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Exciton Localization (exciton + localization)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Exciton localization in MgxZnyCd1,x,ySe alloy

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2004
O. Maksimov
Abstract We report photoluminescence and reflectivity measurements of MgxZnyCd1,x,ySe epitaxial layers (0 < x < 0.53) grown by molecular beam epitaxy on InP (100) substrates. Significant emission line broadening, increase in activation energy and Stokes shift are monitored with increasing Mg content. For MgxCdyZn1,x,ySe samples with large Mg content (x > 0.3), we observe an anomalous temperature dependence of both the emission energy and line broadening. This behavior is assigned to the emission from localized states. Different mechanisms of carrier localization are discussed and exciton localization on statistical CdSe clusters is proposed to be the most likely one. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Exciton localization in Al-rich AlGaN ternary alloy epitaxial layers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010
Hideaki Murotani
Abstract Exciton localization in Al-rich AlGaN ternary alloy epitaxial layers has been studied by means of temperature-dependent photoluminescence (PL) spectroscopy. Anomalous temperature dependence of the PL peak energy (red-blue shift) was observed, which enabled us to estimate the localization energy of excitons. The localization energy increased as the 1.2th power of the exciton linewidth. The value of exponent for Al-rich alloys was smaller than that for Ga-rich alloys. This indicated that the excitons in Al-rich alloys were strongly localized compared to that in Ga-rich alloys. In addition, the exponent value for Al-rich alloys increased with increasing excitation power density. This increase in the exponent suggested that the exciton population approached the extended states owing to the saturation of localized states by photo-generated excess excitons. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Strong coupling in artificial semimagnetic Cd(Mn,Mg)Te quantum dot molecule

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 15 2006
S. V. Zaitsev
Abstract Exciton photoluminescence in a pair of strongly coupled artificial asymmetric quantum dots (QDs) has been studied in a magnetic field up to 8 T. The QD molecules have been fabricated by a selective interdiffusion technique applied to asymmetric semimagnetic CdTe/Cd(Mg,Mn)Te double quantum wells. The lateral confinement potential within the plane, induced by the diffusion, gives rise to effective zero-dimensional exciton localization. In contrast to a typically positive exciton Lande g -factor, an exciton transition in the non-magnetic QD demonstrates a nearly zero g -factor, indicating a strong electron tunnel coupling between the QDs. The strong coupling results in the formation of an inter-QDs indirect exciton, which is a ground exciton state at high magnetic field, as found in the experiment and confirmed by our calculations. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Exciton localization in MgxZnyCd1,x,ySe alloy

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2004
O. Maksimov
Abstract We report photoluminescence and reflectivity measurements of MgxZnyCd1,x,ySe epitaxial layers (0 < x < 0.53) grown by molecular beam epitaxy on InP (100) substrates. Significant emission line broadening, increase in activation energy and Stokes shift are monitored with increasing Mg content. For MgxCdyZn1,x,ySe samples with large Mg content (x > 0.3), we observe an anomalous temperature dependence of both the emission energy and line broadening. This behavior is assigned to the emission from localized states. Different mechanisms of carrier localization are discussed and exciton localization on statistical CdSe clusters is proposed to be the most likely one. (© 2004 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]