N-type semiconductor

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N-type semiconductor

An N-type semiconductor (N for Negative) is obtained by carrying out a process of doping, that is, by adding an impurity of valence

Valence (chemistry)

In chemistry, valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given chemical element....
-five elements to a valence-four 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....
in order to increase the number of free 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 (in this case negative).

When the doping material is added, it gives away (donates) weakly-bound outer electron

Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
s to the semiconductor atoms. This type of doping agent is also known as donor material since it gives away some of its electrons.

The purpose of N-type doping is to produce an abundance of mobile or "carrier" electrons in the material.

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Encyclopedia

An N-type semiconductor (N for Negative) is obtained by carrying out a process of doping, that is, by adding an impurity of valence

Valence (chemistry)

Semiconductor

Charge carrier

Electron

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....
(Si). Si atoms have four valence electron

Valence electron

In science, valence electrons are the electrons contained in the outermost, or valence, electron shell of an atom. Valence electrons are important in determining how an chemical element reacts chemically with other elements: The fewer valence electrons an atom holds, the less reactivity it becomes and the more likely it is to chemical rea...
s, each of which is covalently bonded

Covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds....
with each of the four adjacent Si atoms. If an atom with five valence electrons, such as those from group 15 (old group VA, a.k.a. nitrogen group

Nitrogen group

The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
) of the periodic table

Periodic table

The periodic table of the chemical elements is a table method of displaying the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869....
(eg. 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....
(P), 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....
(As), or 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....
(Sb)), is incorporated into the crystal lattice in place of a Si atom, then that atom will have four covalent bonds and one unbonded electron. This extra electron is only weakly bound to the atom and can easily be excited into the conduction band

Conduction band

In the physics field of semiconductors and Electrical insulations, the conduction band is the range of electron energy, higher than that of the valence band, sufficient to make the electrons free to accelerate under the influence of an applied electric field and thus constitute an electric current....
. At normal temperatures, virtually all such electrons are excited into the conduction band

Conduction band

In the physics field of semiconductors and Electrical insulations, the conduction band is the range of electron energy, higher than that of the valence band, sufficient to make the electrons free to accelerate under the influence of an applied electric field and thus constitute an electric current....
. Since excitation of these electrons does not result in the formation of a hole

Electron hole

An electron hole is the conceptual and mathematical opposite of an electron, useful in the study of physics and chemistry. The concept describes the lack of an electron....
, the number of electrons in such a material far exceeds the number of holes. In this case the electrons are the majority carriers and the holes are the minority carriers. Because the five-electron atoms have an extra electron to "donate", they are called donor

Donor (semiconductors)

In semiconductors physics the term donor is used to generically indicate a Semiconductors#Dopants atom that added to a semiconductor can form n-type regions....
atoms. Note that each movable electron within the semiconductor is never far from an immobile positive dopant ion, and the N-doped material normally has a net electric charge

Electric charge

Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields....
of zero.

In an N-type semiconductor, the fermi level lies closer to the conduction band edge.

N-type semiconductor

See also