A dopant, also called doping agent and dope, is an impurity element added to a crystal or semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor.
Also, doping with Yb, Er, Nd, Tm, Cr of optical crystals, ceramics and glasses is used to make the solid-state lasers; the elements mentioned are the most common dopants. Erbium (ˈɝbiəm is a Chemical element with the symbol Er and Atomic number 68 Neodymium (ˌniːoʊˈdɪmiəm is a Chemical element with the symbol Nd and Atomic number 60 Thulium (ˈθjuːliəm is a Chemical element that has the symbol Tm and Atomic number 69 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 A solid-state laser is a Laser that uses a gain medium that is a Solid, rather than a Liquid such as in Dye lasers or a Gas In many optically-transparent ghosts, such active centers may keep their excitation for a time on the order of milliseconds, and relax with stimulated emission, providing the laser action. In Optics, stimulated emission is the process by which an electron perturbed by a Photon having the correct energy may drop to a lower Energy level resulting The amount of dopant is usually measured in atomic percent; usually the relative atomic percent is assumed, taking into account that the dopant ion can substitute the only part of site in a crystalline lattice. Atomic percent or at% is a measure of Concentration of Dopant, used in Chemistry, physics of Solid state lasers and Spectroscopy The doping can be also used to change the refraction index in optical fibers, especially in the double-clad fibers. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length In Fiber optics, a double-clad fiber (or doubly clad fiber or DCF is an Optical fiber that has a relatively small-diameter core and two layers The optical dopants are characterized with lifetime of excitation and the effective absorption and emission cross-sections, which are main parameters of an active dopant. Usually the concentration of optical dopant is of order of few percent or even lower. At large density of excitation, the cooperative quenching (cross-relaxation) reduces the efficiency of the laser action.
The process of introducing dopants into a semiconductor is called doping. In Semiconductor production doping is the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor to
The addition of a dopant to a semiconductor has the effect of shifting the Fermi level within the material. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that The Fermi energy is a concept in Quantum mechanics usually referring to the energy of the highest occupied Quantum state in a system of Fermions at This results in a material with predominantly negative (n type) or positive (p type) charge carriers depending on the dopant species. An N-type semiconductor (N for Negative) is obtained by carrying out a process of doping, that is by adding an impurity of valence -five elements to A P-type semiconductor (P for Positive) is obtained by carrying out a process of doping, that is adding a certain type of atoms to the semiconductor in order In Physics, a charge carrier denotes a free (mobile unbound particle carrying an Electric charge. Pure semiconductors altered by the presence of dopants are known as extrinsic semiconductors (cf. An extrinsic semiconductor is a Semiconductor that has been doped, that is into which a doping agent has been introduced giving it different electrical intrinsic semiconductor). An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure Semiconductor without any significant Dopant Dopants are introduced into semiconductors in a variety of techniques: solid sources, gases, spin on liquid and ion implanting. See ion implantation, surface diffusion, and solid sources footnote. Ion implantation is a Materials engineering process by which ions of a material can be implanted into another solid thereby changing the physical properties of the Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement