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Recent experimental measurements, without any theoretical guidance, showed that isotropic polarization response can be achieved by increasing the number of QD layers in a QD stack. Here we analyse the polarization response of multi-layer…

Materials Science · Physics 2011-09-26 Muhammad Usman , Tomoya Inoue , Yukihiro Harda , Gerhard Klimeck , Takashi Kita

Tailoring electronic and optical properties of self-assembled InAs quantum dots (QDs) is a critical limit for the design of several QD-based optoelectronic devices operating in the telecom frequency range. We describe how a fine control of…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Vittorianna Tasco , Muhammad Usman , Milena De Giorgi , Adriana Passaseo

The design of some optical devices such as semiconductor optical amplifiers for telecommunication applications requires polarization-insensitive optical emission at the long wavelengths (1300-1550 nm). Self-assembled InAs/GaAs quantum dots…

Materials Science · Physics 2015-05-20 Muhammad Usman , Susannah Heck , Edmund Clarke , Peter Spencer , Hoon Ryu , Ray Murray , Gerhard Klimeck

This work presents an analysis of the electronic and optical properties of InAs/GaAs columnar quantum dots (QDs) by performing multi-million-atom tight-binding simulations. The plots of the polarisation-dependent ground state optical…

Mesoscale and Nanoscale Physics · Physics 2020-06-30 Muhammad Usman

The authors report that anisotropic confining potentials in laterally-coupled semiconductor quantum dots (QDs) have large impacts in optical transitions and energies of inter-shell collective electronic excitations. The observed…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Achintya Singha , Vittorio Pellegrini , Sokratis Kalliakos , Biswajit Karmakar , Aron Pinczuk , Loren N. Pfeiffer , Ken W. West

III-V growth and surface conditions strongly influence the physical structure and resulting optical properties of self-assembled quantum dots (QDs). Beyond the design of a desired active optical wavelength, the polarization response of QDs…

The demonstration of isotropic polarization response from semiconductor quantum dots (QDs) is a crucial step towards the design of several optoelectronic technologies. Among many parameters that impact the degree of polarization (DOP) of a…

Mesoscale and Nanoscale Physics · Physics 2012-10-09 Muhammad Usman

We study the polarization response of the emission from type-II GaAsSb capped InAs quantum dots. The theoretical prediction based on the calculations of the overlap integrals of the single-particle states obtained in the k.p framework is…

Mesoscale and Nanoscale Physics · Physics 2016-12-13 P. Klenovsky , D. Hemzal , P. Steindl , M. Zikova , V. Krapek , J. Humlicek

We report electrical control of the spin polarization of InAs/GaAs self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular…

We derive a general relation between the fine structure splitting (FSS) and the exciton polarization angle of self-assembled quantum dots (QDs) under uniaxial stress. We show that the FSS lower bound under external stress can be predicted…

Materials Science · Physics 2015-05-20 Ming Gong , Weiwei Zhang , Guang-Can Guo , Lixin He

Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively…

Mesoscale and Nanoscale Physics · Physics 2013-08-01 Muhammad Usman , Yui-Hong Matthias Tan , Hoon Ryu , Shaikh S. Ahmed , Hubert Krenner , Timothy B. Boykin , Gerhard Klimeck

We introduce a method which enables to directly compare the impact of elastic strain on the optical properties of distinct quantum dots (QDs). Specifically, the QDs are integrated in a cross-section of a semiconductor core wire which is…

We report on stacked multiple quantum dots (QDs) formed inside inverted pyramidal recesses, which allow for the precise positioning of the QDs themselves. Specifically we fabricated double QDs with varying inter-dot distance and ensembles…

Mesoscale and Nanoscale Physics · Physics 2017-09-01 S. T. Moroni , T. H. Chung , G. Juska , A. Gocalinska , E. Pelucchi

The optical properties of excitons confined in initially-unstrained GaAs/AlGaAs quantum dots are studied as a function of a variable quasi-uniaxial stress. To allow the validation of state-of-the-art computational tools for describing the…

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

We present a comprehensive investigation of the polarization properties of non-polar a-plane InGaN quantum dots (QDs) and their origin with statistically significant experimental data and rigorous k.p modelling. The unbiased selection and…

We use an $sp^3d^5s^* $ tight-binding model to investigate the electronic and optical properties of realistic site-controlled (111)-oriented InGaAs/GaAs quantum dots. Special attention is paid to the impact of random alloy fluctuations on…

Materials Science · Physics 2016-09-16 R. Benchamekh , S. Schulz , E. P. O'Reilly

Using 3D k.p calculation including strain and piezoelectricity we predict variation of electronic and optical properties of InAs/GaAs quantum dots (QDs) with the substrate orientation. The QD transition energies are obtained for high index…

Materials Science · Physics 2015-06-25 V. Mlinar , F. M. Peeters

We present a detailed investigation into the optical characteristics of individual InAs quantum dots (QDs) grown by metalorganic chemical vapor deposition, with low temperature emission in the telecoms window around 1300 nm. Using…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 N. I. Cade , H. Gotoh , H. Kamada , H. Nakano , H. Okamoto

We present a comprehensive study of quantum dot (QD) coupling to various phononic modes in a phononic waveguide, combining multiband kp and configuration-interaction (CI) QD state simulations with finite-element waveguide mode modeling. We…

Mesoscale and Nanoscale Physics · Physics 2026-01-21 Jakub Rosiński , Michał Gawełczyk , Matthias Weiß , Hubert J. Krenner , Paweł Machnikowski
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