem with its detailed topography, or to determine the mobility of cells during their migrations.Happel, P.; Wehner, F.; Dietzel, I.D. Scanning ion conductance microscopy–a tool to investigate electrolyte-nonconductor interfaces. In Modern Research and Educational Topics in Microscopy; FORMATEX: Badajoz, Spain, 2007; pp. 968–975. Working principle Scanning ion conductance microscopy is a techniqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Electrochemical Microscopy
Scanning electrochemical microscopy (SECM) is a technique within the broader class of scanning probe microscopy (SPM) that is used to measure the local electrochemical behavior of liquid/solid, liquid/gas and liquid/liquid interfaces. Initial characterization of the technique was credited to University of Texas electrochemist, Allen J. Bard, in 1989. Since then, the theoretical underpinnings have matured to allow widespread use of the technique in chemistry, biology and materials science. Spatially resolved electrochemical signals can be acquired by measuring the current at an ultramicroelectrode (UME) tip as a function of precise tip position over a substrate region of interest. Interpretation of the SECM signal is based on the concept of diffusion-limited Electric current, current. Two-dimensional raster scan information can be compiled to generate images of surface reactivity and chemical kinetics. The technique is complementary to other surface characterization methods such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchrotron X-ray Scanning Tunneling Microscopy
A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The strength of the magnetic field which bends the particle beam into its closed path increases with time during the accelerating process, being ''synchronized'' to the increasing kinetic energy of the particles. The synchrotron is one of the first accelerator concepts to enable the construction of large-scale facilities, since bending, beam focusing and acceleration can be separated into different components. The most powerful modern particle accelerators use versions of the synchrotron design. The largest synchrotron-type accelerator, also the largest particle accelerator in the world, is the Large Hadron Collider (LHC) near Geneva, Switzerland, completed in 2008 by the European Organization for Nuclear Research (CERN). It can accelerate beams of protons to an energy of 7 teraelectronvolts (TeV o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Tunneling Potentiometry
Scan, SCAN or Scanning may refer to: Science and technology Computing and electronics * Graham scan, an algorithm for finding the convex hull of a set of points in the plane * 3D scanning, of a real-world object or environment to collect three dimensional data * Counter-scanning, in physical micro and nanotopography measuring instruments like scanning probe microscope * Elevator algorithm or SCAN, a disk scheduling algorithm * Image scanning, an optical scan of images, printed text, handwriting or an object * Optical character recognition, optical recognition of printed text or printed sheet music * Port scanner, in computer networking * Prefix sum, an operation on lists that is also known as the scan operator * Raster scan, the rectangular pattern of image capture and reconstruction in television * Scan chain, a type of manufacturing test used with integrated circuits * Scan line, one line in a raster scanning pattern * Screen reading, on computers to quickly locate text elem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photon Scanning Tunneling Microscopy
The operation of a photon scanning tunneling microscope (PSTM) is analogous to the operation of an electron scanning tunneling microscope, with the primary distinction being that PSTM involves tunneling of photons instead of electrons from the sample surface to the probe tip. A beam of light is focused on a prism at an angle greater than the critical angle of the refractive medium in order to induce total internal reflection within the prism. Although the beam of light is not propagated through the surface of the refractive prism under total internal reflection, an evanescent field of light is still present at the surface. The evanescent field is a standing wave which propagates along the surface of the medium and decays exponentially with increasing distance from the surface. The surface wave is modified by the topography of the sample, which is placed on the surface of the prism. By placing a sharpened, optically conducting probe tip very close to the surface (at a distance <λ) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin Polarized Scanning Tunneling Microscopy
