Publication

Formation time of negatively charged excitons in CdTe-based quantum wells

Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Victoria Ciulin
2002
Journal Articles

Abstract

The formation dynamics of charged excitons is studied in CdTe-based quantum wells by picosecond time-resolved photoluminescence. The formation time is obtained by an analysis of temporal behavior of photoluminescence signal after excitation in resonance with either neutral or charged exciton. It is shown that the formation time varies strongly when changing the electron concentration. We also demonstrate that the localization of neutral excitons has strong impact on the formation time of charged exciton and is over two times longer when exciting the low energy side of neutral exciton line.

Official source

https://infoscience.epfl.ch/entities/publication/651adc26-5314-4b28-bc52-95279c761666

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Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Victoria Ciulin
2002
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/651adc26-5314-4b28-bc52-95279c761666

About this result

Related concepts (31)

Exciton

An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force. It is an electrically neutral quasiparticle that exists in insulators, semiconductors and some liquids. The exciton is regarded as an elementary excitation of condensed matter that can transport energy without transporting net electric charge. An exciton can form when a material absorbs a photon of higher energy than its bandgap. This excites an electron from the valence band into the conduction band.

Photoluminescence

Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence the prefix photo-. Following excitation, various relaxation processes typically occur in which other photons are re-radiated.

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.

Related publications (15)

Formation time of negatively charged excitons in CdTe-based quantum wells

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