506:. At present, superconductors can only be achieved at very low temperatures, for instance by using cryogenic chilling. As yet, achieving superconductivity at room temperature remains challenging; it is still a field of ongoing research and experimentation. Creating a superconductor that functions at ambient temperature would constitute an important technological break-through, which could potentially contribute to much higher energy efficiency in grid distribution of electricity.
36:
379:). The recombination means an electron which has been excited from the valence band to the conduction band falls back to the empty state in the valence band, known as the holes. The holes are the empty states created in the valence band when an electron gets excited after getting some energy to pass the energy gap.
491:) by doping. Therefore, they will not act as double carriers by leaving behind holes (electrons) in the other band. In other words, charge carriers are particles that are free to move, carrying the charge. The free carrier concentration of doped semiconductors shows a characteristic temperature dependence.
308:
In some conductors, such as ionic solutions and plasmas, positive and negative charge carriers coexist, so in these cases an electric current consists of the two types of carrier moving in opposite directions. In other conductors, such as metals, there are only charge carriers of one polarity, so an
526:
and anti-taus may potentially also carry electric charge. This is theoretically possible, yet the very short life-time of these charged particles would render such a current very challenging to maintain at the current state of technology. It might be possible to artificially create this type of
449:
of the opposite type, where they are minority carriers. However, the traversing carriers hugely outnumber their opposite type in the transfer region (in fact, the opposite type carriers are removed by an applied electric field that creates an
303:
population of the semiconductor and are treated as charge carriers because they are mobile, moving from atom site to atom site. In n-type semiconductors, electrons in the conduction band move through the crystal, resulting in an electric
535:
Plasmas consists of ionized gas. Electric charge can cause the formation of electromagnetic fields in plasmas, which can lead to the formation of currents or even multiple currents. This phenomenon is used in
887:
479:. It is similar to the carrier concentration in a metal and for the purposes of calculating currents or drift velocities can be used in the same way. Free carriers are electrons (
210:, which are atoms or molecules that have gained or lost electrons so they are electrically charged. Atoms that have gained electrons so they are negatively charged are called
540:
reactors. It also occurs naturally in the cosmos, in the form of jets, nebula winds or cosmic filaments that carry charged particles. This cosmic phenomenon is called
912:
418:
with a donor impurity then the majority carriers are electrons. If the semiconductor is doped with an acceptor impurity then the majority carriers are holes.
717:
743:
502:
have zero electrical resistance and are therefore able to carry current indefinitely. This type of conduction is possible by the formation of
299:
with positive charge move through the crystal lattice, producing an electric current. The "holes" are, in effect, electron vacancies in the
860:
414:, which does not contain any impurity, the concentrations of both types of carriers are ideally equal. If an intrinsic semiconductor is
739:
454:), so conventionally the source and drain designation for the carriers is adopted, and FETs are called "majority carrier" devices.
131:
can exert force on these free particles, causing a net motion of the particles through the medium; this is what constitutes an
352:
346:
17:
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and these free carriers effectively vanish. The energy released can be either thermal, heating up the semiconductor (
78:
268:. When an electric field is applied strongly enough to draw the electrons into a beam, this may be referred to as a
451:
695:
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337:) as a second type of charge carrier, which carry a positive charge equal in magnitude to that of an electron.
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has p-type and n-type regions. The transistor action involves the majority carriers of the
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245:, and the sun and stars, the electrons and cations of ionized gas act as charge carriers.
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252:, free electrons can act as charge carriers. In the electronic component known as the
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electric current in them simply consists of charge carriers moving in one direction.
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display widely used in televisions and computer monitors until the 2000s.
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are electrolytic conductors employing positive hydrogen ions as carriers.
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893:. MIT Open CourseWare, Massachusetts Institute of Technology. p. 3
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current, or it might occur in nature during very short lapses of time.
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Dharan, Gokul; Stenhouse, Kailyn; Donev, Jason (May 11, 2018).
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they are holes. The less abundant charge carriers are called
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718:"Cation vs Anion: Definition, Chart and the Periodic Table"
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for an example of electrolysis of a melted ionic solid).
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In conducting media, particles serve to carry charge:
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There are two recognized types of charge carriers in
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of the metal. The free electrons are referred to as
888:"Lecture 4 - Carrier generation and recombination"
382:
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740:"Lecture 12: Proton Conduction, Stoichiometry"
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191:, and the cloud of free electrons is called a
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433:(FETs) is a bit more complex: for example, a
387:The more abundant charge carriers are called
796:"Vacuum Tubes: The World Before Transistors"
421:Minority carriers play an important role in
669:
817:"Cathode Rays | Introduction to Chemistry"
744:University of Illinois at Urbana–Champaign
395:transport in a piece of semiconductor. In
885:
670:Fitzpatrick, Richard (February 2, 2002).
