• Study Resource
  • Explore
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
PROBING AND MODELING VOLTAGE BREAKDOWN IN VACUUM
PROBING AND MODELING VOLTAGE BREAKDOWN IN VACUUM

... accelerate particles. Despite some differences, voltage breakdown in microwave resonators shares some features with breakdown in DC vacuum gaps (diodes). In both cases, the localized desorption of gas around an electron emission-source (e.g., field emission) could lead to breakdown. Analytical calcu ...
Tunneling from a correlated two-dimensional electron system transverse to a... * T. Sharpee and M. I. Dykman P. M. Platzman
Tunneling from a correlated two-dimensional electron system transverse to a... * T. Sharpee and M. I. Dykman P. M. Platzman

... A 2D electron system displays strong correlations if the ratio ⌫ of the characteristic Coulomb energy of the electronelectron interaction e 2 ( ␲ n) 1/2 to the characteristic kinetic energy is large 共here, n is the electron density兲. In degenerate systems the kinetic energy is the Fermi energy ␲ n/m ...
Tunnelling ionization of deep centres in high
Tunnelling ionization of deep centres in high

... frequencies permit the contactless and uniform application of strong electric fields. Despite the high radiation intensities involved, there is no or only insignificant heating of the electron gas or of the crystal lattice under these conditions [5]. This is the result of the extremely weak absorpti ...
Maxwell equation simulations of coherent optical photon emission from shock... * Evan J. Reed, Marin Soljačić,
Maxwell equation simulations of coherent optical photon emission from shock... * Evan J. Reed, Marin Soljačić,

... materials are typically characterized by a state of increasing uniaxial stress, i.e., the spatial gradient in the shock propagation direction component of the stress is nonzero. Such a spatial stress gradient can lead to the creation of a static material polarization or a shift in the existing stati ...
Digital DLTS studies on radiation induced defects in Si, GaAs and GaN
Digital DLTS studies on radiation induced defects in Si, GaAs and GaN

... otherwise take unreasonably long in an LIA system. Secondly, in principle only a single transient is required to do a complete analysis over the whole frequency range – this allows for much faster data acquisition and the recording of “single shot” events as are observed with metastable defects. Thi ...
A Study of Non-sequential Double Ionization of Atoms in Circularly
A Study of Non-sequential Double Ionization of Atoms in Circularly

... the electron is accelerated by the laser field and recollides with the parent ion and knocks out another electron. This process should be suppressed when the laser field is circularly polarized because recollision is impossible in this case. It is consistent with early experimental results. However, ...
Re-generable Field Emission Cathodes for
Re-generable Field Emission Cathodes for

... systems, a series of experiments were conducted to investigate the re-generable emitter tips. The experiments involved re-generating multiple emitter tips so that the electron performance of each re-generated tip could be evaluated and applied to the Fowler-Nordheim model to estimate the emitter tip ...
IOSR Journal of Applied Physics (IOSR-JAP)
IOSR Journal of Applied Physics (IOSR-JAP)

... characteristics of two n+ polysilicon gated n-channel MOSFETs are analyzed to characterize the metal-oxidesemiconductor device structure. The MOSFET data were reported by Eitan and Kolodny in 1983 and Rasras et al. in 2001. The first device has a thermal oxide of 8.5 nm and a substrate bias of -1V [ ...
Effects Of The Inversion Layer Centroid On MOSFET Behavior
Effects Of The Inversion Layer Centroid On MOSFET Behavior

... at 300 K. Nevertheless, the extension of the electron density inside the semiconductor and its effects on capacitance were noted early on by Pals, even at 300 K [2]. Two consequences of this fact that are important for device behavior are that 1) the electric potential value at the interface is grea ...
V. Discussion
V. Discussion

... neutrals for example, within the plasma can be identified. The disadvantage is that analysis of the spectra is complicated. This analysis was accomplished by developing a collisional-radiative (C-R) model, a technique which has been implemented with other helicon plasma experiments. 8,9 Both the arg ...
Introduction to the Physics of Field Ion Emitters
Introduction to the Physics of Field Ion Emitters

