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Related papers: Excitons in InP, GaP, GaInP quantum dots: Insights…

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The optical response of (InGa)(AsSb)/GaAs quantum dots (QDs) grown on GaP (001) substrates is studied by means of excitation and temperature-dependent photoluminescence (PL), and it is related to their complex electronic structure. Such QDs…

Mesoscale and Nanoscale Physics · Physics 2019-11-13 Petr Steindl , Elisa Maddalena Sala , Benito Alén , David Fuertes Marrón , Dieter Bimberg , Petr Klenovský

We have studied the emission properties of self-organized InAs quantum dots (QDs) grown in an InGaAs quantum well by metalorganic chemical vapor deposition. Low-temperature photoluminescence spectroscopy shows emission from single QDs…

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

Detailed theoretical studies of the electronic structure of (InGa)(AsSb)/GaAs/GaP quantum dots are presented. This system is unique since it exhibits concurrently direct and indirect transitions both in real and momentum space and is…

Mesoscale and Nanoscale Physics · Physics 2019-09-18 Petr Klenovský , Andrei Schliwa , Dieter Bimberg

The theory of exciton coupling to photons and LO phonons in quantum dots (QDs) and quantum-dot molecules (QDMs) is presented. Resonant-round trips of the exciton between the ground (bright) and excited (dark or bright) states mediated by…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Kuan-Ming Hung

Electron states in a quantum dot (QD) located near a 2D system of dipolar excitons are perturbed by fluctuations of the exciton density caused by the electron-exciton interaction. This results in the frequency changes of electron…

Mesoscale and Nanoscale Physics · Physics 2021-05-19 M. M. Mahmoodian , A. V. Chaplik

Charge-transfer excitons possessing long radiative lifetime and net permanent dipole moment are highly appealing for quantum dot (QD) based energy harvesting and photodetecting devices, in which the efficiency of charge separation after…

Mesoscale and Nanoscale Physics · Physics 2022-07-13 Yamei Zhou , Christos S. Garoufalis , Zaiping Zeng , Sotirios Baskoutas , Yu Jia , Zuliang Du

We present a theory of excitonic processes in gate controlled graphene quantum dots. The dependence of the energy gap on shape, size and edge for graphene quantum dots with up to a million atoms is predicted. Using a combination of…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 A. D. Guclu , P. Potasz , P. Hawrylak

Excitonic fine structure splitting in quantum dots is closely related to the lateral shape of the wave functions. We have studied theoretically the fine structure splitting in InAs quantum dots with a type-II confinement imposed by a GaAsSb…

Mesoscale and Nanoscale Physics · Physics 2015-12-02 Vlastimil Křápek , Petr Klenovský , Tomáš Šikola

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

Free standing InP quantum dots have previously been theoretically and experimentally shown to have a direct band gap across a large range of experimentally accessible sizes. We demonstrate that when these dots are embedded coherently within…

Materials Science · Physics 2009-10-31 A. J. Williamson , Alex Zunger , A. Canning

Exciton fine structures in cubic III-V semiconductor GaAs, InAs and GaN quantum dots are investigated systematically and the exciton spin relaxation in GaN quantum dots is calculated by first setting up the effective exciton Hamiltonian.…

Mesoscale and Nanoscale Physics · Physics 2011-06-15 H. Tong , M. W. Wu

We investigate experimentally and theoretically few-particle effects in the optical spectra of single quantum dots (QDs). Photo-depletion of the QD together with the slow hopping transport of impurity-bound electrons back to the QD are…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Arno Hartmann , Yann Ducommun , Eli Kapon , Ulrich Hohenester , Elisa Molinari

We present an eight-band k.p model for the calculation of the electronic structure of wurtzite semiconductor quantum dots (QDs) and its application to indium gallium nitride (InGaN) QDs formed by composition fluctuations in InGaN layers.…

Materials Science · Physics 2007-05-23 Momme Winkelnkemper , Andrei Schliwa , Dieter Bimberg

We describe the optical emission and the carrier dynamics of an ensemble of self-assembled GaAs quantum dots embedded in GaP(001). The QD formation is driven by the 3.6 % lattice mismatch between GaAs and GaP in Stranski-Krastanow mode…

Mesoscale and Nanoscale Physics · Physics 2016-03-23 S. Dadgostar , J. Schmidtbauer , T. Boeck , A. Torres , O. Martínez , J. Jiménez , J. W. Tomm , A. Mogilatenko , W. T. Masselink , F. Hatami

We develop a temperature dependent empirical pseudopotential theory to study the electronic and optical properties of self-assembled quantum dots (QDs) at finite temperature. The theory takes the effects of both lattice expansion and…

Materials Science · Physics 2015-06-04 Jianping Wang , Ming Gong , Guang-Can Guo , Lixin He

We study the optical properties of hydrogen passivated silicon, germanium and mixed Ge/Si core/shell quantum dots (QDs) using high accuracy Density Functional Theory (DFT) and time-dependent DFT (TDFT). We employ the hybrid DFT functional…

Mesoscale and Nanoscale Physics · Physics 2016-04-19 Shanawer Niaz , Aristides D. Zdetsis , Manzoor Ahmad Badar , Safdar Hussain , Imran Sadiq , Muhammad Aslam Khan

The spin structure and spin dynamics of excitons in an ensemble of (In,Al)As/AlAs quantum dots (QDs) with type-I band alignment, containing both direct and indirect band gap dots, are studied. Time-resolved and spectral selective techniques…

Mesoscale and Nanoscale Physics · Physics 2019-05-15 J. Rautert , T. S. Shamirzaev , S. V. Nekrasov , D. R. Yakovlev , P. Klenovský , Yu. G. Kusrayev , M. Bayer

Electron transfer to an individual quantum dot promotes the formation of charged excitons with enhanced recombination pathways and reduced lifetimes. Excitons with only one or two extra charges have been observed and exploited for very…

We demonstrate electromagnetic interaction between distant quantum dots (QDs), as is observed from transient pump-probe differential reflectivity measurements. The QD-exciton lifetime is measured as a function of the probe photon energy and…

Other Condensed Matter · Physics 2009-11-11 E. W. Bogaart , J. E. M. Haverkort , R. Noetzel

Quantum dots are arguably one of the best platforms for optically accessible spin based qubits. The paramount demand of extended qubit storage time can be met by using quantum-dot-confined dark exciton: a longlived electron-hole pair with…

Mesoscale and Nanoscale Physics · Physics 2021-04-28 Michał Zieliński