445:regions, but these carriers traverse the
351:When an electron meets with a hole, they
79:Learn how and when to remove this message
509:
979:
913:"Majority and minority charge carriers"
715:
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1023:
886:del Alamo, JesĂşs (February 12, 2007).
861:"Carrier recombination and generation"
768:
696:"Conductors-Insulators-Semiconductors"
628:"Microscopic View of Electric Current"
391:, which are primarily responsible for
155:), of the same magnitude and opposite
982:"Back to the basics of power MOSFETs"
494:
483:) that have been introduced into the
56:Rework hook and remove bullet points.
793:
347:Carrier generation and recombination
341:Carrier generation and recombination
312:
29:
771:"Plasma conductivity and diffusion"
588:"Energy Education - Charge carrier"
363:in semiconductors), or released as
24:
980:Tulbure, Dan (February 22, 2007).
794:Alba, Michael (January 19, 2018).
769:SouÄŤek, Pavel (October 24, 2011).
716:Steward, Karen (August 15, 2019).
107:that is free to move, carrying an
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514:Under exceptional circumstances,
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399:they are electrons, while in
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859:Van Zeghbroeck, B. (2011).
650:"Conductors and Insulators"
551:
54:. The specific problem is:
10:
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839:"Intrinsic Semiconductors"
469:Free carrier concentration
461:
458:Free carrier concentration
344:
272:, and is the basis of the
206:, the charge carriers are
175:, the charge carriers are
145:elementary charge carriers
325:, which carry a negative
431:field-effect transistors
359:, one of the sources of
738:Ramesh Suvvada (1996).
412:intrinsic semiconductor
935:"Doped Semiconductors"
475:of free carriers in a
464:Charge carrier density
264:, by a process called
510:In quantum situations
401:p-type semiconductors
397:n-type semiconductors
369:optical recombination
357:thermal recombination
333:electron population (
301:valence-band electron
113:electrical conductors
377:semiconductor lasers
224:Hall–Héroult process
189:conduction electrons
179:. One or two of the
147:, each carrying one
61:improve this article
50:to meet Knowledge's
18:Free charge carriers
1005:"Carrier densities"
568:Molecular diffusion
477:doped semiconductor
423:bipolar transistors
293:effective particles
289:integrated circuits
266:thermionic emission
93:solid state physics
957:"Lecture 21: BJTs"
495:In superconductors
542:Birkeland current
405:minority carriers
389:majority carriers
313:In semiconductors
228:Proton conductors
185:crystal structure
181:valence electrons
149:elementary charge
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52:quality standards
43:This article may
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429:. Their role in
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500:Superconductors
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452:inversion layer
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327:electric charge
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115:. Examples are
109:electric charge
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546:plasma physics
538:nuclear fusion
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522:, anti-muons,
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462:Main article:
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345:Main article:
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319:semiconductors
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297:electron holes
281:semiconductors
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222:(see e.g. the
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97:charge carrier
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220:ionic solids
200:electrolytes
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563:Free charge
427:solar cells
295:" known as
285:transistors
270:cathode ray
254:vacuum tube
63:if you can.
1025:Categories
984:. EE Times
574:References
531:In plasmas
371:, used in
361:waste heat
243:neon signs
204:salt water
202:, such as
933:Nave, R.
837:Nave, R.
822:April 30,
801:April 30,
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754:April 30,
723:April 30,
701:April 30,
677:April 30,
655:April 30,
648:Nave, R.
633:April 30,
626:Nave, R.
593:April 30,
516:positrons
353:recombine
323:electrons
321:. One is
193:Fermi gas
177:electrons
117:electrons
1010:July 28,
552:See also
304:current.
171:In many
143:are the
139:and the
137:electron
101:particle
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471:is the
393:current
365:photons
262:cathode
216:cations
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988:May 2,
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918:May 2,
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871:May 1,
844:May 1,
439:source
435:MOSFET
410:In an
250:vacuum
235:plasma
212:anions
173:metals
141:proton
960:(PDF)
891:(PDF)
774:(PDF)
520:muons
481:holes
443:drain
416:doped
335:holes
258:valve
248:In a
233:In a
125:holes
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1012:2022
990:2021
967:2021
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524:taus
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441:and
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287:and
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