By doping pure silicon with Group V elements such as phosphorus, extra valence electrons are added that become unbonded from individual atoms and allow the compound to be an electrically conductive n-type semiconductor.

When germanium is doped with phosphorus, the doped material has more negative current carriers.

For example, germanium (Ge) and Silicon (Si) have four valence electrons known as tetravalent elements are the most common type of intrinsic semiconductor materials. Given, (i) Ge is tetravalent, and In is a trivalent element. When Ge is doped with In, the p-type semiconductor is obtained.

Therefore the number of electrons increases when phosphorous is added as an impurity. So n-type extrinsic semiconductor is formed.

p-type and n-type materials are simply semiconductors, such as silicon (Si) or germanium (Ge), with atomic impurities; the type of impurity present determines the type of the semiconductor.

Electrons provide most of the current and are called the majority carrier. When the majority carrier is negative, the material is known as an n-type semiconductor. Since the phosphorus atom has “donated” an electron to the conduction band, phosphorus is called the donor material.

For example, when silicon (Si), having four valence electrons, needs to be doped as a n-type semiconductor, elements from group V like phosphorus (P) or arsenic (As) can be used because they have five valence electrons. A dopant with five valence electrons is also called a pentavalent impurity.

Elements like phosphorus, antimony, bismuth, arsenic etc. are donor impurities.

n-type Semiconductors Since silicon is a tetravalent element, the normal crystal structure contains 4 covalent bonds from four valence electrons. In silicon, the most common dopants are group III and group V elements. Group V elements (pentavalent) have five valence electrons, which allows them to act as a donor.

Doping is the key to the extraordinarily wide range of electrical behavior that semiconductors can exhibit, and extrinsic semiconductors are used to make semiconductor electronic devices such as diodes, transistors, integrated circuits, semiconductor lasers, LEDs, and photovoltaic cells.

The main difference between intrinsic and extrinsic semiconductor is that intrinsic semiconductors are pure in form, no form of impurity is added to them while extrinsic semiconductors being impure, contains the doping of trivalent or pentavalent impurities.

There are two types of extrinsic semiconductors: p-type (p for positive: a hole has been added through doping with a group-III element) and n-type (n for negative: an extra electron has been added through doping with a group-V element).

The semiconductor is divided into two types. The pure form of the semiconductor is known as the intrinsic semiconductor and the semiconductor in which intentionally impurities is added for making it conductive is known as the extrinsic semiconductor.

Intrinsic motivation comes from within, while extrinsic motivation arises from external factors. When you are intrinsically motivated, you engage in an activity because you enjoy it and get personal satisfaction from doing it. When you are extrinsically motivated, you do something in order to gain an external reward.

Difference Between Extrinsic and Intrinsic Semiconductors

Intrinsic semiconductors – definition An intrinsic semiconductor is a semiconductor in which no other material is intentionally doped (similar to mixing). Example: Si, Ge. The conductivity of intrinsic semiconductor is more than that of a pure semiconductor as the impurities provide a few energy levels in the bandgap.

Two main types of semiconductors are n-type and p-type semiconductors. (i) n-type semiconductors. Silicon and germanium (Group 14) have very low electrical conductivity in the pure state.

Holes and electrons are equal in number. Intrinsic semiconductors are called ‘undoped or i-type semiconductors. ‘ It is of two types, viz: n-type and p-type.

The symbols p and n come from the sign of the charge of the particles: positive for holes and negative for electrons.