Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Surface Energy and Semiconductor Nanostructures

Description

This lecture covers the surface energy of various materials like C, Si, and Ge, the equilibrium crystal shape of Si, and the anisotropy of surface energy for Si. It also discusses the reconstruction of semiconductor surfaces, band schemes of n-doped semiconductors, and the role of surfaces in determining the electrical properties of semiconductors. The lecture further explores the deactivation of donors in silicon nanostructures and the impact of dopants in nanostructures compared to bulk materials.

Official source

Related concepts (23)

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.

Ion

An ion (ˈaɪ.ɒn,_-ən) is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons.

Dopant

A dopant (also called a doping agent) is a trace of impurity element that is introduced into a chemical material to alter its original electrical or optical properties. The amount of dopant necessary to cause changes is typically very low. When doped into crystalline substances, the dopant's atoms get incorporated into its crystal lattice. The crystalline materials are frequently either crystals of a semiconductor such as silicon and germanium for use in solid-state electronics, or transparent crystals for use in the production of various laser types; however, in some cases of the latter, noncrystalline substances such as glass can also be doped with impurities.

Related lectures (33)

Surface Properties: Understanding Semiconductors and Nanomaterials

Covers the significance of surface properties in semiconductors and nanomaterials, including surface energy, reconstruction, and the effects of surface states on electronic behavior.

Semiconductor Physics: Donors and Acceptors

Covers the role of donors and acceptors in semiconductor physics and the control of conductivities.

Doping in Semiconductors: Carrier Concentration and Ionization Energy

Discusses doping in semiconductors, focusing on carrier concentration, ionization energy, and the effects of temperature on electrical properties.

Band and Band-like Transport

Explores band and band-like transport in materials, including criteria, examples, charge transfer, and second quantization.

Electrical Conductivity of Metals: Semiconductor Properties

Explores electrical conductivity of metals, semiconductor properties, and energy bands.

Related concepts (23)

Doping (semiconductor)