... in such a way (usually upwards) as to make the surface electrically neutral. With positive applied field, the thermodynamic equilibrium response is for the surface state bands to lift in energy above the bulk Fermi level, making electrons move out of the surface states. This leaves behind positive c ...
Electron Cooling Simulation for Arbitrary Distribution of Electrons
Electron Cooling Simulation for Arbitrary Distribution of Electrons

... possible versions of the electron cooling system design, and its accuracy is insufficient for a design of high energy electron coolers. Recently, modifications of the usual configuration of the low energy electron cooling system were proposed. To avoid instability of the ion beam related to an extre ...
Spontaneous Emission of an Excited Atom in a Dusty Unmagnetized
Spontaneous Emission of an Excited Atom in a Dusty Unmagnetized

... taking place under the action of the fluctuating field.” Spontaneous emission of light or luminescence is a fundamental process that plays an essential role in many phenomena in nature and forms the basis of many applications, such as fluorescent tubes, older television screens (cathode ray tubes), ...
ARcHNf. - DSpace@MIT
ARcHNf. - DSpace@MIT

... continuous-wave terahertz sources shows a lack of devices with power outputs of 1 W or greater between approximately 100 GHz and 10 THz. QCLs are represented by (s), frequency multipliers by (e) and other electronic devices by (-). Cryogenic results are plotted as hollow sym bols. . . . . . . . . . ...
Theory of relativistic electron holes in hot plasmas
Theory of relativistic electron holes in hot plasmas

... holes in the presence of the ion dynamics. A theoretical investigation [14] reveals the trapping and interactions between large-amplitude Langmuir waves and ion holes. The present status of the electron and ion hole physics as well as pertinent simulations and observations are contained in Ref. [15] ...
SIMULATION OF FIELD EMISSION FROM CARBON NANOTUBES USING
SIMULATION OF FIELD EMISSION FROM CARBON NANOTUBES USING

... ter scale [4] – is a multidisciplinary field of knowledge which pertains to any technology at the level of the nanoscale that can be utilized in the real world [4]. Owing to the very small length scale, which ranges from a couple of nanometers to a few micrometers, scientists have observed novel phy ...
Dust Visualisation in TJ-II with Intensified Visible Fast - Docu
Dust Visualisation in TJ-II with Intensified Visible Fast - Docu

ELECTRIC FIELD ENHANCEMENT FACTORS AROUND A
ELECTRIC FIELD ENHANCEMENT FACTORS AROUND A

... emission formula, such as the work function, φ, and screening from neighboring nanotubes that affects the local field. Systematic studies of the effect of the anode location for CNTs were performed by Smith et al.,14 but due to limitations of the software, the emitter was modeled as a parallelepiped cl ...
The Proton Radius Puzzle
The Proton Radius Puzzle

... we are seeing is a failure to recognize the charge field. It is an equation miss only in that none of the current equations include charge variations. They aren't including the charge field as a real field in either experiment, so they can't possibly include charge field variations between the two e ...
electron theory of metals
electron theory of metals

... metals, the Lorentz number varies with temperature at low temperatures. This is due to the fact all the electrons may not be participating in conduction process. W is the thermal conductivity of the metal. 4. Drude’s classical free electron theory totally failed to explain the conduction mechanism i ...
P6.3.1.1 - LD Didactic
P6.3.1.1 - LD Didactic

... visible light. The transitions are extremely rapid (< 10–5 s), so that fluorescence can only be observed during irradiation (in contrast to phosphorescence). ...
PPT
PPT

... b. increase the height of the barrier c. decrease the width of the barrier The frequency of the electron oscillating between the left and right well was too high  the probability to “tunnel” was too high! You can reduce this by increasing the barrier height. The wavelength of the emitted photon was ...
(Theory of electromagnetism and the light) Author: Arman
(Theory of electromagnetism and the light) Author: Arman

