Publication

Radiative behavior of negatively charged excitons in CdTe-based quantum wells: A spectral and temporal analysis

Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Victoria Ciulin, Stefan Haacke
2000
Journal Articles

Abstract

Using reflectivity and picosecond time-resolved photoluminescence, we have studied the intrinsic optical properties of negatively charged excitons in modulation doped CdTe quantum wells. In emission, we observe simultaneously a low energy exponential tail in the charged exciton spectral line and a linear increase of its radiative lifetime with temperature. In absorption, we find a consistent decrease of the charged exciton oscillator strength with temperature. For low electron concentrations these observations are well reproduced by a model of delocalized and thermalized three-particle complexes. The model takes into account the recoil momentum of the electron during the charged exciton optical transition. It is further found to compare well with lifetime measurements up to high carrier concentrations. Small deviations from the theoretical predictions occur only below 7 K due to localization effects and for the highest carrier concentration of n(e)similar to2 x 10(11) cm(-2).

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https://infoscience.epfl.ch/entities/publication/edd3fe4d-5b42-4ff7-8374-8e2659a4a0cb

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Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Victoria Ciulin, Stefan Haacke
2000
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/edd3fe4d-5b42-4ff7-8374-8e2659a4a0cb

About this result

Related concepts (32)

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.

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, .

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.

Related publications (2)

Radiative behavior of negatively charged excitons in CdTe-based quantum wells: A spectral and temporal analysis

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