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Kelvin Probe Force Microscope
Kelvin probe force microscopy (KPFM), also known as surface potential microscopy, is a noncontact variant of atomic force microscopy (AFM). By raster scanning in the x,y plane the work function of the sample can be locally mapped for correlation with sample features. When there is little or no magnification, this approach can be described as using a scanning Kelvin probe (SKP). These techniques are predominantly used to measure corrosion and coatings. With KPFM, the work function of surfaces can be observed at atomic or molecular scales. The work function relates to many surface phenomena, including catalytic activity, reconstruction of surfaces, doping and band-bending of semiconductors, charge trapping in dielectrics and corrosion. The map of the work function produced by KPFM gives information about the composition and electronic state of the local structures on the surface of a solid. History The SKP technique is based on parallel plate capacitor experiments performed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin Probe Force Microscopy
Kelvin probe force microscopy (KPFM), also known as surface potential microscopy, is a noncontact variant of atomic force microscopy (AFM). By raster scanning in the x,y plane the work function of the sample can be locally mapped for correlation with sample features. When there is little or no magnification, this approach can be described as using a scanning Kelvin probe (SKP). These techniques are predominantly used to measure corrosion and coatings. With KPFM, the work function of surfaces can be observed at atomic or molecular scales. The work function relates to many surface phenomena, including catalytic activity, reconstruction of surfaces, doping and band-bending of semiconductors, charge trapping in dielectrics and corrosion. The map of the work function produced by KPFM gives information about the composition and electronic state of the local structures on the surface of a solid. History The SKP technique is based on parallel plate capacitor experiments performed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SKP Fermi Level Diagram
SKP may refer to: Organisations * Communist Party of Finland (''Suomen Kommunistinen Puolue'') * Communist Party of Finland (1994) (''Suomen Kommunistinen Puolue'') * Communist Party of Georgia (''Sakartvelos Komunisturi Partia'') * Communist Party of Sweden (other) (''Sveriges Kommunistiska Parti''), several parties at different times Science and technology * Scanning Kelvin probe, a microscopy technique * SketchUp program file format Other uses * Skopje International Airport Skopje International Airport ( mk, Меѓународен аеродром Скопје, translit=Megjunaroden aerodrom Skopje, ), also known as Skopje Airport ( mk, Аеродром Скопје, translit=Aerodrom Skopje), and Petrovec Airport ... (IATA code: SKP), North Macedonia * SKP Degree College, Guntakal, Andhra Pradesh, India See also {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Force Microscope
Magnetic force microscopy (MFM) is a variety of atomic force microscopy, in which a sharp magnetized tip scans a magnetic sample; the tip-sample magnetic interactions are detected and used to reconstruct the magnetic structure of the sample surface. Many kinds of magnetic interactions are measured by MFM, including magnetic dipole–dipole interaction. MFM scanning often uses non-contact AFM (NC-AFM) mode. Overview In MFM measurements, the magnetic force between the sample and the tip can be expressed as :\vec F=\mu_o (\vec m \cdot \nabla ) \vec H \,\! where \vec m \, \! is the magnetic moment of the tip (approximated as a point dipole), \vec H \, \! is the magnetic stray field from the sample surface, and ''µ0'' is the magnetic permeability of free space. Because the stray magnetic field from the sample can affect the magnetic state of the tip, and vice versa, interpretation of the MFM measurement is not straightforward. For instance, the geometry of the tip magnetization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrostatic Force Microscope
Electrostatic force microscopy (EFM) is a type of dynamic non-contact atomic force microscopy where the electrostatic force is probed. ("Dynamic" here means that the cantilever is oscillating and does not make contact with the sample). This force arises due to the attraction or repulsion of separated charges. It is a long-range force and can be detected 100 nm or more from the sample. Force measurement For example, consider a conductive cantilever tip and sample which are separated a distance ''z'' usually by a vacuum. A bias voltage between tip and sample is applied by an external battery forming a capacitor, ''C'', between the two. The capacitance of the system depends on the geometry of the tip and sample. The total energy stored in that capacitor is ''U = ½ C⋅ΔV2''. The work done by the battery to maintain a constant voltage, ''ΔV'', between the capacitor plates (tip and sample) is ''-2U''. By definition, taking the negative gradient of the total energy ''Uto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies. Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy. Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, orbital resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and reso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Electrode
