Dopant

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Dopant

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

Ytterbium

Ytterbium is a chemical element with the symbol Yb and atomic number 70. A soft silvery metallic element, ytterbium is a Rare earth element of the lanthanide series and is found in the minerals gadolinite, monazite, and xenotime....
, Er

Erbium

Erbium is a chemical element with the symbol Er and atomic number 68. A rare, silvery, white metallic lanthanide, erbium is solid in its normal state....
, Nd

Neodymium

Neodymium is a chemical element with the symbol Nd and atomic number 60....
, Tm

Thulium

Thulium is a chemical element that has the symbol Tm and atomic number 69. A lanthanide element, thulium is the least abundant of the Rare earth elements....
, Cr

Chromium

Chromium is a chemical element which has the symbol Cr and atomic number 24. It is a steely-gray, Lustre , hard metal that takes a high polish and has a high melting point....
of optical crystals, ceramics and glasses is used to make the solid-state laser

Solid-state laser

A solid-state laser is a laser that uses a active laser medium that is a solid, rather than a liquid such as in dye lasers or a gas as in gas lasers....
s; the elements mentioned are the most common dopants. 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

Stimulated emission

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 in the creation of another photon....
, providing the laser action.

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Why we do not dope silicon with group 2 and group 6 elements of periodic table.

Encyclopedia

Ytterbium

Erbium

Erbium is a chemical element with the symbol Er and atomic number 68. A rare, silvery, white metallic lanthanide, erbium is solid in its normal state....
, Nd

Neodymium

Neodymium is a chemical element with the symbol Nd and atomic number 60....
, Tm

Thulium

Thulium is a chemical element that has the symbol Tm and atomic number 69. A lanthanide element, thulium is the least abundant of the Rare earth elements....
, Cr

Chromium

Solid-state laser

Stimulated emission

Atomic percent

Atomic percent or at.% is a measure of concentration of dopant, used in chemistry, physics of solid state lasers and spectroscopy.The meaning of this term strongly depends on the context, host material and dopant....
; 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. The doping can be also used to change the refraction index in optical fibers, especially in the double-clad fiber

Double-clad fiber

In fiber optics, a double-clad fiber is an optical fiber that has a relatively small-diameter Fiber optics#Principle of operation and two layers of large-diameter cladding....
s. The optical dopants are characterized with lifetime

Lifetime

selfref|For Wikipedia's Lifetime template, see Wikipedia:...
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

Doping (semiconductor)

In semiconductor production, doping is the process of intentionally introducing impurities into an extremely pure semiconductor to change its electrical properties....
.

The addition of a dopant to a semiconductor

Semiconductor

A semiconductor is a material that has electrical conductivity between those of a Electrical conductor and an electrical insulation; it can vary over that wide range either permanently or dynamically....
has the effect of shifting the Fermi level within the material. This results in a material with predominantly negative (n type

N-type semiconductor

An N-type semiconductor is obtained by carrying out a process of Doping , that is, by adding an impurity of Valence -five elements to a valence-four semiconductor in order to increase the number of free charge carriers ....
) or positive (p type

P-type semiconductor

A P-type semiconductor is obtained by carrying out a process of Doping , that is adding a certain type of atoms to the semiconductor in order to increase the number of free charge carriers ....
) charge carrier

Charge carrier

In physics, a charge carrier denotes a free particle carrying an electric charge. Examples are electrons and ions.In ionic solutions, the charge carriers are the dissolved cations and anions....
s depending on the dopant species. Pure semiconductors altered by the presence of dopants are known as extrinsic semiconductor

Extrinsic semiconductor

An extrinsic semiconductor is a semiconductor that has been doped, that is, into which a Dopant has been introduced, giving it different electrical properties than the Intrinsic semiconductor....
s (cf. intrinsic semiconductor

Intrinsic semiconductor

An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present....
). Dopants are introduced into semiconductors in a variety of techniques: solid sources, gases, spin on liquid and ion implanting. See ion implantation

Ion implantation

Ion implantation is a materials engineering process by which ion s of a material can be implanted into another solid, thereby changing the physical properties of the solid....
, surface diffusion

Diffusion

Molecular diffusion, often called simply diffusion, is a net transport of molecules from a region of higher concentration to one of lower concentration by random molecular motion....
, and solid sources footnote.

