p-n junction
A p-n junction in a semiconductor is formed by a pair of polarized electrons and holes that are displaced by a positive charge on one side. The positive charge pushes an electron while the negative charges on the opposite side repel the hole. The result is that the minority carrier flows stop parallel to the junction. This is why the p–n junction acts as an insulation. You can create a capacitance by using the fixed pair of polarized electrons in the n region.
The negative charge decreases when a positive charge has been displaced. This causes an electric field to form at the p-n junction. This causes electrons on the p side to drift toward the n side. This is the opposite of diffusion current, which flows in the opposite direction.
Energy gap
A property that can be measured in semiconductors is the energy gap or valence bands gap. This property relates the total energy of the semiconductor to the total energy of the electrons or holes. A single-crystal silicon is a semiconductor with an energy gap that is close to unity.
The refractive index of a semiconductor is a function of its energy gap, and is a vital consideration in the design of optoelectronic devices. This property is important for optically tunable diodes, but there are few data on the refractive index of various semiconductor groups.
Conductivity
The conductivity of semiconductors is directly related to the number of free carriers in the semiconductor. The material's electrical conductivity is determined by the number of carriers per unit volume, and their relative velocity in an electric field. An intrinsic semiconductor contains equal numbers of electrons and holes. These ions are at different velocities and therefore have different mobilities in an electric field.
The conduction band refers to the number or free electrons found in a semiconductor. At room temperatures, this electron/hole relationship means one electron moves into its conduction band and one electron to the valance bands. These electron-hole pairs are therefore considered charge carriers.
Characteristics
Semiconductors have different properties compared to metals, including their conductivity and their resistivity. They vary in the number of electrons or holes per unit area. Their conductivity drops with temperature, and they have a negative temperature coefficient of resistance. Their properties can be altered by semiconductor impurities which can impact their electrical conductivity.
These properties make them ideal for electronic devices. They are also the foundation of computers. Semiconductors can be described as solid chemical elements that conduct electricity when certain conditions are met. Because of this, they are the perfect medium for regulating electrical current. There are two types of semiconductors: conductor and insulator. Exposing a semiconductor to an electrical field causes its electrons or holes to move at a rapid rate.
Applications
Semiconductors are materials that have optical properties and are used in a variety of technologies. Semiconductors are a key component of many everyday technologies, including mobile phones and computers. This book explores the most important optical properties of these materials. The book includes contributions by experts who share their insights and expertise on the subject.
Semiconductors often are used to create transistors or MOSFETs which act as switches within electrical 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.