p-n junction
A pair of polarized holes and electrons create a p-n junction within a semiconductor. The positive charge on the other side displaces the hole. The negative charge on the other side repels the hole, while the positive charge pushes the electron. The result is that the minority carrier flows stop parallel to the junction. As a result, the p-n junction acts as an insulator. The n-region contains a fixed pair electrons polarized so it can be used for creating a capacitance.
A positive charge can be displaced to reduce the negative charge, which causes an electric field along the p–n junction. This causes electrons on the p side to drift toward the n side. This is the opposite to diffusion current, which flows the opposite way.
Energy gap
An energy gap, or valence band gap, is a property that can be measured in semiconductors. This property refers to the total amount of energy in the semiconductor relative to the total energies of the electrons and holes. A single crystal semiconductor is one with an energy difference close to unity.
The refractive index is a function the semiconductor's energy gap. It is an important consideration when designing optoelectronic device. This property is important for optically tunable diodes, but there are few data on the refractive index of various semiconductor groups.
Conductivity
Conductivity of semiconductors directly depends on the number of free carriers within the semiconductor. The electrical conductivity of a material is determined by its number of carriers per volume and relative velocities under an electric field. An intrinsic semiconductor has the same number of electrons as holes. These ions have different speeds and so are able to move in different electric fields.
Its conduction spectrum is the number and type of free electrons within a semiconductor. At room temperatures, this electron/hole relationship means one electron moves into its conduction band and one electron to the valance bands. This is why these electron-hole pair are charged carriers.
Characteristics
Semiconductors possess different properties than metals. These include their conductivity, and resistivity. They differ in how many electrons and holes they have per area. Their temperature coefficient of resistivity is negative and their conductivity declines with increasing temperature. Impurities in semiconductors can also alter their properties, which may affect their electrical conductivity.
These properties make it ideal for electronic device, and they form the basis for computers. Semiconductors, which are usually solid chemical elements, conduct electricity under certain conditions. They are therefore ideal for controlling electric current. There are two types if semiconductors: the conductor and the insulator. If a semiconductor is exposed in an electric field, electrons and holes are able to move at high speeds.
Applications
Semiconductors, which are materials with optical properties, are used in many technologies. They are integral components of daily-use technologies such as computers and mobile phones, and are being increasingly incorporated into everyday devices. This book explores the most important optical properties of these materials. The book features contributions from experts and insight on the subject.
Semiconductors can be used to make transistors and MOSFETs that act as switches in circuits. These materials are efficient and small, making them a good choice to use in many electronic applications. They can also make microprocessors or LEDs.