Spin-polarized scanning tunneling microscopy (SP-STM) is a type of scanning tunneling microscope (STM) that can provide detailed information of magnetic phenomena on the single-atom scale additional to the atomic topography gained with STM. SP-STM opened a novel approach to static and dynamic magnetic processes as precise investigations of domain walls in ferromagnetic and antiferromagnetic systems, as well as thermal and current-induced switching of nanomagnetic particles. Principle of operation An extremely sharp tip coated with a thin layer of magnetic material is moved systematically over a sample. A voltage is applied between the tip and the sample allowing electrons to tunnel between the two, resulting in a current. In the absence of magnetic phenomena, the strength of this current is indicative for local electronic properties. If the tip is magnetized, electrons with spins matching the tip's magnetization will have a higher chance of tunneling. This is essentially the effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Hall Probe Microscopy
Scanning Hall probe microscope (SHPM) is a variety of a scanning probe microscope which incorporates accurate sample approach and positioning of the scanning tunnelling microscope with a semiconductor Hall sensor. Developed in 1996 by Oral, Simon J. Bending, Bending and Henini, SHPM allows mapping the Electromagnetic induction, magnetic induction associated with a sample. Current state of the art SHPM systems utilize 2D electron gas materials (e.g. gallium arsenide, GaAs/AlGaAs) to provide high spatial resolution (~300 nm) imaging with high magnetic field sensitivity. Unlike the magnetic force microscope the SHPM provides direct quantitative information on the magnetic state of a material. The SHPM can also image magnetic induction under applied fields up to ~1 Tesla (unit), tesla and over a wide range of temperatures (millikelvins to 300 K). The SHPM can be used to image many types of magnetic structures such as thin films, permanent magnets, MEMS structures, current carrying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Scanning Tunneling Microscope
The electrochemical scanning tunneling microscope (EC-STM) is a scanning tunneling microscope that measures the structures of surfaces and electrochemical reactions in solid-liquid interfaces at atomic or molecular scales. Development Electrochemical reactions occur in electrolytic solutions—for example electroplating, etching, batteries, and so on. On the electrode surface, many atoms, molecules, and ions adsorb and affect the reactions. In the past, in order to obtain information about the structure of electrode surfaces and reactions, the sample electrode was taken out of the electrolytic solution and measured under ultra high vacuum (UHV) conditions. In this case, the structure of the surface changed and could not be observed precisely. By using this microscope, however, these problems are resolved. Operation In electrolytic solutions, a complicated electrical double layer of H2O molecules and anions is formed. In this layer, as the distribution of anions changes w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballistic Electron Emission Microscopy
Ballistic electron emission microscopy or BEEM is a technique for studying ballistic electron transport through a variety of materials and material interfaces. BEEM is a three terminal scanning tunneling microscopy (STM) technique that was invented in 1988 at the Jet Propulsion Laboratory in Pasadena, California by L. Douglas Bell, Michael H. Hecht, and William J. Kaiser. The most popular interfaces to study are metal–semiconductor Schottky diodes, but metal–insulator–semiconductor systems can be studied as well. When performing BEEM, electrons are injected from a STM tip into a grounded metal base of a Schottky diode. A small fraction of these electrons will travel ballistically through the metal to the metal– semiconductor interface where they will encounter a Schottky barrier. Those electrons with sufficient energy to surmount the Schottky barrier will be detected as the BEEM current. The atomic scale positioning capability of the STM tip gives BEEM nanometer spat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Tunneling Microscopy
A scanning tunneling microscope (STM) is a type of scanning probe microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in Physics in 1986. STM senses the surface by using an extremely sharp conducting tip that can distinguish features smaller than 0.1 nm with a 0.01 nm (10 pm) depth resolution. This means that individual atoms can routinely be imaged and manipulated. Most scanning tunneling microscopes are built for use in ultra-high vacuum at temperatures approaching absolute zero, but variants exist for studies in air, water and other environments, and for temperatures over 1000 °C. STM is based on the concept of quantum tunneling. When the tip is brought very near to the surface to be examined, a bias voltage applied between the two allows electrons to tunnel through the vacuum separating them. The resulting ''tunneling current' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
