Top Research Papers on Quantum Dots

Aspect of the present invention provides a method for producing such a quantum dot, a plurality of quantum dots.

Materials Science A wide range of materials can now be synthesized into semiconducting quantum dots. Because these materials grow from solutions, there is scope to combine quantum dots into devices by using simple, low-cost manufacturing processes. Kagan et al. review recent progress in tailoring and combining quantum dots to build electronic and optoelectronic devices. Because it is possible to tune the size, shape, and connectivity of each of the quantum dots, there is potential for fabricating electronic materials with properties that are not available in traditional bulk semiconductors. S...

Quantum dot is the important part of nanometre science and technology,quantum dot devices is one of development directions of nanometre devices.The classification,major method of preparation of quantum dot are introduced.Study on characteristic of quantum dot,the appalication of quantum dot devices and noise suppression are discussed.

A structure comprising a quantum dot is obtained by the method according to one of claims 1-6, wherein the quantumdot includes a layer of amphiphilic polymer disposed on the surface the quantum dot.

Embodiments of the invention provide such a manufacturing method, the quantum dot of the quantum dot.

FIELD: nanotechnology. SUBSTANCE: invention relates to nanotechnology. The method for production of a quantum dot comprises the following steps: a) mixing an amphiphilic polymer dissolved in a non-coordinating solvent with a first precursor for obtaining a carboxylate precursor; b) mixing the carboxylate precursor with the second precursor to obtain the quantum dot core; c) mixing the quantum dot core with the precursor selected from the group consisting of: a third precursor, a fourth precursor and their combination to obtain a coating of the quantum dot on the quantum dot core to form the qu...

To obtain the quantum dot having a novel structure. The method of manufacturing a quantum dot, in a solvent in the step of dispersing the nano oxide particles are exposed to the predetermined crystal plane in the solvent, the crystal plane of the nanosheet particles, a step of growing a semiconductor layer.

It discloses an X-ray imaging apparatus comprising X-ray detector, and it has impact resistance. X-ray photographing apparatus includes an X-ray detector is provided for detecting an irradiated X-rays from the x-ray source and the X-ray source for irradiating to generate the X-rays, and the x-ray detector comprises a case having at least one opening, the X-ray irradiation from the X-ray source to a frame which is removably inserted in the interior of the case is provided to convert an electrical signal sensing panel, through the at least one opening, the frame the X-rays from the edge of the b...

The invention discloses quantum dots modified by a macromolecular monomer. According to the quantum dots, the macromolecular monomer which is prepared through catalytic chain transfer polymerization is taken as a ligand; and the quantum dots have the characteristics of narrower fluorescence emission spectrum, high luminous efficiency and high stability. Particle sizes of the quantum dots modified by the macromolecular monomer are 2 to 20nm, the quantum dots are water-soluble, the quantum yield is 20 to 95 percent, the half-peak width of a photoluminescence spectrum is 20 to 80nm, and the fluor...

It is demonstrated that a comprehensive study of energy transfer between quantum dot pairs on the biotemplate and, alternatively, between quantum dots and molecular dyes embedded in the microtubule scaffold comprises a powerful spectroscopic tool for evaluating the assembly process.

The main goal of our work is the development of new nanomaterials based on fluorescent semiconducting nanoparticles (quantum dots). In our work a range of various cadmium selenide and ternary core cadmium zinc selenide quantum structures have been synthesised and investigated using spectroscopic techniques. Various quantum loaded polymer composite materials have been fabricated and tested. We expect that the new materials developed here will find many potential

Quantum dot nanostructures were investigated experimentally and theoretically for potential applications for optoelectronic devices. We have developed the foundation to produce state-of-the-art compound semiconductor nanostructures in a variety of materials: In(AsSb) on GaAs, GaSb on GaAs, and In(AsSb) on GaSb. These materials cover a range of energies from 1.2 to 0.7 eV. We have observed a surfactant effect in InAsSb nanostructure growth. Our theoretical efforts have developed techniques to look at the optical effects induced by many-body Coulombic interactions of carriers in active regions c...

The synthesis of glutathione-capped QDs is simple and cost-effective compared to the conventional organometallic approaches and can be easily scaled up for the commercial production of alloyed nanocrystals of various compositions.

The present invention discloses a kind of quantum dot synthesis means, comprising the precursor reaction zone sequentially connected, core / shell reaction zone and a storage container nuclear reaction zone, core / shell reaction, each reaction zone each comprise at least one spiral reaction tube, the above-described the reactor is provided with a helical spiral in opposite directions into the reaction tube due to friction reactant pathway groove bubble effect, the preceding reaction zone each covering a heating zone on the inner wall of the tube, each of the reaction zone after cooling zone c...