A reference electrode is an electrode which has a stable and well-known electrode potential. The high stability of the electrode potential is usually reached by employing a redox system with constant (buffered or saturated) concentrations of each participant of the redox reaction. There are many ways reference electrodes are used. The simplest is when the reference electrode is used as a half-cell to build an electrochemical cell. This allows the reduction potential, potential of the other half cell to be determined. An accurate and practical method to measure an electrode's potential in isolation (absolute electrode potential) has yet to be developed. Aqueous reference electrodes Common reference electrodes and potential with respect to the standard hydrogen electrode (SHE): * Standard hydrogen electrode (SHE) (E = 0.000 V) activity of H+ = 1 Molar * Normal hydrogen electrode (NHE) (E ≈ 0.000 V) concentration H+ = 1 Molar * Reversible hydrogen electrode (RHE) (E = 0.000 V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Kelvin Probe (SKP) Block Diagram
Kelvin probe force microscopy (KPFM), also known as surface potential microscopy, is a noncontact variant of atomic force microscopy (AFM). By raster scanning in the x,y plane the work function of the sample can be locally mapped for correlation with sample features. When there is little or no magnification, this approach can be described as using a scanning Kelvin probe (SKP). These techniques are predominantly used to measure corrosion and coatings. With KPFM, the work function of surfaces can be observed at atomic or molecular scales. The work function relates to many surface phenomena, including catalytic activity, reconstruction of surfaces, doping and band-bending of semiconductors, charge trapping in dielectrics and corrosion. The map of the work function produced by KPFM gives information about the composition and electronic state of the local structures on the surface of a solid. History The SKP technique is based on parallel plate capacitor experiments performed b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SKP Simplified
SKP may refer to: Organisations * Communist Party of Finland (''Suomen Kommunistinen Puolue'') * Communist Party of Finland (1994) (''Suomen Kommunistinen Puolue'') * Communist Party of Georgia (''Sakartvelos Komunisturi Partia'') * Communist Party of Sweden (other) (''Sveriges Kommunistiska Parti''), several parties at different times Science and technology * Scanning Kelvin probe, a microscopy technique * SketchUp program file format Other uses * Skopje International Airport Skopje International Airport ( mk, Меѓународен аеродром Скопје, translit=Megjunaroden aerodrom Skopje, ), also known as Skopje Airport ( mk, Аеродром Скопје, translit=Aerodrom Skopje), and Petrovec Airport ... (IATA code: SKP), North Macedonia * SKP Degree College, Guntakal, Andhra Pradesh, India See also {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock-in Amplifier
A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise components, potentially fairly close by in frequency, can still be reliably detected. It is essentially a homodyne detector followed by low-pass filter that is often adjustable in cut-off frequency and filter order. The device is often used to measure phase shift, even when the signals are large, have a high signal-to-noise ratio and do not need further improvement. Recovering signals at low signal-to-noise ratios requires a strong, clean reference signal with the same frequency as the received signal. This is not the case in many experiments, so the instrument can recover signals buried in the noise only in a limited set of circumstances. The lock-in amplifier is commonly believed to have been invented by Princeton University physicist Robert H. Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine Wave
A sine wave, sinusoidal wave, or just sinusoid is a curve, mathematical curve defined in terms of the ''sine'' trigonometric function, of which it is the graph of a function, graph. It is a type of continuous wave and also a Smoothness, smooth periodic function. It occurs often in mathematics, as well as in physics, engineering, signal processing and many other fields. Formulation Its most basic form as a function of time (''t'') is: y(t) = A\sin(2 \pi f t + \varphi) = A\sin(\omega t + \varphi) where: * ''A'', ''amplitude'', the peak deviation of the function from zero. * ''f'', ''frequency, ordinary frequency'', the ''Real number, number'' of oscillations (cycles) that occur each second of time. * ''ω'' = 2''f'', ''angular frequency'', the rate of change of the function argument in units of radians per second. * \varphi, ''phase (waves), phase'', specifies (in radians) where in its cycle the oscillation is at ''t'' = 0. When \varphi is non-zero, the entire waveform appears to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Charge
Surface charge is a two-dimensional surface with non-zero electric charge. These electric charges are constrained on this 2-D surface, and surface charge density, measured in coulombs per square meter (C•m−2), is used to describe the charge distribution on the surface. The electric potential is continuous across a surface charge and the electric field is discontinuous, but not infinite; this is unless the surface charge consists of a dipole layer. In comparison, the potential and electric field both diverge at any point charge or linear charge. In physics, at equilibrium, an ideal conductor has no charge on its interior; instead, the entirety of the charge of the conductor resides on the surface. However, this only applies to the ideal case of infinite electrical conductivity; The majority of the charge of an actual conductor resides within the skin depth of the conductor's surface. For dielectric materials, upon the application of an external electric field, the positive charg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
