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One-dimensional (1D) quantum systems are a cornerstone of many-body physics. However, their realization in solids has traditionally relied on top-down methods, which are limited by structural disorder and coarse confinement. Here, we…

The multiplication rates of hot carriers in CdSe quantum dots are quantified using an atomistic pseudopotential approach and first order perturbation theory. Both excited holes and electrons are considered, and electron-hole Coulomb…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Zhibin Lin , Alberto Franceschetti , Mark T. Lusk

Optical harmonic generation on excitons is found in ZnSe/BeTe quantum wells with type-II band alignment. Two experimental approaches with spectrally-broad femtosecond laser pulses and spectrally-narrow picosecond pulses are used for…

Time-dependent density functional theory (TDDFT) has been applied to the calculation of absorption spectra for two-dimensional atomic layer materials. We reveal that the character of the first bright exciton state of bi-layer hexagonal…

Materials Science · Physics 2020-01-08 Yasumitsu Suzuki , Kazuyuki Watanabe

Controlling light emission at the nanoscale has important applications in solid-state lighting, displays, and quantum light sources. Achieving this control requires both enhanced local electromagnetic fields to boost emission intensity and…

Stable excitons in semiconductor monolayers such as transition-metal dichalcogenides (TMDCs) enable and motivate fundamental research as well as the development of room-temperature optoelectronics applications. The newly discovered layered…

Materials Science · Physics 2021-03-17 Magdalena Birowska , Paulo E. Faria Junior , Jaroslav Fabian , Jens Kunstmann

The electronic band structure of Na$_{2}$KSb was studied by a combination of low-energy photoemission spectroscopy and density functional theory (DFT) calculations. The optical and photoemission quantum efficiency (QE) spectra, along with…

Colloidal semiconductor nanoplatelets exhibit quantum size effects due to their thickness of only few monolayers, together with strong optical band-edge transitions facilitated by large lateral extensions. In this article we demonstrate…

We have studied emission properties of high-density excitons in single-walled carbon nanotubes through nonlinear photoluminescence excitation spectroscopy. As the excitation intensity was increased, all emission peaks arising from different…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Y. Murakami , J. Kono

Characteristics of the primary fragments produced in central collisions of 129Xe + natSn from 32 to 50 AMeV have been obtained. By using the correlation technique for the relative velocity between light charged particles (LCP) and…

Nuclear Experiment · Physics 2009-11-07 S. Hudan , A. Chbihi , J. D. Frankland , A. Mignon , J. P. Wieleczko

Two-dimensional (2D) semiconductors are promising candidates for optoelectronic application and quantum information processes due to their inherent out-of-plane 2D confinement. In addition, they offer the possibility of achieving…

Using an approximate time-dependent density functional theory method, we calculate the absorption and luminescence spectra for hydrogen passivated silicon nanoscale structures with large aspect ratio. The effect of electron confinement in…

Materials Science · Physics 2009-09-27 Y. Wang , R. Q. Zhang , Th. Frauenheim , T. A. Niehaus

This work presents epitaxial growth and optical spectroscopy of CdTe quantum dots (QDs) in (Cd,Zn,Mg)Te barriers placed on the top of (Cd,Zn,Mg)Te distributed Bragg reflector. The formed photonic mode in our half-cavity structure permits to…

Mesoscale and Nanoscale Physics · Physics 2017-03-24 W. Pacuski , J. -G. Rousset , V. Delmonte , T. Jakubczyk , K. Sobczak , J. Borysiuk , K. Sawicki , E. Janik , J. Kasprzak

Precise predictions for nuclei near drip lines are crucial for experiments in new generation of rare isotope facilities. A multi-models investigation of the $Q_g$ systematics for fragments production cross sections, with $Q_g$ defined as…

A giant built-in electric field in the growth direction makes excitons in wide GaN/(Al, Ga)N quantum wells spatially indirect even in the absence of any external bias. Significant densities of indirect excitons can accumulate in…

We develop a full-wave electromagnetic (EM) theory for calculating the multipole decomposition in two-dimensional (2-D) structures consisting of isolated, arbitrarily shaped, inhomogeneous, anisotropic cylinders or a collection of such. To…

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 demonstrate on chip generation of correlated pairs of photons in the near-visible spectrum using a CMOS compatible PECVD Silicon Nitride photonic device. Photons are generated via spontaneous four wave mixing enhanced by a ring resonator…

Quantum Physics · Physics 2018-03-29 Robert Cernansky , Francesco Martini , Alberto Politi

Simulations of exciton and charge hopping in amorphous organic materials involve numerous physical parameters. Each of these parameters must be computed from costly ab initio calculations before the simulation can commence, resulting in a…

A fundamental building block for on-chip quantum photonics is a single-photon source with high repetition rates, which can enable many applications such as high-speed quantum communication and quantum information processing. Ideally, such…