A micrometer-sized spherical microcavity, the photonic dot, is made from semiconductor nanocrystals, the quantum dots. The coupling of electronic and photonic states is demonstrated for a single photonic dot by the observation of whispering gallery modes in the spectrum of spontaneous emission of the embedded CdSe quantum dots.

Quantum dots (QDs) are a unique type of nanocrystalline semiconductor whose electronic and optical properties are dependent on the size and shape of the dots. Diameters of these particles can range from about 2-10 nm, on the order of 10-50 atomic lengths6. The small size of the particle gives a high ratio of surface-to-volume, so their properties fall somewhere between that of individual molecules and bulk semiconductors Quantum dots can be single elements (such as silicon, germanium, etc.) or compounds (CdSe, CdS, etc.)6.

It is demonstrated that time-series flow cytometry measurement of quantum dot labeled U-2OS osteosarcoma cells can be used to model the fluorescence signal and distinguish it from autofluorescence by deconvolution, and both methods in combination should further improve quantitative cell tracking experiments by flow and image cytometry.

Quantum dots (QDs) are a unique type of nanocrystalline semiconductor whose electronic and optical properties are dependent on the size and shape of the dots. Diameters of these particles can range from about 2-10 nm, on the order of 10-50 atomic lengths6. The small size of the particle gives a high ratio of surface-to-volume, so their properties fall somewhere between that of individual molecules and bulk semiconductors Quantum dots can be single elements (such as silicon, germanium, etc.) or compounds (CdSe, CdS, etc.)6.

: We investigated the temperature-dependent photoluminescence spectroscopy of colloidal InZnP/ZnSe/ZnS (core/ shell/shell) quantum dots with varying ZnSe and ZnS shell thickness in the 278~363 K temperature range. Temperature-dependent photoluminescence of the InZnP-based quantum dot samples reveal red-shifting of the photoluminescence peaks, thermal quenching of photoluminescence, and broadening of bandwidth with increasing temperature. The degree of band-gap shifting and line broadening as a function of temperature is affected little by shell composition and thickness. However, the thermal q...

We study electronic structures of two-dimensional quantum dots in strong magnetic fields using mean-field density-functional theory and exact diagonalization. Our numerically accurate mean-field solutions show a reconstruction of the uniform-density electron droplet when the magnetic field flux quanta enter one by one the dot in stronger fields. These quanta correspond to repelling vortices forming polygonal clusters inside the dot. We find similar structures in the exact treatment of the problem by constructing a conditional operator for the analysis.We discuss important differences and limitations ...

We propose an implementation of a universal set of one- and two-quantum-bit gates for quantum computation using the spin states of coupled single-electron quantum dots. Desired operations are effected by the gating of the tunneling barrier between neighboring dots. Several measures of the gate quality are computed within a recently derived spin master equation incorporating decoherence caused by a prototypical magnetic environment. Dot-array experiments that would provide an initial demonstration of the desired nonequilibrium spin dynamics are proposed.

1. Quantum chaos and billiards 2. Quantum transport and chaos in billiards 3. Motion of a billiard ball 4. Semiclassical theory of conductance fluctuations 5. Semiclassical quantization and thermodynamics of mesoscopic systems 6. Orbital diamagnetism and persistent current 7. Quantum interference in single open billiards 8. Linear response theory in semiclassical regime 9. Orbital bifurcations, Arnold diffusion and Coulomb blockade 10. Nonadiabatic transition, energy diffusion and generalized friction

I present recent advances and future prospects for self-assembled quantum dots for quantum information applications.

A review on the work aimed at experimental demonstration of Pauli blocking and single-spin measurement in single-electron-charged self-assembled quantum dots is presented.

The application of the spin of the electron confined in the quantum dot to read/write operations of quantum bits (qubits) and the realization of quantum logic gates is studied for the spin states of the two-electron system confined inThe two coupled quantum dots.

Experimental results were predicted by several recent theoretical models of motor learning, and should help to understand more about motor learning and motor control.

Charge-Kondo quantum dots have recently emerged as a new nanoelectronics paradigm. A pseudospin qubit is implemented with quasidegenerate macroscopic charge states of a large semiconductor dot, connected to two or more leads via quantum point contacts. Such devices offer unprecedented control over quantum effects and strongly correlated electron physics on the nanoscale. Here I show that charge-Kondo quantum dot devices are essentially perfect quantum simulators of nontrivial quantum impurity models, with Majorana-mediated quantum critical transport in two-channel charge-Kondo experiments agre...

This paper presents what the researchers have discovered for three types of systems: exciton systems, electron spin systems, and nuclear spin systems and investigates the role that polarons play in the decoherence of spin systems.

