Lecture

Semiconductor Physics: Occupancy Statistics and Band Filling

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In course

PHYS-433: Semiconductor physics and light-matter interaction

Lectures on the fundamental aspects of semiconductor physics and the main properties of the p-n junction that is at the heart of devices like LEDs & laser diodes. The last part deals with light-matter interaction phenomena in bulk semiconductors such as ab ...

Description

This lecture delves into the concepts of occupancy statistics and band filling in semiconductors, covering intrinsic and doped cases, including degenerate and non-degenerate scenarios. It explores the neutrality condition, tracking the evolution of free carrier concentration with temperature. The impact of a moderate electric field on free carrier transport properties is also discussed, emphasizing the Maxwell-Boltzmann distribution and the concept of mobility from the Drude model.

Instructor

Raphaël Butté

Raphaël Butté was born in Paris, France, in 1973. He received the PhD degree from the University Claude Bernard, Lyon, France, in 2000 for his research on the structural and optoelectronic properties of hydrogenated nanostructured silicon thin films with potential applications for photovoltaics and thin film transistors. He then moved to the University of Sheffield (2000-2003), UK, to work as postdoctoral research associate in the group of Prof. Maurice S. Skolnick (Fellow of the Royal Society). His research shifted to the optical properties of III-V semiconductors with a main focus on the nonlinear optical properties of cavity polaritons occurring in GaAs-based microcavities driven under resonant optical excitation. In 2004, he moved to Ecole Polytechnique Fédérale de Lausanne (EPFL) as scientific collaborator in charge of optical spectroscopy at LASPE (http://laspe.epfl.ch/), a newly established laboratory directed by Prof. Nicolas Grandjean. In 2010, he became permanent member of staff (Scientific Collaborator and Lecturer). He was promoted to the position of Senior Scientist in 2016. His current research activity deals with planar waveguides, microdisks and photonic crystals made from III-nitride semiconductors. In particular, he is leading the activity focusing on: (i) the physics of exciton-polaritons in planar waveguides and (ii) high-β photonic crystal nanolasers. He is the author of 119 scientific articles published in peer-reviewed international journals, 14 publications published in peer reviewed journals following an international conference (Web of Science > 4500 citations, h-index: 36; Google Scholar > 6200 citations, h-index: 42) and 6 book chapters. He has given 30 invited talks in International Conferences/Winter-Summer Schools/Workshops. He has been the Publications Chair/Guest Editor of the Proceedings of the 5th International Workshop on Nitride semiconductors (IWN2008) and also served as Scientific Secretary of IWN2008 and of the 5th International Conference on Spontaneous Coherence in Excitonic Systems (ICSCE5). In 2012, he was one of the 149 scientists recognized by the Outstanding Referee program (http://publish.aps.org/OutstandingReferees) of the American Physical Society (APS) selected from a pool of roughly 60,000 currently active referees. Since September 2019, he is an Editorial Board Member of the newly launched open access APS journal, Physical Review Research. From September 2013 until December 2017, he was one of the Editors of the journal "Superlattices and Microstructures" (Elsevier). Since September 2015 he is a member of the Physics Doctoral School Teaching Committee. He was also a member of the EPFL Teaching Conference from September 2015 until August 2017.

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Solid-state physics

Related concepts (32)

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.

Electron mobility

In solid-state physics, the electron mobility characterises how quickly an electron can move through a metal or semiconductor when pulled by an electric field. There is an analogous quantity for holes, called hole mobility. The term carrier mobility refers in general to both electron and hole mobility. Electron and hole mobility are special cases of electrical mobility of charged particles in a fluid under an applied electric field. When an electric field E is applied across a piece of material, the electrons respond by moving with an average velocity called the drift velocity, .

Maxwell–Boltzmann distribution

In physics (in particular in statistical mechanics), the Maxwell–Boltzmann distribution, or Maxwell(ian) distribution, is a particular probability distribution named after James Clerk Maxwell and Ludwig Boltzmann. It was first defined and used for describing particle speeds in idealized gases, where the particles move freely inside a stationary container without interacting with one another, except for very brief collisions in which they exchange energy and momentum with each other or with their thermal environment.

Boltzmann distribution

In statistical mechanics and mathematics, a Boltzmann distribution (also called Gibbs distribution) is a probability distribution or probability measure that gives the probability that a system will be in a certain state as a function of that state's energy and the temperature of the system. The distribution is expressed in the form: where pi is the probability of the system being in state i, exp is the exponential function, εi is the energy of that state, and a constant kT of the distribution is the product of the Boltzmann constant k and thermodynamic temperature T.

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