... and in the atom we mix this formula with the “Hock” law about the spring and after that we extension that to these formulas. We have in the Hock law that F=-k x and the negative mark of the law is for the third law of the Newton that when we enter a force to the spring it will enter a force as the s ...
Anisotropic growth of aluminum nitride nanostructures for a field
Anisotropic growth of aluminum nitride nanostructures for a field

... Anisotropic growth of aluminum nitride nanostructures for a field emission application Sang-Wook Ui and Sung-Churl Choi* Division of Materials Science & Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea One-dimensional single-crystalline AlN nanostructures, which ...
Adobe Acrobat Format ()
Adobe Acrobat Format ()

... (C3) The electric field inside a uniformly charged spherical shell is zero. True. Because of symmetry we know that if there were an electric field inside the shell it would be radial. But there is no charge inside the shell, so Gauss’s law gives Er = 0. Therefore the entire electric field must be ze ...
1 2 >

Field electron emission

Field emission (FE) (also known as field electron emission and electron field emission) is emission of electrons induced by an electrostatic field. The most common context is field emission from a solid surface into vacuum. However, field emission can take place from solid or liquid surfaces, into vacuum, air, a fluid, or any non-conducting or weakly conducting dielectric. The field-induced promotion of electrons from the valence to conduction band of semiconductors (the Zener effect) can also be regarded as a form of field emission. The terminology is historical because related phenomena of surface photoeffect, thermionic emission (or Richardson–Dushman effect) and ""cold electronic emission"", i.e. the emission of electrons in strong static (or quasi-static) electric fields, were discovered and studied independently from the 1880s to 1930s. When field emission is used without qualifiers it typically means ""cold emission"".Field emission in pure metals occurs in high electric fields: the gradients are typically higher than 1 gigavolt per metre and strongly dependent upon the work function. Electron sources based on field emission have a number of applications, but it is most commonly an undesirable primary source of vacuum breakdown and electrical discharge phenomena, which engineers work to prevent. Examples of applications for surface field emission include construction of bright electron sources for high-resolution electron microscopes or to discharge spacecraft from induced charges. Devices which eliminate induced charges are termed charge-neutralizers.Field emission was explained by quantum tunneling of electrons in the late 1920s. This was one of the triumphs of the nascent quantum mechanics. The theory of field emission from bulk metals was proposed by Ralph H. Fowler and Lothar Wolfgang Nordheim.A family of approximate equations, ""Fowler–Nordheim equations"", is named after them. Strictly, Fowler–Nordheim equations apply only to field emission from bulk metals and (with suitable modification) to other bulk crystalline solids, but they are often used – as a rough approximation – to describe field emission from other materials.In some respects, field electron emission is a paradigm example of what physicists mean by tunneling. Unfortunately, it is also a paradigm example of the intense mathematical difficulties that can arise. Simple solvable models of the tunneling barrier lead to equations (including the original 1928 Fowler–Nordheim-type equation) that get predictions of emission current density too low by a factor of 100 or more. If one inserts a more realistic barrier model into the simplest form of the Schrödinger equation, then an awkward mathematical problem arises over the resulting differential equation: it is known to be mathematically impossible in principle to solve this equation exactly in terms of the usual functions of mathematical physics, or in any simple way. To get even an approximate solution, it is necessary to use special approximate methods known in physics as ""semi-classical"" or ""quasi-classical"" methods. Worse, a mathematical error was made in the original application of these methods to field emission, and even the corrected theory that was put in place in the 1950s has been formally incomplete until very recently. A consequence of these (and other) difficulties has been a heritage of misunderstanding and disinformation that still persists in some current field emission research literature. This article tries to present a basic account of field emission ""for the 21st century and beyond"" that is free from these confusions.
  • studyres.com © 2025
  • DMCA
  • Privacy
  • Terms
  • Report