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Single InAs/GaAs Quantum Dot (single + inas/gaas_quantum_dot)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Fock-Darwin spectrum of a single InAs/GaAs quantum dot

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2006
A. Babinski
Abstract Magnetospectroscopic study of a highly excited single InAs/GaAs quantum dot is reported. Optical emission from the s- and p-shells is identified and investigated in magnetic fields up to 20T. The zero-field splitting and the Zeeman orbital splitting of the p-shell-related emission lines in magnetic field are observed. The evolution of spectra in magnetic field resembles a classical Fock-Darwin energy diagram, although effects of the electron-electron interaction and asymmetry of localizing potential can be clearly observed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Shape-dependent properties of self-organized quantum dots: Few-particle states and exciton-phonon coupling

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
R. Heitz
Abstract The electronic and optical properties of self-organized InAs/GaAs quantum dots are investigated in view of the actual structural properties. Focussing on the shape we demonstrate theoretically a strong impact of the varying strain distribution on the electronic and, in particular, the exciton properites in such quantum dots. The inhomogeneous strain, typical for self-organized quantum dots, lowers the symmetry and increases the local charge density. Resonant Raman experiments on pyramidal InAs/GaAs quantum dots show an enhance exciton,LO-phonon coupling reflecting the strain-induced local charge density. Experiments on single InAs/GaAs quantum dots demonstrate an unexpected strong impact of the structural properties on few-particle complexes on the example of the biexciton complex. Anti-binding biexciton complexes are demonstrated. The apparent correlation of the biexciton binding energy and exciton transition energy, with a transition from binding to anti-binding at ,1.24 eV, is attributed to a decreasing exciton localization, resulting from the finite barrier height. The Coulomb interaction with delocalized states is negligible for the energy of the localized states. [source]

Photocurrent spectroscopy of single InAs/GaAs quantum dots

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2005
G. Fasching
Abstract In this work, we present a carrier escape study from InAs/GaAs self assembled QD's by the use of photocurrent measurements. As a function of the applied field, we detect a shift of the exciton ground state transition due to the quantum-confined Stark shift. ¿From the measured Stark shift S = 4:3 meV we deduce a exciton dipole moment of p = (4.3 ± 0.2) × 10,29 Cm. The tunneling time, which is directly related to the observed photocurrent linewidth due to , , ,/(2,), changes by a factor of five in the photocurrent regime. The measured linewidth dependency on the electric field is modelled by a simple 1D WKB approximation for the tunneling process, which shows that the energetic position of the wetting layer is important for the measured tunneling time out of the dot. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]