A method for manufacturing a quantum dot device includes the steps of: forming a first quantum dot solution with a plurality of quantum dots dispersed in a mixture solvent of a solvent and an anti-solvent; and forming a first quantum dot layer by natural evaporation after the first quantum dot solution is poured into a substrate structure. [Reference numerals] (S1) Step for preparing a substrate structure; (S2) Form a quantum dot solution with a plurality of quantum dots dispersed in a mixture solvent of a solvent and an anti-solvent;; (S3) Step for natural evaporation after the quantum dot so...

There is increasing interest in the potential application of quantum dots and quantum wires to various solid state devices. Applications include enhancing the performance of existing devices (e.g., semiconductor lasers based on quantum dot active layers), the creation of materials with exotic optical nonlinearities, the development of novel processor architectures based on cellular automata, and new concepts concerning the generation of synthetic dopants. In the quantum well hierarchy that has emerged over the last decade (i.e., quantum wells, wires and dots), quantum dots are the extreme quas...

Propose a implementation of a universal set of one-and two-qubit gates for quantum computation using the spin states of coupled single-electron quantum dots. Superoperator of the gate quality are computed within a newly derived spin master equation incorporating decoherence in the Born and Markov approximation.

729 Quantum Dots for Quantum Logic Although several technologies are being pursued for coherent quantum information processing, solid-state systems may prove the simplest to implement on a wide scale. Li et al. (p. 809) demonstrate a conditional quantum logic gate in which two qubits, each consisting of an exciton (an electron-hole pair), are coupled together in a single quantum dot. These qubits can be manipulated coherently with polarized light and can perform logical operations with a fidelity of 0.7.

As understanding of the degradation mechanisms of QDs increases and more stable QDs and display devices are developed, QDs are expected to play critical roles in advanced display applications.

To design nanocrystalline nanosystems, a theory for nanocrystals is needed which can be applied to nanocrystals with atomic-scale variations in composition, structure and shape. We present an empirical tight-binding theory for nanocrystal heteronanostructures. Electronic structure and optical absorption spectra are obtained for CdS/HgS/CdS and ZnS/CdS/ZnS quantum-dot quantum-well nanocrystals. Comparison with experiment shows that tight-binding theory provides a good description of nanosystems with monolayer variations in composition. Issues for designing nanocrystal heteronanostructures are d...

In an experiment on quantum mirages, confinement of surface states in an elliptical corral has been used to project the Kondo effect from one focus where a magnetic impurity was placed to the other, empty, focus. The signature of the Kondo effect is seen as a Fano antiresonance in scanning tunnelling spectroscopy. This experiment combines the many-body physics of the Kondo effect with the subtle effects of confinement. In this work we review the essential physics of the quantum mirage experiment, and present new calculations involving other geometries and more than one impurity in the corral, ...

We review recent theoretical work on the manipulation of single molecules with scanning probes, in particular the scanning tunnelling microscope (STM). The aim of theories and simulations is to account for the processes, ideally at a quantitative level, that permit the controlled manipulation of matter at the atomic scale in adsorbed molecular systems. In order to achieve this, simulations rely on total energy and electronic structure calculations where a trade-off is made between the size of the system and the accuracy of the calculation. This first stage of the calculation yields the basic q...

In a quantum dot, the electrons are confined in all three dimensions to a length scale of the order of the electron Fermi wavelength. Due to the confinement, quantum effects will dominate over the bulk properties and the energy spectrum becomes discrete, similar to that of an atom. In this review, we present a short introduction to electron confinement in nanosize structures and properties related to quantum size effects. Furthermore, we present a model for calculation of the electronic structure of adsorbed quantum dots, where we have focused on the system of Na on Cu(111). Our results are co...

We present calculations for the electronic and magnetic properties of surface states confined by a circular quantum corral built of magnetic adatoms (Fe) on a Cu(111) surface. We show the oscillations of charge and magnetization densities within the corral and the possibility of the appearance of spin-polarized states. In order to classify the peaks in the calculated density of states with orbital quantum numbers we analysed the problem in terms of a simple quantum mechanical circular well model. This model is also used to estimate the behaviour of the magnetization and energy with respect to ...

The invention discloses a quantum dot synthesis device. The device comprises a precursor reaction area, a core reaction area, a core/shell reaction area for a core/shell reaction, and a storage container which are sequentially connected, each of above reaction areas includes at least one spiral reaction tube, the inner wall of every spiral reaction tube is provided with a passing groove having a direction opposite to the spiral direction and allowing reactants injected into the reaction tube to generate a bubbling effect due to friction, the front segment of every reaction area is coated with ...

