EXCITONS Meaning and
Definition
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Excitons are quasi-particles that arise due to the interaction of an electron with an electron hole (a lack of an electron in an atom or crystal lattice) in a solid material. Excitons are often observed in semiconductors or insulators, where electrons are restricted to a certain energy band and there are energy gaps between different bands.
When an electron absorbs energy, it can be promoted from the valence band (band where electrons reside in the ground state) to the conduction band (higher energy band where electrons can move more freely). This leaves behind an electron hole in the valence band. The electron-hole pair can become bound together by their mutual electrostatic attraction, forming the exciton.
The exciton behaves as a single entity, with the electron and hole continually orbiting each other due to Coulomb forces. These orbiting motions give rise to characteristic energy levels or exciton states, which can have different energies and angular momenta based on the relative motion of the electron and hole.
Excitons are important in several optical and electronic phenomena. They can absorb and emit light when transitioning between different energy levels. The recombination of excitons, where the electron recombines with the hole, can emit photons and form the basis of light-emitting devices such as LEDs. Additionally, excitons can also affect the electrical properties of materials, influencing energy transport and charge generation processes in solar cells or photovoltaics.
Common Misspellings for EXCITONS
Etymology of EXCITONS
The word "exciton" was coined in the 1930s by Russian physicist Yakov Frenkel, who is credited with laying the foundation for the theory of excitons. Frenkel derived the term from the Greek word "excite" (meaning "to excite" or "to rouse") and added the ending "-on" to denote a particle or entity. Thus, "exciton" refers to an excited state of an electron in a solid, indicating an excited electron-hole pair generated by the absorption of light or energy.
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