Opto ppt
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This document discusses optical emission from semiconductors. It explains that intrinsic semiconductors contain no impurities, while extrinsic semiconductors are made by doping with impurities to add electrons or holes. The probability that an electron occupies an energy level is given by the Fermi-Dirac distribution. A p-n junction diode is formed by creating adjoining p- and n-type semiconductor layers. A depletion region forms at the junction through carrier recombination, establishing a potential barrier. Under certain conditions in semiconductors, carrier recombination occurs with the emission of light.
Opto ppt
- 1. Optical Emission From Semiconductor Md Presented Manzar By Nezami
- 2. Point Of Discussion Explain with the help of energy band structure, the process of optical emission from semiconductor.
- 3. To allow consideration of semiconductor optical sources it is necessary to review some of the properties of semiconductor materials, especially with regard to p-n junction.
- 4. semiconductor Intrinsic Extrinsic
- 5. Intrinsic Semiconductor: A perfect semiconductor crystal containing no impurities and lattice effect. Extrinsic Semiconductor: A semiconductor crystal which is made up by the process of doping, i.e. adding impurity to it.
- 7. For a semiconductor in thermal equilibrium the energy level occupation is described by fermi dirac distribution function. Consequently the probability p(E) that an electron gains sufficient thermal energy at an absolute temperature T such that it will be found occupying a particular energy level E, is given by the fermi-dirac distribution. P(E)=1/{1+exp(E-Ef )/kT}
- 9. • To create an extrinsic semicondutor the material is doped with impurity atoms which creates either more free electrons (donor impurity) or holes(acceptor impurity)
- 11. The p-n junction diode The p-n junction diode is formed by creating adjoining p and n type semiconductor layers in single crystal. A thin depletion region is formed at the junction through carrier recombination. This establishes a potential barrier between the p and n type regions which restricts the inter diffusion of majority carriers from their respective regions. An external applied voltage form current flow through the device as they continuously diffuse away from the interface. However, this situation in suitable semiconductor allows carrier recombination with the emission of light.