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Related papers: Geometrical-confinement effects on excitons in qua…

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We investigate polarization properties of neutral exciton emission in single self-assembled InAs/GaAs quantum dots. The in-plane shape and strain anisotropy strongly couple the heavy and light hole states and lead to large optical…

Mesoscale and Nanoscale Physics · Physics 2013-04-18 C. Tonin , R. Hostein , V. Voliotis , R. Grousson , A. Lemaitre , A. Martinez

In this work, the effect of size and wetting layer on subband electronic envelop functions, eigenenergies, linear and nonlinear absorption coefficients and refractive indices of a dome-shaped InAs/GaAs quantum dot were investigated. In our…

Optics · Physics 2013-06-28 Mohammad Sabaeian , Ali Khaledi-Nasab

The demonstration of degeneracy of the exciton spin states is an important step towards the production of entangled photons pairs from the biexciton cascade. We measure the fine structure of exciton and biexciton states for a large number…

Making use of droplet epitaxy, we systematically controlled the height of self-assembled GaAs quantum dots by more than one order of magnitude. The photoluminescence spectra of single quantum dots revealed the strong dependence of the…

Mesoscale and Nanoscale Physics · Physics 2015-08-12 N. Ha , T. Mano , Y. L. Chou , Y. N. Wu , S. J. Cheng , J. Bocquel , P. M. Koenraad , A. Ohtake , Y. Sakuma , K. Sakoda , T. Kuroda

External control over the electron and hole wavefunctions geometry and topology is investigated in a p-i-n diode embedding a dot-in-a-well InAs/GaAsSb quantum structure with type II band alignment. We find highly tunable exciton dipole…

Due to the advantage of tunability via size, shape, doping and relatively low level of loss and high extent of spatial confinement, graphene quantum dots (GQDs) are emerging as an effective way to control light by molecular engineering. The…

Materials Science · Physics 2015-02-13 Sharma S. R. K. C Yamijala , Madhuri Mukhopadhyay , Swapan K. Pati

Wave functions of heavy-hole excitons in GaAs/Al$_{0.3}$Ga$_{0.7}$As square quantum wells (QWs) of various widths are calculated by the direct numerical solution of a three-dimensional Schr\"odinger equation using a finite-difference…

Mesoscale and Nanoscale Physics · Physics 2021-11-24 B. F. Gribakin , E. S. Khramtsov , A. V. Trifonov , I. V. Ignatiev

We present a theoretical analysis of the effect of dielectric confinement on the Coulomb interaction in dielectrically modulated quantum structures. We discuss the implications of the strong enhancement of the electron-hole and…

Materials Science · Physics 2009-10-31 G. Goldoni , F. Rossi , A. Orlandi , M. Rontani , F. Manghi , E. Molinari

Using three-dimensional k.p calculation including strain and piezoelectricity, we showed that the size of the quantum dot (QD) in the growth direction determines the influence of the (In,Ga)As capping layer on the optical properties of…

Materials Science · Physics 2009-11-13 V. Mlinar , F. M. Peeters

We study the symmetry classes of graphene quantum dots, both open and closed, through the conductance and energy level statistics. For abrupt termination of the lattice, these properties are well described by the standard orthogonal and…

Mesoscale and Nanoscale Physics · Physics 2009-02-09 J. Wurm , A. Rycerz , I. Adagideli , M. Wimmer , K. Richter , H. U. Baranger

Spatially structured light fields applied to semiconductor quantum dots yield fundamentally different absorption spectra than homogeneous beams. In this paper, we theoretically discuss the resulting spectra for different light beams using a…

Mesoscale and Nanoscale Physics · Physics 2020-11-04 M. Holtkemper , G. F. Quinteiro , D. E. Reiter , T. Kuhn

We present results of correlated pseudopotential calculations of an exciton in a pair of vertically stacked InGaAs/GaAs dots. Competing effects of strain, geometry, and band mixing lead to many unexpected features missing in contemporary…

Materials Science · Physics 2012-03-08 Gabriel Bester , J. Shumway , Alex Zunger

We report on a combined photoluminescence imaging and atomic force microscopy study of single, isolated self-assembled InAs quantum dots (density <0.01 um^(-2) capped by a 95 nm GaAs layer, and emitting around 950 nm. By combining optical…

Mesoscale and Nanoscale Physics · Physics 2017-07-27 Luca Sapienza , Jin Liu , Jin Dong Song , Stefan Falt , Werner Wegscheider , Antonio Badolato , Kartik Srinivasan

Excitons drive the optoelectronic properties of organic semiconductors which underpin devices including solar cells and light-emitting diodes. Here we show that excitons can exhibit topologically non-trivial states protected by inversion…

Mesoscale and Nanoscale Physics · Physics 2025-05-21 Wojciech J. Jankowski , Joshua J. P. Thompson , Bartomeu Monserrat , Robert-Jan Slager

In this review we discuss several fundamental processes taking place in semiconductor nanocrystals (quantum dots, QDs) when their electron subsystem interacts with electromagnetic (EM) radiation. The physical phenomena of light emission and…

Mesoscale and Nanoscale Physics · Physics 2021-01-12 Vladimir A. Burdov , Mikhail I. Vasilevskiy

The radiative recombination rates of interacting electron-hole pairs in a quantum dot are strongly affected by quantum correlations among electrons and holes in the dot. Recent measurements of the biexciton recombination rate in single…

Mesoscale and Nanoscale Physics · Physics 2008-06-17 Michael Wimmer , S. V. Nair , J. Shumway

Hole spin relaxation time due to the hole-acoustic phonon scattering in GaAs quantum dots confined in quantum wells along (001) and (111) directions is studied after the exact diagonalization of Luttinger Hamiltonian. Different effects such…

Materials Science · Physics 2007-05-23 C. Lü , J. L. Cheng , M. W. Wu

In this paper, a new mesoscopic polygon which possesses smooth transition at its corners is proposed. Because of the particularity of structure, this kind of mesoscopic polygon can also be a geometrical supperlattice. The geometrical…

Mesoscale and Nanoscale Physics · Physics 2009-03-03 Shengli Zhang , Qi Wang , Erhu Zhang

The structure of the ground state exciton of Cd(Se,Te) quantum dots embedded in ZnTe matrix is studied experimentally using photoluminescence spectroscopy and theoretically using ${\bf k}\cdot{\bf p}$ and configuration interaction methods.…

Mesoscale and Nanoscale Physics · Physics 2022-05-04 Petr Klenovský , Piotr Baranowski , Piotr Wojnar

We theoretically investigate the effects of long-range disorder and electron-electron interactions on the optical properties of hexagonal armchair graphene quantum dots consisting of up to 10806 atoms. The numerical calculations are…

Mesoscale and Nanoscale Physics · Physics 2017-02-08 A. Altıntaş , K. E. Çakmak , A. D. Güçlü