The growth and characterization of two types of self-organized quantum dots, Stranski-Krastanow (S-K) mode grown quantum dots and atomic layer epitaxy (ALE) grown quantum dots, are described. In the S-K mode growth, molecular beam epitaxy has been used. Multilayer stacked structures have been fabricated. S-K mode grown quantum dots showed the ground state photoluminescence (PL) emission wavelength of 1.14 μm and the full width at half maximum of the emission linewidth of 80 meV. ALE mode grown quantum dots are fabricated using metalorganic chemical vapor deposition. A smaller PL linewidth of 4...

The invention discloses a method for gluing quantum dot films and the quantum dot films. The method comprises the steps of preparing one or more layers of quantum dot films from colloidal quantum dots, volatilizing solvents in the quantum dot films after the films are formed, and forming the quantum dot films which only contain the quantum dots; putting the quantum dot films into a vacuum plasma generation cavity; and introducing H2 into the vacuum plasma generation cavity, then transforming the H2 into H plasma and gluing the quantum dot films through the H plasma. The quantum dot films are g...

The self-assembling growth process during the highly-strained semiconductor epitaxy has allowed high-quality quantum dots applicable to optical devices to be formed. This talk provides the following topics on our research of self-assembled InGaAs quantum dots and quantum-dot lasers: 1) growth of self-assembled quantum dots, 2) laser performance of our originally-designed columnar-shaped quantum-dot lasers, 3) influence of homogeneous broadening of optical gain on lasing spectra, 4) origin of temperature characteristic of threshold currents, and 5) recent progress in the quantum-dot crystal gro...

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 molecules are described and calibrated using numerical simulations. It is shown how these models can be used to design optimized quantum-dot molecules for quantum coherence applications. The wave functions and energies obtained from the optimizations are used as input for a microscopic calculation of the quantum-dot material dynamics including carrier scatte...

This work presents the theory of exciton coupling to photons and longitudinal optical (LO) phonons in quantum dots (QDs) and quantum-dot molecules (QDMs). Resonant-round trips of the exciton between the ground (bright) and excited (dark or bright) states, mediated by the LO phonon, alter the decay time and yield the Rabi oscillation. The initial distributions of the population in the ground and the excited states dominate the oscillating amplitude and frequency. This property provides a detectable signature to the information that is stored in a qubit that is made from QD or QDM, over a wide r...

Introduction The advanced growth of semiconductor quantum dots (QDs) with high optical quality is one key to realizing novel devices in various research disciplines related to modern semiconductor technologies. Despite recent progress in the top-down lithographic fabrication of single semiconductor QD-like emitters [43], bottom-up fabrication methods are commonly applied for the realization of high quality light emitting QDs [7]. The exploitation of high-density QD arrays as an active material in laser diodes [17] and vertical cavity surface emitting lasers (VCSEL) resulted in a new class of d...

An online platform for simulating quantum dots has been shown and will include ability to simulate random alloys and ability to import disordered structures and calculate energy levels for such disordered systems in the future.

It provides a semiconductor structure comprising a quantum dot and a quantum dot method. QD manufacturing method comprising: preparing a (a) a first barrier layer, the well layer and the compound semiconductor layer 2, the barrier layer comprises a quantum well structure are sequentially stacked; (B), but forming a dielectric thin film pattern including the second barrier layer onto the said first coefficient of thermal expansion is greater than the second barrier layer, the first dielectric thin film, and wherein the small second dielectric thin-film coefficient of thermal expansion than the ...

The invention discloses a quantum dot electroluminescent unit and a quantum dot electroluminescent device. The quantum dot electroluminescent unit comprises multiple electrophosphorescent quantum dots and at least one organic electroluminescent material, wherein the electrophosphorescent quantum dots are dispersed in the organic electroluminescent material; the organic electroluminescent material has a structure in the following formula (1) as described in the specifications, one or two of R1 to R5 is/are independent triazole derivative(s), the triazole derivative has a structure in the follow...

The invention discloses a quantum dot light source and a quantum dot backlight module. The quantum dot light source comprises a light bar and a quantum dot film. The light bar comprises a circuit board and a plurality of light emitting diodes. A plurality of containing cavities are formed in one outer side face of the circuit board in a sunken mode and are used for placing containing the light emitting diodes, and the light emitting diodes do not exceed the outer side face of the circuit board. The quantum dot film covers the containing cavities of the circuit board. The quantum dot light sour...

We discuss the observation of an unusual type of localization in split-gate quantum dots and quantum-dot arrays. While no evidence for its existence is found prior to biasing the gates, the localization persists to conductance values as high as 50 e/h and is not destroyed by the application of a weak magnetic field. The carrier density in the dots remains constant over the range of gate bias studied and these characteristics suggest that the localization is quite distinct to that studied previously in two-dimensional semiconductors. We suggest that a confinement-induced enhancement of the elec...