In this physics digital electronics video lecture in hindi for class 12 we described different type of semiconductor intrinsic and extrinsic. Semiconductors, diodes, transistors horst wahl, quarknet presentation, june 2001 electrical conductivity. Examples of pentavalent impurities are phosphorus or. P type and n type semiconductor majority and minority. Ntype semiconductors are a type of extrinsic semiconductor where the dopant. Extrinsic semiconductor is of two types p type and. Jul 29, 2017 p type semiconductors this type of semiconductor is obtained when traces of a trivalent impurity like boron b are added to a pure germanium crystal. The types of doped semiconductors formed after the addition of the impurity are. A solid state diode consists of ptype and ntype semiconductors placed side by side. Photoelectrochemical experiments show that the cu 2 o thin films synthesized in acid and alkaline or neutral media present n type and p type semiconductor character, respectively. Difference between n type semiconductor and p type semiconductor we have already discussed about the concept of semiconductors, their types. When the trivalent impurity is added to an intrinsic or pure semiconductor silicon or germanium, then it is said to be an p type semiconductor.
A semiconductor diode devices that allow current in only one direction consists of ptype and ntype semiconductors placed in junction with one another. In the top part of the above diagram we see that if the negative end of the battery is attached to the ntype side of the diode, incoming electrons will dislodge the. Semiconductors can be broadly classified into intrinsic and extrinsic semiconductors. Doped semiconductors ntype materials ptype materials diodes and transistors. Another difference is that whereas the fermi level of intrinsic semiconductors is somewhere midway between the valence band and the conduction band, it shifts upwards in case of ntype while it drifts downward in case of ptype due to obvious reasons. A semiconductor which is pure and contains no impurity is known as an intrinsic semiconductor. Impurities introduce discrete, noninteracting donor and acceptor energy states in an n type and ptype semiconductor, respectively. However, the fifth electron remains loosely bound to the parent atom. The density of electrons and holes, energy level and fermi level, the direction of movement of majority carriers, etc.
Types of doped semiconductors there are two different ways of adding an impurity to the semiconductor atom. The semiconductor materials used in electronic devices are doped under precise conditions to control the concentration and regions of p and ntype dopants. Semiconductors ppt and pdf report free study mafia. Apr 10, 2020 the majority carrier for the p type would be positive and the minority negative. Photoelectrochemical experiments show that the cu 2 o thin films synthesized in acid and alkaline or neutral media present ntype and ptype semiconductor character, respectively. A unique feature of the semiconductors is that they are bipolar in nature and in them, the current is transported by the electrons and holes. We also acknowledge previous national science foundation support under grant numbers 1246120, 1525057, and 14739. Jun, 2018 semiconductors are used extensively in the electronics industry and in electronic circuits.
Trivalent impurities such as boron b, gallium g, indiumin, aluminiumal etc are called acceptor impurity. The extrinsic p type semiconductor is formed when a trivalent impurity is added to a pure semiconductor in a small amount, and as a result, a large number of holes are created in it. Pdf intrinsic ntype versus ptype doping asymmetry and the. Difference between n type and p type semiconductors. The trivalent impurity used for doping purpose of a p type semiconductor are boron, gallium, and indium. The p type and n type are two different types of semiconductors. The doping of semiconductors georgia state university. They are mainly classified into two types as follows. However, in an ntype semiconductor, the density of states increases, therefore, accommodating more electrons at higher energy levels. Pure tetravalent substance is known as intrinsic semiconductoe and some impurity is mixed with that pure substance, it. A large number of holes are provided in the semiconductor material by the addition of trivalent impurities like gallium and indium. Extrinsic semiconductors are components of many common electrical devices. Semiconductor type intrinsic extrinsic ptype ntype. These are ptype and ntype semiconductors brought together in close contact, creating what is called the depletion region.
Semiconductors are used extensively in the electronics industry and in electronic circuits. A semiconductor diode devices that allow current in only one direction consists of p type and n type semiconductors placed in junction with one another. Since semiconductors are generally poor conductors, their conductivity can be drastically increased by the controlled addition of impurities to the intrinsic pure p. When a doped semiconductor contains mostly free holes it is called ptype, and when it contains mostly free electrons it is known as ntype. Similarly, the n type has a larger electron concentration. An important application of this is the p n junction, where p type and n type semiconductors are brought into close contact. The importance of this contact or junction is the creating of a region between the p and n layers where ptype holes can recombine with ntype free electrons producing light, such as in light emitting diodes leds. What is the difference between ntype and ptype semiconductor. Keep in mind that silicon is valence iv four ntype silicon when a silicon atom in the crystal lattice is. A compound semiconductor is a semiconductor compound composed of chemical elements of at least two different species. Neither pure siliconsi nor germaniumge are great conductors. In this chapter, we will restrict ourselves to the study of inorganic semiconductors, particularly. Apr 27, 2020 ntype and ptype semiconductors class 12 notes edurev is made by best teachers of class 12. The difference between a p type semiconductor and n type semiconductor are given below in tabulated form.
