Energy transfer between semiconductor ...
Document type :
Compte-rendu et recension critique d'ouvrage
Title :
Energy transfer between semiconductor nanocrystals : validity of Förster's theory
Author(s) :
Allan, Guy [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Delerue, Christophe [Auteur]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Delerue, Christophe [Auteur]

Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN]
Journal title :
Physical Review B: Condensed Matter and Materials Physics (1998-2015)
Pages :
195311
Publisher :
American Physical Society
Publication date :
2007
ISSN :
1098-0121
HAL domain(s) :
Physique [physics]/Matière Condensée [cond-mat]
English abstract : [en]
We theoretically study the energy transfer between semiconductor nanocrystals and we calculate the rate of this process in the case of direct-gap (InAs) and indirect-gap (Si) semiconductors. The calculations are based on ...
Show more >We theoretically study the energy transfer between semiconductor nanocrystals and we calculate the rate of this process in the case of direct-gap (InAs) and indirect-gap (Si) semiconductors. The calculations are based on the tight-binding method that enables us to determine the transfer rate, including electronic structure effects, dielectric screening, and multipolar Coulomb interactions using a microscopic approach. In the case of direct-gap semiconductor nanocrystals, we show that the energy transfer arises only from dipole-dipole interactions in agreement with experimental observations. We obtain that the transfer rate is well described by Förster’s theory, and we provide an analytical expression in which the Förster rate is determined not only by the spectral overlap between the emission and absorption spectra of the nanocrystals but also by a factor that simulates the dielectric effects on the Coulomb interactions. In the case of Si nanocrystals, the situation is different because dipolar transitions are weak due to the indirect gap of Si. For this reason, we show that multipolar terms dominate when the distance between the nanocrystals is small and surface effects play an important role in the screening. We predict that the energy transfer between Si nanocrystals by a no-phonon process is possible only when the dots are almost in close contact.Show less >
Show more >We theoretically study the energy transfer between semiconductor nanocrystals and we calculate the rate of this process in the case of direct-gap (InAs) and indirect-gap (Si) semiconductors. The calculations are based on the tight-binding method that enables us to determine the transfer rate, including electronic structure effects, dielectric screening, and multipolar Coulomb interactions using a microscopic approach. In the case of direct-gap semiconductor nanocrystals, we show that the energy transfer arises only from dipole-dipole interactions in agreement with experimental observations. We obtain that the transfer rate is well described by Förster’s theory, and we provide an analytical expression in which the Förster rate is determined not only by the spectral overlap between the emission and absorption spectra of the nanocrystals but also by a factor that simulates the dielectric effects on the Coulomb interactions. In the case of Si nanocrystals, the situation is different because dipolar transitions are weak due to the indirect gap of Si. For this reason, we show that multipolar terms dominate when the distance between the nanocrystals is small and surface effects play an important role in the screening. We predict that the energy transfer between Si nanocrystals by a no-phonon process is possible only when the dots are almost in close contact.Show less >
Language :
Anglais
Popular science :
Non
Source :
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