"A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass."
Concerns with the study of semiconductors, materials that have properties that lie between those of conductors and insulators.
Crystal structure: The arrangement of atoms in a crystal lattice affects the electronic and mechanical properties of a semiconductor.
Band theory: Describes the electronic structure of solids in terms of valence and conduction bands.
Carrier concentration: The number of free electrons or holes in a semiconductor material, which determines its electrical conductivity.
Doping: The intentional addition of impurities to a semiconductor material to alter its electrical properties and create p-type and n-type semiconductors.
PN junction: The interface between a p-type and n-type material, which enables the creation of diodes and transistors.
Schottky diode: A metal-semiconductor contact, which behaves like a diode due to the built-in potential.
MOS capacitor: A metal-oxide-semiconductor structure that can be used as a capacitance or as the dielectric in a MOSFET.
MOSFET: A metal-oxide-semiconductor field-effect transistor, which can be used as a switch or amplifier in electronic circuits.
Heterojunction: The interface between two different semiconductor materials, which can be used to create high-performance devices such as LEDs and solar cells.
Quantum wells: A thin layer of semiconductor material with a lower bandgap than the surrounding material, which is used to confine electrons and produce quantum-confined Stark effect.
Quantum dots: Ultra-small semiconducting materials that exhibit quantum confinement effects and have potential applications in optoelectronics and quantum computing.
Tunnelling: The transfer of electrons or holes through a potential barrier, which is used in tunnel diodes and quantum computing.
Spintronics: The study of the spin of electrons in semiconductors, which could lead to new technologies such as spin transistors and magnetic memory devices.
2D materials: The study of single or few-layer materials such as graphene and transition metal dichalcogenides, which have unique electronic and optical properties.
Plasmonics: The study of the interaction between electromagnetic waves and free electrons in metal and semiconductor materials, which can be used in applications such as sensing and data storage.
Band theory: This is the study of the electronic band structure in solids, which helps to explain many of the electrical and optical properties of semiconductors.
Carrier dynamics: This is the study of how charged particles (carriers) move and interact within a semiconductor, and how this affects its electrical properties.
Quantum transport: This is the study of how electrons move through a semiconductor under the influence of quantum mechanics, which can be used to design new types of electronic devices.
Surface and interface physics: This is the study of the electronic and structural properties of semiconductor surfaces and interfaces, which are important for understanding how devices interact with their environment.
Semiconductor defects: This is the study of impurities and defects in semiconductors, which can dramatically affect their electrical and optical properties.
Semiconductor device physics: This is the study of the physics behind semiconductor devices, including transistors, diodes, and solar cells.
Nanostructures: This is the study of semiconductor materials and devices on the nanoscale, which can have unique electronic properties that are not found in larger structures.
Optoelectronics: This is the study of the interaction between light and semiconductors, which is important for developing new types of lasers, detectors, and displays.
Semiconductor spectroscopy: This is the study of the electronic and optical properties of semiconductors, which can be probed using a variety of spectroscopic techniques.
Semiconductor materials: This is the study of the physical and chemical properties of materials that are used to make semiconductors, including silicon, gallium arsenide, and organic materials.
"Its resistivity falls as its temperature rises; metals behave in the opposite way."
"Its conducting properties may be altered in useful ways by introducing impurities ('doping') into the crystal structure."
"When two differently doped regions exist in the same crystal, a semiconductor junction is created."
"The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics."
"Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called 'metalloid staircase' on the periodic table."
"After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others."
"Because the electrical properties of a semiconductor material can be modified by doping and by the application of electrical fields or light, devices made from semiconductors can be used for amplification, switching, and energy conversion."
"The conductivity of silicon is increased by adding a small amount (of the order of 1 in 10^8) of pentavalent (antimony, phosphorus, or arsenic) or trivalent (boron, gallium, indium) atoms."
"This process is known as doping, and the resulting semiconductors are known as doped or extrinsic semiconductors."
"Apart from doping, the conductivity of a semiconductor can be improved by increasing its temperature. This is contrary to the behavior of a metal, in which conductivity decreases with an increase in temperature."
"The modern understanding of the properties of a semiconductor relies on quantum physics to explain the movement of charge carriers in a crystal lattice."
"When a doped semiconductor contains free holes, it is called 'p-type', and when it contains free electrons, it is known as 'n-type'."
"The semiconductor materials used in electronic devices are doped under precise conditions to control the concentration and regions of p- and n-type dopants."
"Using a hot-point probe, one can determine quickly whether a semiconductor sample is p- or n-type."
"The first practical application of semiconductors in electronics was the 1904 development of the cat's-whisker detector, a primitive semiconductor diode used in early radio receivers."
"Developments in quantum physics led in turn to the invention of the transistor in 1947."
"The integrated circuit was invented in 1958."
"Semiconductor devices can display a range of different useful properties, such as passing current more easily in one direction than the other, showing variable resistance, and having sensitivity to light or heat."
"Devices made from semiconductors can be used for amplification, switching, and energy conversion."