The negatively charged exciton ${\mathit{X}}^{\mathrm{\ensuremath{-}}}$ is identified by its circular polarization properties in 1.7 K magentoabsorption spectra of CdTe/${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Zn}}_{\mathit{x}}$Te multiple quantum wells modulation doped with electron concentrations ${\mathit{N}}_{\mathit{s}}$\ensuremath{\approxeq}2\ifmmode\times\else\texttimes\fi{}${10}^{10}$ to 1.5\ifmmode\times\else\texttimes\fi{}${10}^{11}$...

We study the effect of exciton-acoustic-phonon coupling on optical homogeneous line shape confined zero-dimensional excitons and discuss connection with so-called pure dephasing effect. On increasing temperature, progressively deviates from expected Lorentzian profile, appearance low energy acoustic-phonon sidebands. The non-Lorentzian its temperature dependence are theoretically modeled basis lattice relaxation due to coupling. This gives a precise description underlying mechanism which...

A method for growing self-assembled II–VI quantum dots (QDs) is demonstrated: highly strained CdTe layer, grown onto Zn(Mg)Te, covered with an amorphous Te layer which then desorbed. This induces QD formation, observed as abrupt change of both the reflection high-energy electron diffraction pattern and surface morphology studied by atomic force microscopy in ultrahigh vacuum. The are also characterized after capping microphotoluminescence. transition, occurs not during growth, can be...

We present a high-temperature single-photon source based on quantum dot inside nanowire. The nanowires were grown by molecular beam epitaxy in the vapor-liquid-solid growth mode. utilize two-step process that allows thin, defect-free ZnSe nanowire to grow top of broader, cone-shaped Quantum dots are formed incorporating narrow zone CdSe into observe intense and highly polarized photoluminescence even from single emitter. Efficient photon antibunching is observed up 220 K, while conserving...

Epitaxial semiconductor quantum dots are particularly promising as realistic single-photon sources for their compatibility with manufacturing techniques and possibility to be implemented in compact devices. Here, we demonstrate the first time emission up room temperature from an epitaxial dot inserted a nanowire, namely CdSe slice ZnSe nanowire. The exciton biexciton lines can still resolved at turns out most appropriate transition due large nonradiative decay of bright dark states. With...

We report a microphotoluminescence study of the exciton and biexciton localized in very elongated islands formed by well-width fluctuations thin CdTe/CdMgTe quantum well grown on vicinal surface. The electron-hole exchange interaction local reduced symmetry splits states. resulting transitions are linearly polarized along two orthogonal principal axes island. valence band mixing induced shape potential leads to strong polarization anisotropy observation dark states under magnetic field....

Optical emission from individual, n-type modulation-doped CdTe quantum dots (QD's) is presented. Magnetomicrophotoluminescence and power-excitation-dependent measurements allows one to identify the neutral exciton, negatively charged biexciton. All these few-particle species are exposed randomly fluctuating electric fields attributed charges trapped in vicinity of QD. The resulting confined Stark effect, characteristic for each dot, analyzed detail. correlations between energies exciton as...

Biocompatibility, biofunctionality, and chemical stability are essential criteria to be fulfilled by quantum dot (QD) emitters for bio-imaging -sensing applications. In addition these criteria, achieving efficient near-infrared (NIR) emission with nontoxic QDs remains very challenging. this perspective, we developed water-soluble NIR-emitting AgInS2/ZnS core/shell (AIS/ZnS) functionalized DNA. The newly established aqueous route relying on a two-step hot-injection synthesis led highly...

Photoluminescence of a single CdSe quantum dot embedded in ZnSe nanowire has been investigated. It found that the dark exciton strong influence on optical properties. The most visible is strongly reduced excitonic emission compared to biexcitonic one. Temperature dependent lifetime measurements have allowed us measure large splitting $\Delta E = 6 $ meV between and bright as well spin flip rates these two states.

