Editing Semiconductor (section)

== Properties ==

=== Variable electrical conductivity ===
Semiconductors in their natural state are poor conductors because a [[electric current|current]] requires the flow of electrons, and semiconductors have their [[valence band]]s filled, preventing the entire flow of new electrons. Several developed techniques allow semiconducting materials to behave like conducting materials, such as [[doping (semiconductor)|doping]] or [[field effect (semiconductor)|gating]]. These modifications have two outcomes: '''n-type''' and '''p-type'''. These refer to the excess or shortage of electrons, respectively. A balanced number of electrons would cause a current to flow throughout the material.<ref name="Neamen">{{cite book |last1=Neamen |first1=Donald A.|title=Semiconductor Physics and Devices |url=http://www.fulviofrisone.com/attachments/article/403/Semiconductor%20Physics%20And%20Devices%20-%20Donald%20Neamen.pdf|archive-url=https://web.archive.org/web/20221027123709/http://www.fulviofrisone.com/attachments/article/403/Semiconductor%20Physics%20And%20Devices%20-%20Donald%20Neamen.pdf|year=2003|archive-date=October 27, 2022 |publisher=Elizabeth A. Jones}}</ref>

=== Homojunctions ===
'''[[Homojunction]]s''' occur when two differently doped semiconducting materials are joined. For example, a configuration could consist of p-doped and n-doped [[germanium]]. This results in an exchange of electrons and holes between the differently doped semiconducting materials. The n-doped germanium would have an excess of electrons, and the p-doped germanium would have an excess of holes. The transfer occurs until an equilibrium is reached by a process called [[recombination (physics)|recombination]], which causes the migrating electrons from the n-type to come in contact with the migrating holes from the p-type.<ref>{{Cite web |date=2016-07-28 |title=Electron-Hole Recombination |url=https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Electronic_Properties/Electron-Hole_Recombination |access-date=2024-04-01 |website=Engineering LibreTexts |language=en}}</ref> The result of this process is a narrow strip of immobile [[ion]]s, which causes an [[electric field]] across the junction.<ref name="Feynman" /><ref name="Neamen"
 />

=== Excited electrons ===
A difference in electric potential on a semiconducting material would cause it to leave thermal equilibrium and create a non-equilibrium situation. This introduces electrons and holes to the system, which interact via a process called [[ambipolar diffusion]]. Whenever thermal equilibrium is disturbed in a semiconducting material, the number of holes and electrons changes. Such disruptions can occur as a result of a temperature difference or [[photon]]s, which can enter the system and create electrons and holes. The processes that create or annihilate electrons and holes are called [[carrier generation and recombination|generation]] and recombination, respectively.<ref name="Neamen" />

=== Light emission ===
In certain semiconductors, excited electrons can relax by emitting light instead of producing heat.<ref>By Abdul Al-Azzawi. "[https://books.google.com/books?id=Iw7NBQAAQBAJ&dq=In+certain+semiconductors,+excited+electrons+can+relax+by+emitting+light+instead+of+producing+heat.%5C&pg=PA54 Light and Optics: Principles and Practices]." 2007. March 4, 2016.</ref> Controlling the semiconductor composition and [[Electric current|electrical current]] allows for the manipulation of the emitted light's properties.<ref>{{Cite web |title=Electrical Property of Semiconductor - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/engineering/electrical-property-of-semiconductor |access-date=2023-12-14 |website=www.sciencedirect.com}}</ref> These semiconductors are used in the construction of [[light-emitting diode]]s and fluorescent [[quantum dot]]s.

===High thermal conductivity===
Semiconductors with high thermal conductivity can be used for heat dissipation and improving [[Thermal management (electronics)|thermal management]] of electronics. They play a crucial role in [[electric vehicle]]s, high-brightness [[Light-emitting diode|LEDs]] and [[power module]]s, among other applications.<ref>{{Citation |last1=Wang |first1=Yangang |title=Status and Trend of Power Semiconductor Module Packaging for Electric Vehicles |date=2016-10-05 |work=Modeling and Simulation for Electric Vehicle Applications |url=https://www.intechopen.com/chapters/51578 |access-date=2024-01-24 |publisher=IntechOpen |language=en |isbn=978-953-51-2637-9 |last2=Dai |first2=Xiaoping |last3=Liu |first3=Guoyou |last4=Wu |first4=Yibo |last5=Jones |first5=Yun Li and Steve}}</ref><ref>Arik, Mehmet, and Stanton Weaver. "Chip-scale thermal management of high-brightness LED packages." ''Fourth International Conference on Solid State Lighting''. Vol. 5530. SPIE, 2004.</ref><ref>{{Cite book |last1=Boteler |first1=L. |last2=Lelis |first2=A. |last3=Berman |first3=M. |last4=Fish |first4=M. |chapter=Thermal Conductivity of Power Semiconductors—When Does It Matter? |date=2019 |title=2019 IEEE 7th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) |chapter-url=https://ieeexplore.ieee.org/document/8998802 |publisher=IEEE |pages=265–271 |doi=10.1109/WiPDA46397.2019.8998802 |isbn=978-1-7281-3761-2|s2cid=211227341 }}</ref>

=== Thermal energy conversion ===
Semiconductors have large [[thermoelectric power factor]]s making them useful in [[thermoelectric generator]]s, as well as high [[thermoelectric figure of merit|thermoelectric figures of merit]] making them useful in [[thermoelectric cooler]]s.<ref>{{cite web |url=https://ii-vi.com/how_do_thermoelectric_coolers_tec_work/ |title=How do thermoelectric coolers (TECs) work? |website=ii-vi.com |access-date=2021-11-08}}</ref>