Top Research Papers on 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.

In a THz pump - optical probe experiment we demonstrate an instantaneous electro-absorption effect in InGaAs/GaAs quantum dots, induced by the electric field of a single-cycle THz pulse with 3 THz bandwidth and with free-space peak electric field reaching 220 kV/cm. The transient modulation of QD ground state optical absorption at 1040 nm coherently follows the evolution of the absolute value of THz electric field. The optical modulation signal was found to be as short as 460 fs at FWHM, and retained the 3 THz bandwidth of the THz pulse. Optical absorption modulation in QDs by the THz field is domi...

: 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 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...

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 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 ...

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.

A source of single photons that meets three important criteria for use in quantum-information systems has been unveiled in China by an international team of physicists. Based on a quantum dot, the device is an efficient source of photons that emerge as solo particles that are indistinguishable from each other. The researchers are now trying to use the source to create a quantum computer based on "boson sampling". [11]

The use of semiconductors has greatly increased in the last century. As new technologies start to re ly more and more on semi-conductors, their shortcomings are more and more apparent. Traditional semi-conductor devices have been found to be too big and too slow. As engineers search for a fa ster and more adaptable alternative to conventional semiconductors they have discovered quantum dots, a new form of semiconductors that model atoms. Being only nanometers in size, these pseudo-atoms take semi-conductors to a whole new level and can a llow devices to work almost at the speed of light. Furth...

A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atom s are, of course, quantum dots, but multi-molecular combinations can have this characteristic. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10 9 meter or a millionth of a millimeter. In this paper, we will discuss the quantum dot and their application. Copyright © 2016 IFSA Publishing, S. L.

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.

A source of single photons that meets three important criteria for use in quantum-information systems has been unveiled in China by an international team of physicists. Based on a quantum dot, the device is an efficient source of photons that emerge as solo particles that are indistinguishable from each other. The researchers are now trying to use the source to create a quantum computer based on "boson sampling". [11]

In this paper, paints, an optoelectronic materials were used to make better photovoltaic cells, imaging sensors, and optical communication equipment by considering the nanomaterial design understanding at a molecular level. Infrared solar cells from semiconductor quantum dots were developed and the paint-on technology for other device applications were also discussed.

Modern electronics is being transformed as device size decreases to a size where the dimensions are significantly smaller than the constituent electron's mean free path. In such systems the electron motion is strongly confined resulting in dramatic changes of behaviour compared to the bulk. This book introduces the physics and applications of transport in such mesoscopic and nanoscale electronic systems and devices. The behaviour of these novel devices is influenced by numerous effects not seen in bulk semiconductors, such as the Aharonov–Bohm Effect, disorder and localization, energy quantiza...

This Special Issue provides detailed guides for synthesis of high-quality QDs and their applications and addresses issues to be addressed in fabricating devices, tailoring optical properties of QDs, and engineering defects in QD-related interfaces for higher performance.

Abstract : Much of the progress in solid-state microelectronics has come from the continued reduction in size of the transistors that make up integrated circuits (ICs), having dropped by a factor of 10 in the last decade to where minimum device geometries have reached approximately 350 nanometers in mass production. Continued improvements in ICs will require a device technology that can be scaled down to the sub-100 nanometer size regime. There, the quantum mechanical nature of the electron becomes strongly evident, and new design tools are required for a nano-electronic semiconductor technolo...

We consider quantum dots with a parabolic confining potential. The qualitative features of such mesoscopic systems as functions of the total number of electrons N and their total angular momentum J, e.g. magic numbers, overall symmetries etc., are derived solely from combinatoric principles. The key is one simple hypothesis about such quantum dots yielding a basis of states (different from the usual single electron states one starts with) which is extremely easy to handle. Within this basis all qualitative features are already present without the need of any perturbation theory.

Quantum dots (QDs) are very small nanoparticles and are composed of hundreds to thousands of atoms. These semiconducting materials can be made from an element, such as silicon or germanium, or compounds such as cadmium sulphide (CdS) or cadmium selenide (CdSe). The colour of these small particles does not depend on the type of semiconducting material from which the dots are made, but rather on its diameter. Besides, ODs attract the most attention because of their unique visual properties. Therefore, these are used in all kinds of applications where precise control of coloured light is importan...

In 1980s, the discovery of synthesis processes for nanostructured materials and the demonstration of the highly reactive properties of these materials have increased rapidly. The new synthesis processes have made available nanostructured materials in a wide variety of compositions, which have led to their exceptional changes in chemical, electronic and optoelectronic properties [1-24] . Synthesis of quantum dots is of great importance as the size, shape and hence their properties extremely depend on preparation technique. There are many popular methods to synthesize [1-4]

Nitro derivatives are considered as major environmental pollutants and issues of health concern. In current times, a variety of methods and techniques have been utilized for the sensing of these nitro derivatives. In view of this, the remarkable fluorescence properties of quantum dots (QDs) provide a great opportunity to detect these nitro derivatives. This review highlighted the recent reports of QDs as the sensing material for these nitro derivative explosives. Different modifications in QDs using physical and chemical approaches can be used to improve their sensing output. Various interacti...