We have studied spectral diffusion of the photoluminescence a single CdSe quantum dot inserted in ZnSe nanowire. measured characteristic time as function pumping power and temperature using recently developed technique [G. Sallen et al., Nat. Photon. 4, 696 (2010)] that offers subnanosecond resolution. These data are consistent with model where only carrier wanders around traps located vicinity dot.

Thin CdTe layers embedded in ZnTe matrix grown by atomic layer epitaxy have been studied time resolved spectroscopy and spatially spectroscopy. The presence of Cd-rich dotlike islands these nanostructures is shown both force microscopy high resolution transmission electron microscopy. Zero-dimensional nature excitons the temperature dependence decay observation sharp exciton lines microphotoluminescence spectra. probed present a doublet structure linearly polarized along two orthogonal...

Quantum dots are promising building blocks for future optoelectronics or quantum information applications. Many of their properties derive from the state hole trapped in dot. ``Light'' and ``heavy'' states differ by anisotropic character spin electric dipole they form with a electron. Light holes particular interest as offer extended opportunities optical manipulation single carriers, electrical magnetic objects. Here, authors demonstrate that ground can be engineered through proper design...

We report correlation and cross-correlation measurements of photons emitted under continuous wave excitation by a single II-VI quantum dot (QD) grown molecular-beam epitaxy. A standard technique microphotoluminescence combined with an ultrafast photon set-up allowed us to see antibunching effect on excitons recombining in CdTe/ZnTe QD, as well within the biexciton ($X_{2}$)-exciton ($X$) radiative cascade from same dot. Fast microchannel plate photomultipliers time-correlated module gave...

We report the growth of ZnSe nanowires and nanoneedles using molecular beam epitaxy (MBE). Different regimes were found, depending on temperature Zn–Se flux ratio. By employing a combined MBE without any postprocessing sample, we achieved an efficient suppression stacking fault defects. This is confirmed by transmission electron microscopy photoluminescence studies.

Gold-catalyzed ZnTe nanowires were grown at low temperature by molecular beam epitaxy on a ZnTe(111) B buffer layer, under different II/VI flux ratios, including with CdTe insertions. High-resolution electron microscopy and energy-dispersive X-ray spectroscopy (EDX) gave information about the crystal structure, polarity, growth mechanisms. We observe, stoichiometric conditions, simultaneous presence of zinc-blende wurtzite spread homogeneously same sample. Wurtzite are cylinder-shaped...

We report on a novel GaAs:Si/(AlGa)As multiquantum well photodetector structure which exhibits photoresponse maxima in both the 8–12 and 3–5 μm spectral regions. The relative intensity of these strongly depends bias voltage, demonstrating potential such as tunable two-color intersubband detector.

We demonstrate theoretically and experimentally that four-wave mixing processes obey phase-matching conditions determine not only the conservation of photon energy k-momentum but also orbital angular momentum light. report on time-resolved experiments performed a CdTe/CdZnTe quantum well in both noncollinear collinear configurations with Laguerre-Gauss beams. They polarization wave which is induced material keeps memory excitation pulse momentum. show configuration, large acceptance opens up...

Optically active gold-catalyzed ZnTe nanowires have been grown by molecular beam epitaxy, on a ZnTe(111) buffer layer, at low temperature (350 °C) under Te rich conditions, and ultra-low density (from 1 to 5 per μm2). The crystalline structure is zinc blende as identified transmission electron microscopy. All are tapered the majority of them ⟨111⟩ oriented. Low micro-photoluminescence cathodoluminescence experiments performed single nanowires. We observe narrow emission line with blue-shift...

A series of n-type doped InAs bulk crystals has been studied by Fourier-transform photoluminescence in combination with excitation (FTPLE) spectroscopy. The FTPLE spectra exhibit a pronounced enhancement the oscillator strength at optical band gap even under degenerate doping conditions where significant Burstein-Moss shift is observed. spectral position observed changes same way as Fermi level increasing concentration. data are consistently explained Mahan's theory interband transitions...