Exciton Energies (exciton + energy)

Distribution by Scientific Domains


Selected Abstracts


Hydrostatic-pressure effects on the correlated electron,hole transition energies in GaAs,Ga1,xAlxAs semiconductor quantum wells

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2006
N. Raigoza
Abstract The effects of hydrostatic pressure on the correlated e,h transition energies in single GaAs,Ga1,xAlxAs quantum wells are calculated via a variational procedure, in the framework of the effective-mass and non-degenerate parabolic-band approximations. The valence-band anisotropy is included in our theoretical model by using different hole masses in different spatial directions. Both heavy- and light-hole exciton energies are obtained, and correlated e,h transition energies are found in good agreement with available experimental measurements. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Optical properties of Ga1,xInxAs/GaAs(001) quantum well superlattices: Exciton and polariton dispersion curves

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2004
N. Tomassini
Abstract Wannier exciton wavefunctions and energies have been computed in superlattices of strained Ga1,xInxAs/GaAs(001) quantum wells (SLQWs) using Luttinger Hamiltonian and accurate variational envelope functions. Exciton dispersion curves of the SLQWs are then obtained by computing exciton energies for different K -points of the corresponding first Brillouin zone. Photon dispersion curves, due to the background dielectric constant modulation, and the polariton dispersion curves have been computed in the semiclassical self-consistent framework. The results are discussed for the case of exciton energies far from the photonic gaps. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Magnetic-field-induced switching of spin injectionin Zn1,xMnxTe/ZnTe double quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
S. Shirotori
Abstract Magnetic-field-induced switching of the spin configuration and the resultant spin injection direction have been studied in a Zn1,xMnxTe/ZnTe double quantum well. The up- and down-spin excitons are injected from the Zn1,xMnxTe layers to the ZnTe well in weak magnetic fields, where both exciton energies in the Zn1,xMnxTe layer are higher than those in the ZnTe. Above the level crossing field, the down-spin exciton energy in the Zn1,xMnxTe layers becomes lower due to the giant Zeeman effect. Therefore, the up- and down-spin excitons are spatially separated in each layer and the down-spin exciton in the ZnTe layer is injected to the Zn1,xMnxTe. It means that the direction of the excitonic spin injection can be switched by the external field. The injection time increases from 12 psec to 300 psec toward the level crossing field of 2.5 T, since the spin-polarized excitons in those layers are associated and can cause reverse spin injection processes. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Exciton dynamics in quantum nano-structures of II,VI diluted magnetic semiconductors fabricated by electron-beam lithography

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
A. Uetake
Abstract Exciton dynamics in quantum dots (QDs) of II,VI diluted magnetic semiconductors (DMSs) has been studied by using an electron-beam lithography technique. The peak energy of excitonic photoluminescence in the QDs shows blue shifts up to 3.5 meV toward the dot diameter of 20 nm, indicating a lateral confinement effect for the exciton. The time-dependent energy shift of the exciton due to the localization is small as 2.9 meV, which originates from the suppression of the exciton diffusion due to the finite dot structure. The coupled QDs composed of a DMS magnetic well (MW) and a non-magnetic well (NW) were sucessfully fabricated, where the exciton energy in the NW was designed to be lower than that in the MW. The spin-polarized excitons migrate from the MW to the NW in magnetic fields and the exciton spin injection is demonstrated in the coupled QDs. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Magnetic-field-induced switching of spin injectionin Zn1,xMnxTe/ZnTe double quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
S. Shirotori
Abstract Magnetic-field-induced switching of the spin configuration and the resultant spin injection direction have been studied in a Zn1,xMnxTe/ZnTe double quantum well. The up- and down-spin excitons are injected from the Zn1,xMnxTe layers to the ZnTe well in weak magnetic fields, where both exciton energies in the Zn1,xMnxTe layer are higher than those in the ZnTe. Above the level crossing field, the down-spin exciton energy in the Zn1,xMnxTe layers becomes lower due to the giant Zeeman effect. Therefore, the up- and down-spin excitons are spatially separated in each layer and the down-spin exciton in the ZnTe layer is injected to the Zn1,xMnxTe. It means that the direction of the excitonic spin injection can be switched by the external field. The injection time increases from 12 psec to 300 psec toward the level crossing field of 2.5 T, since the spin-polarized excitons in those layers are associated and can cause reverse spin injection processes. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]