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  2. Space charge - Wikipedia

    en.wikipedia.org/wiki/Space_charge

    Space charge is an inherent property of all vacuum tubes. This has at times made life harder or easier for electrical engineers who used tubes in their designs. For example, space charge significantly limited the practical application of triode amplifiers which led to further innovations such as the vacuum tube tetrode.

  3. Franck–Hertz experiment - Wikipedia

    en.wikipedia.org/wiki/Franck–Hertz_experiment

    At low potential differences—up to 4.9 volts—the current through the tube increased steadily with increasing potential difference. This behavior is typical of true vacuum tubes that don't contain mercury vapor; larger voltages lead to larger "space-charge limited current". At 4.9 volts the current drops sharply, almost back to zero.

  4. Depletion region - Wikipedia

    en.wikipedia.org/wiki/Depletion_region

    In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region, or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have diffused away, or been forced away by an electric field. The only elements left ...

  5. Band diagram - Wikipedia

    en.wikipedia.org/wiki/Band_diagram

    The primary principle underlying band bending inside a semiconductor is space charge: a local imbalance in charge neutrality. Poisson's equation gives a curvature to the bands wherever there is an imbalance in charge neutrality. The reason for the charge imbalance is that, although a homogeneous material is charge neutral everywhere (since it ...

  6. Theory of solar cells - Wikipedia

    en.wikipedia.org/wiki/Theory_of_solar_cells

    When the pair is created outside the space charge zone, where the electric field is smaller, diffusion also acts to move the carriers, but the junction still plays a role by sweeping any electrons that reach it from the p side to the n side, and by sweeping any holes that reach it from the n side to the p side, thereby creating a concentration ...

  7. Field effect (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Field_effect_(chemistry)

    A field effect is the polarization of a molecule through space. The effect is a result of an electric field produced by charge localization in a molecule. [ 1 ] This field, which is substituent and conformation dependent, can influence structure and reactivity by manipulating the location of electron density in bonds and/or the overall molecule ...

  8. Casimir effect - Wikipedia

    en.wikipedia.org/wiki/Casimir_effect

    In quantum field theory, the Casimir effect (or Casimir force) [1] is a physical force acting on the macroscopic boundaries of a confined space which arises from the quantum fluctuations of a field. The term Casimir pressure is sometimes used when it is described in units of force per unit area.

  9. Electric-field screening - Wikipedia

    en.wikipedia.org/wiki/Electric-field_screening

    In solid-state physics, especially for metals and semiconductors, the screening effect describes the electrostatic field and Coulomb potential of an ion inside the solid. Like the electric field of the nucleus is reduced inside an atom or ion due to the shielding effect , the electric fields of ions in conducting solids are further reduced by ...