In the process of generation, a covalent bond is broken and a bound electron is transformed into a free electron. During recombination, the electron energy is released as a photon with the energy closed to the bandgap energy of the Solution: 15. In the semiconductor, free charge carriers are electrons and electron holes (electron-hole pairs). In the pair production process, an incident gamma ray of sufficiently high energy is annihilated in the Coulomb field of a nearby charged particle, resulting in the creation of an electron–positron pair. The force that drives electrons and holes through a circuit is created by the junction of two dissimilar semiconducting materials, one of which has a tendency to give up electrons… Electron-hole pairs are produced by (a) recombination (b) thermal energy (c) ionization (d) doping. Related electrical process: electron - hole pair recombination When the excited electron meets the hole in the valence band, it may occupy that place. (b) However, thermal energy can create few electron-hole pairs resulting in weak conduction. Answer to Electron-hole pairs are produced by(a) recombination(b) thermal energy(c) ionization(d) doping. III.A.3 Pair Production. The process of electron and hole annihilation is known as recombination. Electrons and holes are created by excitation of electron from valence band to the conduction band. As electron and hole are produced simultaneously, the process is called electron-hole pair generation. The result of light of sufficient energy dislodging an electron from its bond in a crystal, which creates a hole. An electron hole (often simply called a hole) is the lack of an electron at a position where one could exist in an atom or atomic lattice. These pairs are the constituents of electricity. (a) An intrinsic semiconductor is an insulator having a complete electron shell. The electrons are called the majority carriers in n-type material. As a result the e-h pair disappear; this process is called recombination. These holes are not produced by the addition of the pentavalent impurity atoms. Both carriers eventually disappear in the process. Thermal energy may occasionally free an electron from the crystal lattice as in Figure above (b). View Answer: Answer: Option B. n i is produced by a dynamic process; free electron hole pairs are continually being generated, while other electron hole pairs are recombining Thermal energy is one of the agents which causes pair generation. The free electron (negative charge) and the hole (positive charge) are a pair. J.Gregory Stacy, W.Thomas Vestrand, in Encyclopedia of Physical Science and Technology (Third Edition), 2003. Another agent is optical illumination. If the energy released through recombination is in the form of a photon, the process is known as radiative-recombination and is most common for electrons moving fully from the conduction to the valence band. free-electron concentration is equal to hole concentration (whole pure Si crystal is charge neutral), and either one is represented by the symbol n i, which is called the intrinsic carrier concentration. This electron is free for conduction about the crystal lattice. Other articles where Electron-hole pair is discussed: materials science: Photovoltaics: The electron motion, and the movement of holes in the opposite direction, constitute an electric current. Although the majority of current carriers in n-type material are electrons, there are also a few holes that are created when electron-hole pairs are thermally generated. 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