We report accurate measurements of the excitonic ground state transitions in individual, strain free, GaAs/Al0.3Ga0.7As quantum dots. We determine the spectral width and the energy of the zero-phonon line as a function of the temperature for a series of quantum dots with different sizes. In particular, the thermal broadening is well reproduced by a thermally activated process having a single activation energy (36 meV, corresponding to the GaAs LO phonon energy) independently of the dot size. Similarly, the energy of the zero-phonon line follows the GaAs gap temperature dependence irrespective of the dot size. Our findings demonstrate that (a) the exciton decoherence in quantum dots cannot be attributed to inelastic electron-phonon scattering but rather to pure dephasing processes driven by GaAs-LO phonons and (b) there is no quantum size effect on the excitonic energy renormalization with the temperature.

Sanguinetti, S., Poliani, E., Bonfanti, M., Guzzi, M., Grilli, E., Gurioli, M., et al. (2006). Electron-phonon interaction in individual strain-free GaAs Al0.3 Ga0.7 As quantum dots. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 73(12), 125342 [10.1103/PhysRevB.73.125342].

Electron-phonon interaction in individual strain-free GaAs Al0.3 Ga0.7 As quantum dots

SANGUINETTI, STEFANO;GUZZI, MARIO;GRILLI, EMANUELE ENRICO;
2006

Abstract

We report accurate measurements of the excitonic ground state transitions in individual, strain free, GaAs/Al0.3Ga0.7As quantum dots. We determine the spectral width and the energy of the zero-phonon line as a function of the temperature for a series of quantum dots with different sizes. In particular, the thermal broadening is well reproduced by a thermally activated process having a single activation energy (36 meV, corresponding to the GaAs LO phonon energy) independently of the dot size. Similarly, the energy of the zero-phonon line follows the GaAs gap temperature dependence irrespective of the dot size. Our findings demonstrate that (a) the exciton decoherence in quantum dots cannot be attributed to inelastic electron-phonon scattering but rather to pure dephasing processes driven by GaAs-LO phonons and (b) there is no quantum size effect on the excitonic energy renormalization with the temperature.
Articolo in rivista - Articolo scientifico
MODIFIED DROPLET EPITAXY; TEMPERATURE-DEPENDENCE; ENERGY-GAP; GAAS; DENSITY
English
mar-2006
73
12
125342
125342
none
Sanguinetti, S., Poliani, E., Bonfanti, M., Guzzi, M., Grilli, E., Gurioli, M., et al. (2006). Electron-phonon interaction in individual strain-free GaAs Al0.3 Ga0.7 As quantum dots. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 73(12), 125342 [10.1103/PhysRevB.73.125342].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/1684
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