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We probe the electron transport properties in the shell of GaAs/In0.2Ga0.8As core/shell nanowires at high electric fields using optical pump / THz probe spectroscopy with broadband THz pulses and peak electric fields up to 0.6 MV/cm. The…

Mesoscale and Nanoscale Physics · Physics 2020-06-24 Rakesh Rana , Leila Balaghi , Ivan Fotev , Harald Schneider , Manfred Helm , Emmanouil Dimakis , Alexej Pashkin

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

Nanowire-based light-emitting devices require multi-quantum well heterostructures with high room temperature optical efficiencies. We demonstrate that such efficiencies can be attained through the use of ZnO/Zn(1-x)MgxO core shell quantum…

Core-shell nanorods (NRs) with InGaN/GaN quantum wells (QWs) are promising for monolithic white light-emitting diodes and multicolor displays. Such applications, however, are still a challenge because intensity of red band is too weak as…

After making a cold weld by pressing two clean metal surfaces together, upon gradually separating the two pieces a metallic nanowire is formed, which progressively thins down to a single atom before contact is lost. In previous experiments…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 A. I. Yanson , I. K. Yanson , J. M. van Ruitenbeek

Nanowire double quantum dots occupied by an even number of electrons are investigated in the context of energy level structure revealed by electric dipole spin resonance measurements. We use numerically exact configuration interaction…

Mesoscale and Nanoscale Physics · Physics 2015-03-05 M. P. Nowak , B. Szafran

GaAs nanowires and GaAs-Fe3Si core-shell nanowire structures were grown by molecular-beam epitaxy on oxidized Si(111) substrates and characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Ga droplets were…

Materials Science · Physics 2015-12-10 Bernd Jenichen , Maria Hilse , Jens Herfort , Achim Trampert

We present a symmetry-based calculation of the electronic structure of a compound semiconductor quantum dot (QD) in the sp^3s* tight-binding model including the spin-orbit interaction. The Hamiltonian matrix is diagonalized exactly for CdTe…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 J. Perez-Conde , A. K. Bhattacharjee

The electronic structure of nanowires in contact with metallic electrodes of experimentally relevant sizes is calculated by incorporating the electrostatic polarization potential into the atomistic single particle Schr\"odinger equation. We…

Materials Science · Physics 2015-05-13 Denis O. Demchenko , Lin-Wang Wang

We supplement our previous observations of the shell effect in alkali-metal nanowires (Li, Na, K) with data extended to the heavy alkalis Rb and Cs. Our observations include: i) a non-monotonous dependence of conductance-histogram peak…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. I. Yanson , I. K. Yanson , J. M. van Ruitenbeek

Band structure is theoretically studied in partially flattened carbon nanotubes within an effective-mass scheme. Effects of inter-wall interactions are shown to be important in non-chiral nanotubes such as zigzag and armchair and can…

Mesoscale and Nanoscale Physics · Physics 2016-10-12 Takeshi Nakanishi , Tsuneya Ando

The optical properties of a stack of GaN/AlN quantum discs (QDiscs) in a GaN nanowire have been studied by spatially resolved cathodoluminescence (CL) at the nanoscale (nanoCL) using a Scanning Transmission Electron Microscope (STEM)…

Materials Science · Physics 2015-02-10 L. F. Zagonel , L. Rigutti , M. Tchernycheva , G. Jacopin , R. Songmuang , M. Kociak

The electronic band structure of complex nanostructured semiconductors has a considerable effect on the final electronic and optical properties of the material and, ultimately, on the functionality of the devices incorporating them. Valence…

Poly(ethylene imine) functionalized carbon nanotube thin films, prepared using the vacuum filtration method, were decorated with Au nanoparticles by in situ reduction of HAuCl4 under mild conditions. These Au nanoparticles were subsequently…

Materials Science · Physics 2008-12-16 P. K. Mohseni , G. Lawson , C. Couteau , G. Weihs , A. Adronov , R. R. LaPierre

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

Tunneling of electrons through the barriers in heterostructures devices is investigated by using the unified Transfer Matrix Method. The effect of barrier width on electron transmission coefficients has also been examined for different…

Mesoscale and Nanoscale Physics · Physics 2022-03-28 Jatindranath Gain , Madhumita Dassarkar , Sudakhina Kundu

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…

Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate…

Mesoscale and Nanoscale Physics · Physics 2020-12-30 Florinda Viñas Boström , Athanasios Tsintzis , Michael Hell , Martin Leijnse

An early-stage version of simulation package ' ELSES' (Extra-Large-Scale Electronic-Structure calculation) is developed for electronic structure and dynamics of large systems, particularly, nm-scale or 10nm-scale systems (www.elses.jp).…

Materials Science · Physics 2009-06-16 Takeo Hoshi , Takeo Fujiwara

We observe a systematic red shift of the band-edge of passivated GaAs/Al0.35Ga0.65As core-shell nanowires with increasing shell thickness up to 100 nm. The shift is detected both in emission and absorption experiments, reaching values up to…