Cage effect on the photodissociation of small molecules in rare gas matrices

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InGaN/GaN-based light-emitting diodes (LEDs) exhibit remarkable tolerance to high threading dislocation densities (TDDs), maintaining internal quantum efficiencies above 90% at room temperature even with TDD exceeding 108 cm−2. This robustness is attributed to V-shaped pits (V-pits), which form around threading dislocations (TDs) in InGaN/GaN quantum wells (QWs) and create potential barriers that inhibit carrier diffusion toward non-radiative dislocation cores. However, assessing the intrinsic non-radiative

At the microscopic level, the behaviour of a solid is governed by the intricate interplay between electrons, the lattice, and, in some cases, spin degrees of freedom. From these interactions emerge collective excitations involving charge, lattice, and spin dynamics, known respectively as plasmons, phonons, and magnons. These quasiparticles and their mutual couplings can only be described within a quantum mechanical framework, from which arise a variety of exotic phases of matter. Light-matter interaction of

A quantum dot device (100) for use as a qubit in a quantum computer is disclosed, comprising a channel region (106), a source region (108), a drain region (110), and at least two primary gate regions (120, 122, 124), wherein the at least two primary gate regions (120, 122, 124) are respectively provided with a main direction of extension (126, 128, 130) and disposed on a first surface of the channel region (106), and wherein the respective main directions of extension of the at least two primary gate region

We present QuantumToolbox.jl, an open-source Julia package for simulating open quantum systems. Designed with a syntax familiar to users of QuTiP (Quantum Toolbox in Python), it harnesses Julia's high-performance ecosystem to deliver fast and scalable simulations. The package includes a suite of time-evolution solvers supporting distributed computing and GPU acceleration, enabling efficient simulation of large-scale quantum systems. We also show how QuantumToolbox.jl can integrate with automatic differentia

This study shows that the surface modification of TiO2 is an effective route to increase the TiO2 absorption in the visible region up to similar to 600 nm for photocatalytic applications. The In2O3 decorated TiO2 films on polyester obtained by reactive sputtering were shown to accelerate the Escherichia coli inactivation under actinic and simulated solar light. TiO2 sputtered films for 10 min inactivated bacteria within 300 min under actinic light. The inactivation time was reduced when using a TiO2 10 min-

The effect of the miscut angle of vicinal substrate on the optical and morphological properties of GaAs/AlxGa1-xAs quantum wells grown by metalorganic vapor phase epitaxy is studied by means of photoluminescence (PL) and atomic force microscopy. Within small changes of the miscut angle, we observe strong variations of the PL linewidth, energy, and lineshape, as well as transitions between the morphology of the sample's surface and interface. The relation between these features is discussed, and the particul

Based on site- and energy-controlled quantum wires (QWR) and quantum dots (QD), diverse photonic-crystal microcavity laser systems are proposed and discussed. Results demonstrating QWR lasing, cavity coupling and QD ordered arrays are presented.

We are progressively approaching the physical limits of microcavity LEDs (MC-LEDs) for high brightness, high efficiency LEDs. They are promising high efficiency devices and they offer the very attractive prospect of full planar fabrication process. However, to compete with other high efficiency LED schemes, they need to approach or surpass the 50 % efficiency mark. We first explore the limits of planar MC-LEDs in both the GaAllnAsP and GaInAlN materials systems, and show that the single-step extraction limi

In this paper, we present a systematic study of the effect of growth parameters on the structural and optical properties of InAs quantum dot (QD) grown under Stranski-Krastanov mode by molecular beam epitaxy. The dot density is significantly reduced from 1.9x10(10) to 0.6x10(10) cm(-2) as the growth rate decreases from 0.075 to 0.019 ML/s, while the island size becomes larger. Correspondingly, the emission wavelength shifts to the longer side. By increasing the indium fraction in the InGaAs capping layer, t

The purpose of my thesis is to provide a theoretical analysis of the dynamics of optically excited carriers in semiconductor confined systems. In particular, I will focus the investigations on the effects due to the presence of a strong electron-hole Coulomb correlation. The Coulomb interaction leads to the formation of hydrogen-like bound states called excitons. The dynamics of these states is investigated in bare and cavity embedded quantum wells, and in quantum wires. I have investigated the dynamics of

We investigate the exciton formation process from free carriers in a single GaAs quantum well. We focus on the formation processes assisted by emission and absorption of acoustic and optical phonons. The formation rates are evaluated and compared to the experimental results. The exciton dissociation rates are also calculated as a function of the lattice temperature. Finally, these rates are used in a rate equation model in order to reproduce the dynamics of excitons and free carriers in a photoluminescence

Dissocn. efficiencies for excitation of the repulsive A 1P state of HCl were recorded in Xe, Kr, and Ar matrixes for photon energies between 5 and 10 eV from the content of dissocn. products and quantum efficiencies were derived with the absorption spectra. Influence of temp. and prepn. conditions was investigated. The quantum efficiency rises monotonically in Xe from an excess energy of 1.4 eV above the gas phase dissocn. energy on, sats. around 2.4 eV and remains then essentially const. up to 4 eV. In Ar

We present recent results of the study of surface properties and quantum efficiency (QE) of CsI photocathodes prepared on various substrates. Microanalysis methods provide laterally resolved surface morphology and chemical composition of the photoemissive film. Integral measurements of the QE of CsI were done with a monochromator system and a RICH device. It was shown that CsI films deposited on large area Ni- or Ni-Au-coated printed circuit electrodes have a uniform crystalline structure and an average QE

Cage effect on the photodissociation of small molecules in rare gas matrices

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Evidence of the non-radiative character of dislocations in V-pit-free InGaN/GaN quantum wells

Collective mode dynamics in quantum materials probed by ultrafast electron diffraction

Field-effect transistor element and quantum computer device

QuantumToolbox.jl: An efficient Julia framework for simulating open quantum systems

Uniform TiO2/In2O3 surface films effective in bacterial inactivation under visible light

Optics, morphology, and growth kinetics of GaAs/Al_{x}Ga_{1-x}As quantum wells grown on vicinal substrates by metalorganic vapor phase epitaxy

Site-Controlled Quantum-Wire and Quantum-Dot Photonic-Crystal Microcavity Lasers

Recent results and latest views on microcavity LEDs

Tuning InAs/GaAs quantum dot properties under Stranski-Krastanov growth mode for 1.3 mu m applications

Exciton dynamics in semiconductor confined systems

Role of carrier-phonon interaction on the exciton formation in quantum wells

Cage exit probability versus excess energy in the photodissociation of matrix-isolated HCl

Microanalysis surface studies and photoemission properties of CsI photocathodes