A p type semiconductor is one with a preponderance of holes. This document is highly rated by class 12 students and has been viewed 2639 times. When pentavalent impurity uses for doping then it creates extra electrons in a semiconductor called n type semiconductor or donor. In a ptype semiconductor, there is an increase in the density of unfilled states. In the top part of the above diagram we see that if the negative end of the battery is attached to the n type side of the diode, incoming electrons will dislodge the.
By doping, semiconductors can be produced with different and complementary conductive properties. In ntype semiconductor material, the number of electrons increases, compared to the available number of charge carriers in the intrinsic semiconductor. This chapter covers the fundamentals of conduction in semiconductors. A doped semiconductor as opposed to an intrinsic semiconductor is one that has had specific impurity atoms introduced into it to shrink the band gap. An important application of this is the pn junction, where ptype and ntype semiconductors are. The extrinsic ptype semiconductor is formed when a trivalent impurity is added to a pure semiconductor in a small amount, and as a result, a large number of holes are created in it. The p type carries a positive charge, while the n type carries a negative charge. Because there are many more electrons than holes in ntype material, electrons are said to be the majority charge carriers, and holes are said to be minority carriers in ntype material. These are p type and n type semiconductors brought together in close contact, creating what is called the depletion region.
When the trivalent impurity is added to an intrinsic or pure semiconductor silicon or germanium, then it is said to be an ptype semiconductor. In ptype material, holes are the majority carriers and electrons are. P type and n type semiconductor both are extrinsic semiconductors. Pdf zno typifies a class of materials that can be doped via native defects in only one way. When it comes to semiconductors, silicon is the most common material used. A barrier forms along the boundary between ptype and ntype semiconductors that is known as a pn junction. The pentavalent elements are called so as they have 5 electrons in their valence shell. These semiconductors typically form in periodic table groups 15 old groups iiiv, for example of elements from the boron group old group iii, boron, aluminium, gallium, indium and from group 15 old group v, nitrogen, phosphorus, arsenic, antimony, bismuth. Hence, the number of free electrons in a ptype semiconductor is much smaller than the number of holes in it. The trivalent impurity used for doping purpose of a ptype semiconductor are boron, gallium, and indium. Each type of atom has a certain number of electrons and protons that distinguishes it from the atoms of all. The doping of semiconductors the addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing ntype and ptype semiconductors pentavalent impurities impurity atoms with 5 valence electrons produce ntype semiconductors by contributing extra electrons. The various factors like doping element, nature of doping element, the majority and minority carriers in the ptype and ntype semiconductor.
Oct 23, 2017 because there are many more electrons than holes in n type material, electrons are said to be the majority charge carriers, and holes are said to be minority carriers in n type material. The semiconductor materials used in electronic devices are doped under precise conditions to control the concentration and regions of p and n type dopants. The semiconductors have the conductivity which is between the conductors and the insulators. In p type semiconductor trivalent impurity is added. Jul 06, 2016 since semiconductors are generally poor conductors, their conductivity can be drastically increased by the controlled addition of impurities to the intrinsic pure p. Mar 16, 2019 based on the dopants used the extrinsic semiconductors are further classified as ntype semiconductor and p type semiconductor. The majority carrier for the ptype would be positive and the minority negative. Difference between p type and n type semiconductor circuit globe. In p type material, holes are the majority carriers and electrons are minority carriers.
The two categories of impurities are ntype and ptype. The importance of this contact or junction is the creating of a region between the p and n layers where p type holes can recombine with n type free electrons producing light, such as in light emitting diodes leds. Ptype semiconductor is formed by adding trivalent impurities and ntype semiconductor is formed by adding pentavalent impurities in the semiconductor. Difference between p type and n type semiconductor. Sep 23, 2017 apr 27, 2020 n type and p type semiconductors class 12 notes edurev is made by best teachers of class 12. Difference between n type and p type semiconductor quick. However, after 1990, a few semiconductor devices using organic semiconductors and semiconducting polymers have been developed signalling the birth of a futuristic technology of polymerelectronics and molecularelectronics. However, in an n type semiconductor, the density of states increases, therefore, accommodating more electrons at higher energy levels.
