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Lecture

Light-Emitting Diodes: Efficiency and Applications

In course

PHYS-434: Physics of photonic semiconductor devices

Series of lectures covering the physics of quantum heterostructures, dielectric microcavities and photonic crystal cavities as well as the properties of the main light emitting devices that are light-emitting diodes (LEDs) and laser diodes (LDs). ...

Description

This lecture delves into the applications and markets of light-emitting diodes (LEDs), covering carrier injection and recombination processes, spectral distribution, and internal quantum efficiency. It explores LED structures, semiconductor materials, and key markets such as automotive, consumer electronics, and general lighting. The lecture also discusses emerging trends in 3D sensing, LED chip technology, and the future scope of LED applications.

Instructors (2)

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

Electrical engineering

Photonics: Topics in photonics

Related concepts (32)

Lighting

Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings.

Light-emitting diode

A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

Stage lighting

Stage lighting is the craft of lighting as it applies to the production of theater, dance, opera, and other performance arts. Several different types of stage lighting instruments are used in this discipline. In addition to basic lighting, modern stage lighting can also include special effects, such as lasers and fog machines. People who work on stage lighting are commonly referred to as lighting technicians or lighting designers. The equipment used for stage lighting (e.g.

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 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.

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Physics of Photonic Semiconductor Devices

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Physics of Photonic Semiconductor Devices: LEDs and Laser Diodes

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Efficiency of LEDs: Fabrication and Comparison

Explores LED efficiency, fabrication, and comparison with alternative light sources, emphasizing the importance of the color rendering index.

Nanostructured Devices: Low Dimensional Materials and Applications

Explores low-dimensional devices, focusing on nanowires and quantum dots, their properties, applications, and the challenges in their fabrication and performance.

Semiconductor Physics: Fundamentals and Applications