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Cathodoluminescence measurements on single InGaN/GaN quantum dots (QDs) are reported. Complex spectra with up to five emission lines per QD are observed. The lines are polarized along the orthogonal crystal directions [1 1 -2 0] and [-1 1 0…

Materials Science · Physics 2007-06-14 M. Winkelnkemper , R. Seguin , S. Rodt , A. Schliwa , L. Reissmann , A. Strittmatter , A. Hoffmann , D. Bimberg

Strongly-coupled quantum dot molecules (QDMs) are widely deployed in the design of a variety of optoelectronic, photovoltaic, and quantum information devices. An efficient and optimized performance of these devices demands engineering of…

Mesoscale and Nanoscale Physics · Physics 2015-10-28 Muhammad Usman

We report on photon coincidence measurement in a single GaAs self-assembled quantum dot (QD) using a pulsed excitation light source. At low excitation, when a neutral exciton line was present in the photoluminescence (PL) spectrum, we…

We apply magnetic fields of up to 7 T to an indium arsenide (InAs) quantum dot (QD) strongly coupled to a photonic crystal cavity. The field lifts the degeneracy of QD exciton spin states, and tune their emission energy by a combination of…

Quantum Physics · Physics 2011-01-05 Hyochul Kim , Thomas C. Shen , Deepak Sridharan , Glenn S. Solomon , Edo Waks

We study the electronic coupling between two vertically stacked InAs quantum dots, which are embedded in the center of a n-i-n structure. We use a micro-photoluminescence setup to optically isolate a single quantum dot pair and measure the…

Strongly Correlated Electrons · Physics 2009-11-07 I. Shtrichman , C. Metzner , B. D. Gerardot , W. V. Schoenfeld , P. M. Petroff

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

Due to their band-structure and optical properties, InAs/InP quantum dots (QDs) constitute a promising system for single-photon generation at third telecom window of silica fibers and for applications in quantum communication networks.…

Mesoscale and Nanoscale Physics · Physics 2020-05-20 P. Holewa , M. Gawełczyk , C. Ciostek , P. Wyborski , S. Kadkhodazadeh , E. Semenova , M. Syperek

In this work the intersubband electronic properties of two laterally coupled dome-shaped InAs/GaAs quantum dots were investigated. The envelope functions and eigenenergies were calculated as function of distance between the dots. The…

Materials Science · Physics 2013-12-12 A. Khaledi-Nasab , M. Shahzadeh , H. Amouzegar , M. Sabaeian

We report on linewidth analysis of optical transitions in InAs/GaAs coupled quantum dots as a function of bias voltage, temperature, and tunnel coupling strength. A significant line broadening up to 100 $\mu$eV is observed at hole tunneling…

Mesoscale and Nanoscale Physics · Physics 2020-08-25 P. Kumar , C. Jennings , M. Scheibner , A. S. Bracker , S. G. Carter , D. Gammon

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

The exciton recombination and spin dynamics in (In,Al)As/AlAs quantum dots (QDs) with indirect band gap and type-I band alignment are studied. The negligible (less than $0.2~\mu$eV) value of the anisotropic exchange interaction in these QDs…

Mesoscale and Nanoscale Physics · Physics 2023-01-27 T. S. Shamirzaev , A. V. Shumilin , D. S. Smirnov , D. Kudlacik , S. V. Nekrasov , Yu. G. Kusrayev , D. R. Yakovlev , M. Bayer

By the application of an in-plane magnetic field, we demonstrate control of the fine structure polarisation splitting of the exciton emission lines in individual InAs quantum dots. The selection of quantum dots with certain barrier…

Scattering of carriers between spatially separated zero dimensional states has been observed in a system of self-assembled In_{0.55}Al_{0.45}As quantum dots. We believe the interdot tunneling is mediated by localized states below the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 H. D. Robinson , B. B. Goldberg , J. L. Merz

We observe the low-lying excitations of a molecular dimer formed by two electrons in a GaAs semiconductor quantum dot in which the number of confined electrons is tuned by optical illumination. By employing inelastic light scattering we…

Mesoscale and Nanoscale Physics · Physics 2010-06-16 Achintya Singha , Vittorio Pellegrini , Aron Pinczuk , Loren N. Pfeiffer , Ken W. West , Massimo Rontani

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

Exciton, trion and biexciton dephasing rates are measured within the inhomogeneous distribution of an InAs quantum dot (QD) ensemble using two-dimensional Fourier-transform spectroscopy. The dephasing rate of each excitonic state is similar…

Mesoscale and Nanoscale Physics · Physics 2014-09-30 G. Moody , R. Singh , H. Li , I. A. Akimov , M. Bayer , D. Reuter , A. D. Wieck , S. T. Cundiff

Engineering the coupling between fundamental quantum excitations is at the heart of quantum science and technologies. A significant case is the creation of quantum light sources in which coupling between single photons and phonons can be…

Mesoscale and Nanoscale Physics · Physics 2023-02-28 Adina Ripin , Ruoming Peng , Xiaowei Zhang , Srivatsa Chakravarthi , Minhao He , Xiaodong Xu , Kai-Mei Fu , Ting Cao , Mo Li

We use co-tunneling spectroscopy to investigate spin-, orbital-, and spin-orbital Kondo transport in a strongly confined system of InAs double quantum dots (QDs) parallel-coupled to source and drain. In the one-electron transport regime,…

Mesoscale and Nanoscale Physics · Physics 2020-04-08 Heidi Potts , Martin Leijnse , Adam Burke , Malin Nilsson , Sebastian Lehmann , Kimberly A. Dick , Claes Thelander

Optical transitions in coupled InAs/InP self-assembled quantum wires are studied within the single-band effective mass approximation including effects due to strain. Both vertically and horizontally coupled quantum wires are investigated…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. Sidor , B. Partoens , F. M. Peeters , T. Ben , A. Ponce , D. L. Sales , S. I. Molina , D. Fuster , L. Gonzalez , Y. Gonzalez

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