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The two- to three-dimensional growth transition in the InAs/GaAs(001) heterostructure has been investigated by atomic force microscopy. The kinetics of the density of three dimensional quantum dots evidences two transition thresholds at…

Materials Science · Physics 2009-11-11 F. Arciprete , E. Placidi , V. Sessi , M. Fanfoni , F. Patella , A. Balzarotti

We report a correlative microscopy study of a sample containing three stacks of InGaN/GaN quantum dots (QDs) grown at different substrate temperature, each stack consisting of 3 layers of QDs. Decreasing the substrate temperature along the…

Materials Science · Physics 2021-06-08 I. Dimkou , J. Houard , N. Rochat , P. Dalapati , E. Di Russo , D. Cooper , A. Grenier , E. Monroy , L. Rigutti

We investigate site-controlled In$_{0.25}$Ga$_{0.75}$As quantum dots in (111)B GaAs pyramidal recesses as spin qubits. Combining scanning confocal cryomicroscopy, magneto-photoluminescence studies and resonant excitation, we identify and…

Mesoscale and Nanoscale Physics · Physics 2025-09-09 R. A. Barcan , I. Samaras , K. Barr , G. Juska , E. Pelucchi , K. G. Lagoudakis

Electronic structures for InxGa1-xAs nanowires with [100], [110], and [111] orientations and critical dimensions of approximately 2 nm are treated within the framework of density functional theory. Explicit band structures are calculated…

Mesoscale and Nanoscale Physics · Physics 2018-02-23 Pedram Razavi , James C. Greer

The formation of nanostructures during metalorganic vapor-phase epitaxy on patterned (001)/(111)B GaAs substrates is reviewed. The focus of this review is on the seminal experiments that revealed the key kinetic processes during…

Mesoscale and Nanoscale Physics · Physics 2018-02-09 Emanuele Pelucchi , Stefano T. Moroni , Valeria Dimastrodonato , Dimitri D. Vvedensky

The quantum states of an ellipsoidal nanocluster of a heterophase system InAs / GaAs are studied using an exact analytical approach, in contrast to the generally accepted theoretical model based on the adiabatic approximation. It is shown…

Mesoscale and Nanoscale Physics · Physics 2024-04-04 G. Nikoghosyan , H. S. Nikoghosyan

This work presents a selective ultraviolet (UV)-ozone oxidation-chemical etching process that has been used, in combination with laser interference lithography (LIL), for the preparation of GaAs patterned substrates. Further molecular beam…

We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 W. Y. Mak , F. Sfigakis , K. Das Gupta , O. Klochan , H. E. Beere , I. Farrer , J. P. Griffiths , G. A. C. Jones , A. R. Hamilton , D. A. Ritchie

The photoluminescence polarizations of (In,Ga)As/GaAs quantum dots annealed at different temperatures are studied as a function of external magnetic field (Hanle curves). In these dependencies, remarkable resonant features appear due to…

Excitons confined to flat semiconductor quantum dots with elliptical cross section are considered as we study geometrical effects on exciton binding energy, electron-hole separation, and the resulting linear optical properties. We use…

Condensed Matter · Physics 2009-10-28 Jakyoung Song , Sergio E. Ulloa

We study the optical properties of highly anisotropic quantum dot structures (quantum dashes) characterized by the presence of two trapping centers located along the structure. Such a system can exhibit some of the properties characteristic…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 Piotr Kaczmarkiewicz , Paweł Machnikowski , Tilmann Kuhn

We present a novel "linear combination of atomic orbitals"-type of approximation, enabling accurate electronic structure calculations for systems of up to 20 or more electronically coupled quantum dots. Using realistic single quantum dot…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Alexander Mittelstädt , Ludwig A. Th. Greif , Stefan T. Jagsch , Andrei Schliwa

Quantum dots exhibit reproducible conductance fluctuations at low temperatures due to electron quantum interference. The sensitivity of these fluctuations to the underlying disorder potential has only recently been fully realized. We…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 A. M. See , M. Aagesen , P. E. Lindelof , A. R. Hamilton , A. P. Micolich

We investigate theoretically the slowdown of optical pulses due to quantum-coherence effects in InGaAs-based quantum dots and quantum dot molecules. Simple models for the electronic structure of quantum dots and, in particular, quantum-dot…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Stephan Michael , Weng W. Chow , Hans Christian Schneider

We theoretically study the optical properties and the electronic structure of highly elongated quantum dots (quantum dashes) and show how carrier trapping due to geometrical fluctuations of the confining potential affects the excitonic…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Piotr Kaczmarkiewicz , Paweł Machnikowski

Core-shell GaAs-based nanowires monolithically integrated on Si constitute a promising class of nanostructures that could enable light emitters for fast inter- and intrachip optical connections. We introduce and fabricate a novel coaxial…

Self-assembled InAs quantum dots (QDs) are promising optomechanical elements due to their excellent photonic properties and sensitivity to local strain fields. Microwave-frequency modulation of photons scattered from these efficient quantum…

The electronic structure of strain-engineered single InGaAs/GaAs quantum dots emitting in the telecommunication O band is probed experimentally by photoluminescence excitation spectroscopy. Observed resonances can be attributed to p-shell…

Dense arrays of semiconductor quantum dots are currently employed in highly efficient quantum dot lasers for data communications and other applications. Traditionally, the electronic properties of such quantum nanostructures have been…

Mesoscale and Nanoscale Physics · Physics 2024-12-02 Christopher Natale , Ethan Diak , Ray LaPierre , Ryan B. Lewis

Growth of GaAs and InGaAs nanowires by the group-III assisted Molecular Beam Epitaxy growth method is studied in dependence of growth temperature, with the objective of maximizing the indium incorporation. Nanowire growth was achieved for…