Based on the dopants used the extrinsic semiconductors are further classified as ntype semiconductor and p type semiconductor. Group v elements such as phosphorus, antimony and arsenic are usually classified as ntype impurities. In order to understand the operation of these devices, the basic mechanism of how currents. That is why we consider holes as majority carriers, and electrons are called minority carriers in a ptype semiconductor. When a doped semiconductor contains mostly free holes it is called p type, and when it contains mostly free electrons it is known as n type. They form a crystal lattice by having each atom share all of its 4. Diodes only allow electricity to flow in one direction through them.
Currently, most semiconductor diodes use doped silicon or germanium. Trivalent impurities such as boron b, gallium ga, indium in, aluminium al etc are called acceptor impurity. Jul 30, 2017 in this physics digital electronics video lecture in hindi for class 12 we described different type of semiconductor intrinsic and extrinsic. Based on the type of doping material incorporated, semiconductor crystals are classified into two types particularly ntype semiconductors and ptype semiconductors. An ntype semiconductor is one that has been doped with a pe. Keep in mind that silicon is valence iv four ntype silicon when a silicon atom in the crystal lattice is replaced with a valence v five atom such as. Ptype semiconductors this type of semiconductor is obtained when traces of a trivalent impurity like boron b are added to a pure germanium crystal. The ntype semiconductors are doped with pentavalent impurities. The p type semiconductor has a larger hole concentration, which results in the positive charge. Ptype, ntype semiconductors engineering libretexts. That is why we consider holes as majority carriers, and electrons are called minority carriers in a p type semiconductor. Difference between n type semiconductor and p type.
Intrinsic semiconductor and extrinsic semiconductor. Apr 01, 2019 these impurity atoms are known as dopants. If a silicon or germanium atom in its pure form is doped with an element of group. The addition of trivalent impurity creates large number of holes in the valence band. An n type semiconductor is one that has been doped with a pe. We can also refer to this as a difference between electron donor and acceptor. The resultant material is known as an ntype semiconductor. A solid state diode consists of p type and n type semiconductors placed side by side.
In our article on semiconductors, we discussed that semiconductors are amorphous or crystalline solids that have a conductivity between that of a conductor and an insulator, either due to the presence of an impurity extrinsic semiconductors or because of temperature change. Because electrons under ordinary conditions will flow in only one direction through such barriers, pn junctions form the basis for creating electronic rectifiers and switches. N type and p type semiconductors engineering tutorial. In ptype semiconductor trivalent impurity is added. Mar 15, 2020 hence, the number of free electrons in a p type semiconductor is much smaller than the number of holes in it. This process, called doping, increases the number of current carriers electrons or holes. Ptype semiconductor simple english wikipedia, the free. The two categories of impurities are n type and p type. Extrinsic semiconductor is of two types ptype and ntype semiconductor. Lets take a look at the difference between an ntype and ptype semiconductor. Ntype and ptype semiconductors class 12 notes edurev.
The doping of semiconductors the addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n type and p type semiconductors pentavalent impurities impurity atoms with 5 valence electrons produce n type semiconductors by contributing extra electrons. Fifth electron is superfluous, becomes free electron and enters into conduction band. Each added boron atom creates a deficiency of one electronthat is, a positive hole. Difference between p type and n type semiconductor p. Each trivalent impurity creates a hole in the valence band and ready to accept an electron. When a small amount of impurity is added to a pure semiconductor. The difference between p type and n type semiconductor are based on various factors like nature of doping element, majority and minority carriers etc. The difference between a ptype semiconductor and ntype semiconductor are given below in tabulated form.
We can define p type and n type semiconductor by their impurities added. Although the free electrons and holes drift in opposite directions, the current. P type for excess positive charges silicon results if the dopant is boron, which contains one electron fewer than a silicon atom. Apr 30, 2016 in n type semiconductor material, the number of electrons increases, compared to the available number of charge carriers in the intrinsic semiconductor. Depending on the type of doping material used, extrinsic semiconductors can be subdivided into two classes. Thus, accommodating more electrons at the lower energy levels. In this case,the three valence electrons of boron atom from covalent bonds with four surrounding germanium atoms,but one bond is left incomplete and gives rise to a hole. Jun 16, 2017 semiconductors ppt and pdf report free. The charges depend on the hole concentration and the electron concentration. Semiconductors types, examples, properties, application. In a p type semiconductor, there is an increase in the density of unfilled states.