Lecture

Semiconductors and Charge Carriers

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Description

This lecture covers the basics of semiconductor physics, including materials, charge density, energy levels, electrons, holes, intrinsic and extrinsic semiconductors, doping, charge transport, diffusion current, and conductivity. It also discusses the mobility of electrons and holes, electrical conductivity, examples involving silicon doping, and current diffusion in semiconductors.

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Solid-state physics

Related concepts (32)

Doping (semiconductor)

In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties. The doped material is referred to as an extrinsic semiconductor. Small numbers of dopant atoms can change the ability of a semiconductor to conduct electricity. When on the order of one dopant atom is added per 100 million atoms, the doping is said to be low or light.

Semiconductor

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. 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.

Semiconductor device

A semiconductor device is an electronic component that relies on the electronic properties of a semiconductor material (primarily silicon, germanium, and gallium arsenide, as well as organic semiconductors) for its function. Its conductivity lies between conductors and insulators. Semiconductor devices have replaced vacuum tubes in most applications. They conduct electric current in the solid state, rather than as free electrons across a vacuum (typically liberated by thermionic emission) or as free electrons and ions through an ionized gas.

Magnetic semiconductor

Magnetic semiconductors are semiconductor materials that exhibit both ferromagnetism (or a similar response) and useful semiconductor properties. If implemented in devices, these materials could provide a new type of control of conduction. Whereas traditional electronics are based on control of charge carriers (n- or p-type), practical magnetic semiconductors would also allow control of quantum spin state (up or down).

Charge carrier

In physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. The term is used most commonly in solid state physics. In a conducting medium, an electric field can exert force on these free particles, causing a net motion of the particles through the medium; this is what constitutes an electric current.

Related lectures (64)

Understanding Semiconductor Behavior: Charge and Conductivity

Covers semiconductor behavior, focusing on energy levels, charge distributions, and conductivity in N-P-N structures and metal-semiconductor interfaces.

Semiconductor Materials: Charges and Energy Levels

Covers the fundamentals of semiconductor materials, including crystal structure, energy levels, electrons, holes, charge density, and doping.

Strain and Heteroepitaxy

Explores the impact of strain on semiconductor band structures, epitaxy, critical thickness, and defect formation, emphasizing the role of Hooke's law and elasticity theory.

Intrinsic Semiconductors: Thermal Generation and Carrier Concentration

Covers intrinsic semiconductors, focusing on thermal generation and carrier concentration calculations.

Understanding Ohmic Contacts: Schottky and Avalanche Effects