Lecture

Semiconductors: Basic Properties

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.

In course

PHYS-310: Solid state physics II

Ce cours de deux semestres donne une introduction à la Physique du solide, à la structure cristalline, aux vibrations du réseau, aux propriétés électroniques, de transport thermique et électrique ainsi qu'aux propriétés magnétiques. Il se situe au niveau d ...

Description

This lecture covers the basic properties of semiconductors, including the increase in conductivity with temperature, the influence of impurities on properties, and the role of holes in conductivity. It also discusses the temperature dependence of semiconductors and metals, intrinsic behavior at high temperatures, band gap measurements through optical absorption, and direct vs. indirect band gaps. The lecture concludes with a focus on crystal structures of Si, Ge, and GaAs, as well as real band structures using Ge as an example.

Instructors (3)

Harald Brune

Originaire de Münich en Allemagne, né en 1961, Harald Brune obtient son diplôme en physique de l'Université Ludwig Maximilians en 1989. Après une thèse en chimie physique à l'Institut Fritz-Haber de la Société Max-Planck à Berlin il obtient son titre de docteur ès sciences en 1992. Dès cela, il rejoint le groupe du Prof. K. Kern à l'Institut de physique expérimentale à l'EPFL. En 1995 il est chercheur invité à Copenhague travaillant en modélisation chez le Prof. J. Nørskov. De retour à l'EPFL, il se voit décerné le prix Latsis EPFL 1996 pour ses études par microscopie à effet tunnel de processus atomiques déterminants la croissance cristalline de couches minces. En 1998 il obtient son habilitation (venia legendi) en Physique et est nommé Maître d'enseignement et de recherche (MER) en nanophysique à l'EPFL. La même année il recoit une offre de Professeur Ordinaire (C4) de l'Université Philipps de Marburg. Début 1999 il réfuse cette offre et accepte un poste de Professeur Extraordinaire à l'EPFL et s'installe au sein de l'Institut de la Physique des Nanostructures. Il est nommé Professeur Ordinaire en 2005. Sa recherche porte sur les propriétés physiques (en particulier le magnétisme et la structure électronique) de nouvelles formes de la matière condensée comme des nanostructures et des couches ultra-minces. Il s'intéresse également à la catalyse hétérogène sur des systèmes inspirés dans leur composition et taille par celle des sites actives dans les enzymes en biologie. Il enseigne la Physique Générale pour ingénieurs, la Physique des matériaux solides pour physiciens, les méthodes expérimentales pour physiciens, ainsi que la Physique des surfaces, interfaces et nanostrcutures à l'école doctorale.

Oleg Yazyev

Prof. Oleg Yazyev (Олег Язев) was born in Simferopol, Crimean peninsula. He obtained his degree in chemistry from Moscow State University in 2003. He then joined Ecole Polytechnique Fédérale de Lausanne (EPFL) completing his PhD thesis in chemistry and chemical engineering in 2007. Next two years he has spent as a postdoctoral fellow at the Institute of Theoretical Physics (ITP) and the Institute for Numerical Research in the Physics of Materials (IRRMA) of the same institution. In 2009-2011 he was a postdoctoral fellow at the Department of Physics of the University of California, Berkeley and the Lawrence Berkeley National Laboratory. In September 2011 he started an independent research group supported by the Swiss National Science Foundation professorship grant. In 2012 he was awarded an ERC Starting grant. His current research focuses on theoretical and computational physics of two-dimensional and topological materials with strong emphasis on their prospective technological applications. ResearcherID profile of Oleg Yazyev Google Scholar profile of Oleg Yazyev

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Solid-state physics

Related concepts (32)

Electronic band structure

In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energy levels that electrons may have within it, as well as the ranges of energy that they may not have (called band gaps or forbidden bands). Band theory derives these bands and band gaps by examining the allowed quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules.

Band gap

In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the energy difference (often expressed in electronvolts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band.

Band bending

In solid-state physics, band bending refers to the process in which the electronic band structure in a material curves up or down near a junction or interface. It does not involve any physical (spatial) bending. When the electrochemical potential of the free charge carriers around an interface of a semiconductor is dissimilar, charge carriers are transferred between the two materials until an equilibrium state is reached whereby the potential difference vanishes.

Valence and conduction bands

In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states. On a graph of the electronic band structure of a semiconducting material, the valence band is located below the Fermi level, while the conduction band is located above it.

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.

Related lectures (64)

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.

Density of States in Semiconductor Devices

Explores density of states in semiconductor devices, covering electron gas, energy bands, Fermi-Dirac distribution, and band structures.

Intrinsic Semiconductors: Thermal Generation and Carrier Concentration

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

Effective Masses in Semiconductor Physics

Covers effective masses in semiconductors, focusing on energy bands and their implications for materials like silicon and gallium arsenide.

Semiconductors: Band Structure and Carrier Concentration