Examples

Boron
Boron

Boron is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent metalloid element which occurs abundantly in the evaporite ores borax and ulexite....
, arsenic
Arsenic

Arsenic is a well-known chemical element that has the symbol As and atomic number 33. Arsenic was first documented by Albertus Magnus in 1250....
, phosphorus
Phosphorus

Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the and . A Valency nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate minerals....
, antimony
Antimony

Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropy forms. The stable form of antimony is a blue-white metalloid....
, among other substances, are commonly used dopants in the semiconductor industry.

Dopants for silicon
Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
and germanium
Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, greyish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon....
, group IV
Group 4 element

In modern IUPAC nomenclature, Group 4 of the periodic table contains the following chemical elements:* titanium * zirconium * hafnium * rutherfordium ....
semiconductors:

Donors: group V
Group 5 element

A Group 5 element is one in the chemical series of Chemical element in periodic table group in the periodic table, which consists of vanadium , niobium , tantalum , and dubnium ....
atoms: antimony
Antimony

Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropy forms. The stable form of antimony is a blue-white metalloid....
, phosphorus
Phosphorus

Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the and . A Valency nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate minerals....
, arsenic
Arsenic

Arsenic is a well-known chemical element that has the symbol As and atomic number 33. Arsenic was first documented by Albertus Magnus in 1250....
Acceptors: group III
Group 3 element

|-| Period 5 element |||-||| Group number of lanthanides and actinides|-||||-||||-| Period 6 element || *Lanthanides|-| Period 7 element || **Actinides...
atoms: boron
Boron

Boron is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent metalloid element which occurs abundantly in the evaporite ores borax and ulexite....
, aluminium
Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
, gallium
Gallium

Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the Ga salt, in trace amounts in bauxite and zinc ores....

Dopants for gallium arsenide, a group III-V semiconductor:

Donors: group VI
Group 6 element

A Group 6 element is one in the chemical series of Chemical element in periodic table group in the periodic table, which consists of the transition metals chromium , molybdenum , tungsten , and seaborgium ....
and group IV
Group 4 element

In modern IUPAC nomenclature, Group 4 of the periodic table contains the following chemical elements:* titanium * zirconium * hafnium * rutherfordium ....
atoms: sulfur
Sulfur

Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant Valence non-metal....
, selenium
Selenium

Selenium is a chemical element with the atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature....
, tellurium
Tellurium

Tellurium is a chemical element that has the symbol Te and atomic number 52. A brittle silver-white metalloid which looks like tin, tellurium is chemically related to selenium and sulfur....
, silicon
Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
Acceptors: group II and group IV
Group 4 element

In modern IUPAC nomenclature, Group 4 of the periodic table contains the following chemical elements:* titanium * zirconium * hafnium * rutherfordium ....
atoms: magnesium
Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....
, zinc
Zinc

Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
, cadmium
Cadmium

Cadmium is a chemical element with the symbol Cd and atomic number 48. A relatively abundant , soft, bluish-white, transition metal, cadmium is known to cause cancer and occurs with zinc ores....
, silicon
Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....

The medical field has some use for erbium
Erbium

Erbium is a chemical element with the symbol Er and atomic number 68. A rare, silvery, white metallic lanthanide, erbium is solid in its normal state....
in as a dopant for lasers used in surgery. Europium
Europium

Europium is a chemical element with the symbol Eu and atomic number 63. It was named after the continent Europe.Characteristics ...
is used to dope plastics in lasers. Holmium
Holmium

Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a relatively soft and malleable silvery-white metallic element, which is stable in dry air at room temperature....
is used as to dope Yttrium
Yttrium

Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanoids and has historically been classified as a rare earth element....
-Aluminium
Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
Garnets used in laser surgery. (Source: Strategic Rare Earth Metals Inc.) Neodymium
Neodymium

Neodymium is a chemical element with the symbol Nd and atomic number 60....
doped optical materials are used frequently in the very common neodymium lasers.
Artificially produced gemstone
Gemstone

A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive mineral, which — when cut and polished — is used to make jewellery or other adornments....
s (such as rubies
Ruby

A ruby is a pink to blood-red gemstone, a variety of the mineral corundum . The red color is caused mainly by the presence of the element chromium....
) sometimes contain a dopant to identify them as such.

Dopant

Examples

See also