Home  About us  Contact
 

Single Quantum Dot (single + quantum_dot)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Photon statistics of a single quantum dot in a microcavity

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 10 2010
Yumian Su
Abstract We introduce a theoretical model to describe the dynamics of an electrically pumped single quantum dot interacting with a microcavity. Within our framework, it is possible to study the full photon statistics of the quantum light emission for different pump rates and to include semiconductor specific Pauli- blocking effects in the polarization dynamics. In the single photon limit, we find that, compared to comparable atomic systems, two photon events are suppressed stronger by the carrier reservoir of the quantum dot. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Influence of piezoelectric fields on excitonic complexes in InGaN quantum dots

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2009
K. Sebald
Abstract We present an analysis of the optical properties of single InGaN quantum dots (QDs) grown by MOVPE. The samples were structured into mesas by focused-ion-beam etching and investigated by micro-photoluminescence measurements. The QDs are characterized by the high temperature stability of their emission up to 150 K. Furthermore, the polarization of individual QD emission lines was analyzed giving an insight into their geometrical shape. Time-resolved microphotoluminescence measurements on the excitonic and biexcitonic transition of a single quantum dot yields a radiative recombination lifetime of 2.06 ns for the exciton. The data can be fitted by a simple model for cascaded emission confirming the expected refilling of the excitonic state by biexcitonic recombination. In addition, the influence of piezoelectric fields on the exciton and biexciton emission and on their binding energy in single QDs was investigated. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Single-particle state mixing and Coulomb localization in two-electron realistic coupled quantum dots

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007
Dmitriy V. Melnikov
Abstract The exchange coupling in a realistic double quantum dot system is computed as a function of the gate confinement and magnetic field using a hybrid multiscale approach where the many-body Schrödinger equation is solved exactly within the full quantum dot device environment. It is found that at zero magnetic field the exchange energy varies from meV to sub-,eV value as the confinement gate biases (tunneling barrier) are changed and the system is driven from a single quantum dot to two coupled quantum dots. At the same time the magnetic field of the singlet-triplet transition is weakly affected by the changes and remains at about 1 T in the same range of the gate biases. The small values of the exchange coupling in this structure are attributed to the large inter-electron separation arising when the Coulomb repulsion dominates tunneling. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Origin of asymmetric splitting of a neutral exciton in a single semiconductor quantum dot

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2006
I. Suemune
Abstract It is well-recognized that exciton-state energy splitting makes it difficult to generate entangled photon pairs (EPP) from a single quantum dot (QD). It will be shown that the splitting of the exciton states originates from not only QD anisotropy but also ionization of residual impurities. This result shows that the growth of highly pure barrier layers will be necessary for the generation of EPP. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Modulation spectroscopy on a single self assembled quantum dot

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2007
S. Seidl
Abstract We present high resolution modulation spectroscopy on single quantum dots and discuss briefly the differences to other spectroscopy techniques. We use this technique to study the excitonic fine structure while charging the quantum dot and applying mechanical strain to it. We also show that the fine structure can be used as a polarization analyzer. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

CdSe quantum dot in a ZnSe nanowire as an efficient source of single photons

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2009
A. Tribu
Abstract We report on our development of fabrication of CdSe QD in ZnSe nanowire. We have been able to obtain high quality structures with very good optical properties. This has allowed us to measure photon emission from single quantum dots and to demonstrate photon antibunching. We show that this new type of II,VI quantum dot is very promising for high temperature operation. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Microcavity modified spontaneous emission of single quantum dots

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007
G. S. Solomon
Abstract We summarize our earlier research showing how the radiative properties of an individual InAs quantum dot exciton state can be altered by their spatial and spectral position with respect to a discrete semiconductor microcavity mode. The InAs quantum dot is formed epitaxially in GaAs, and the microcavity is processed from a one-wavelength distributed Bragg reflector planar microcavity of GaAs and AlAs to form a sub-micrometer diameter pillar. Two states are tuned through a discrete cavity mode through sample temperature changes and show a spontaneous emission enhancement of 4. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Entangled photon pairs from radiative cascades in semiconductor quantum dots

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 15 2006
N. Akopian
Abstract Entangled photon pairs are emitted from a biexciton decay cascade of single quantum dots when spectral filtering is applied. We show this by experimentally measuring the density matrix of the polarization state of the photon pair emitted from a continuously pumped quantum dot. The matrix clearly satisfies the Peres criterion for entanglement. By applying in addition a temporal window, the quantum dot becomes an entangled light source. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]