scholarly journals Self-assembly of quantum dots and rings by droplet epitaxy and their optical properties

2009 ◽  
Vol 3 (1) ◽  
pp. 031605 ◽  
Author(s):  
Takashi Kuroda
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Self Assembly ◽  
Droplet Epitaxy

scholarly journals EXPERIMENTAL STUDY OF 3D SELF-ASSEMBLED PHOTONIC CRYSTALS AND COLLOIDAL CORE-SHELL SEMICONDUCTOR QUANTUM DOTS

2017 ◽  
Vol 24 (1&2) ◽  
pp. 161-170
Author(s):  
Pham Thu Nga ◽  
Vu Duc Chinh ◽  
Nguyen Xuan Nghia ◽  
Nguyen Viet Huy ◽  
Dao Nguyen Thuan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Quantum Dots ◽  
Optical Properties ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Self Assembly ◽  
Photonic Band Gap ◽  
Semiconductor Quantum Dots ◽  
Core Shell ◽  
Sphere Diameter

In this contribution we present an experimental study of 3D opal photonic crystals. The samples are opals constituted by colloidal silica spheres, realized with self-assembly technique. The sphere diameter is selected in order to obtain coupling of the photonic band gap with the emission from CdSe/ZnS colloidal quantum dots. The quantum dots infiltrated in the opals is expected to be enhanced or suppressed depending on the detection angle from the photonic crystal. The structural and optical characterization of the SiO2 opal photonic crystals are performed by field-emission scanning electron microscopy and reflectivity spectroscopy. Measurements performed on samples permits to put into evidence the influence of the different preparation methods on the optical properties. Study of self-activated luminescence of the pure opals is also presented. It is shown that the luminescence of the sample with QDs have original QD emission and not due to the photonic crystal structure. The optical properties of colloidal core-shell semiconductor quantum dots of CdSe/ZnS which are prepared in our lab will be mention.

Type-II GaSb/GaAs Nanostructures Grown by Droplet Epitaxy with Various Ga Amounts

2015 ◽  
Vol 1131 ◽  
pp. 60-63 ◽  
Author(s):  
Maetee Kunrugsa ◽  
Somsak Panyakeow ◽  
Somchai Ratanathammaphan
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Optical Properties ◽  
Droplet Epitaxy ◽  
Formation Mechanisms ◽  
Type Ii ◽  
Quantum Rings ◽  
Force Microscopy ◽  
Atomic Force

We study the GaSb/GaAs nanostructures (NSs) grown by droplet epitaxy technique with various Ga amounts. Ga amount deposited on the GaAs (001) substrate was varied between 3-5 ML to form the different size and density of liquid Ga droplets. The Sb flux was subsequently irradiated to crystallize the droplets. Morphology of GaSb NSs was investigated by atomic force microscopy (AFM). Quantum rings were obtained after crystallizing 3-ML Ga droplets, whereas some kind of quantum dots were formed after crystallizing 4-and 5-ML Ga droplets. The formation mechanisms leading to the different structure are discussed. The photoluminescence (PL) measurement was performed to examine the optical properties of GaSb/GaAs NSs.

The self-assembly synthesis of tungsten oxide quantum dots with enhanced optical properties

2015 ◽  
Vol 3 (14) ◽  
pp. 3280-3285 ◽  
Author(s):  
Songling Wang ◽  
Stephen V. Kershaw ◽  
Guisheng Li ◽  
Michael K. H. Leung
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Tungsten Oxide ◽  
Self Assembly ◽  
The Self ◽  
One Pot ◽  
Photoluminescence Emission ◽  
Microwave Assisted ◽  
Blue Photoluminescence

A one-pot microwave-assisted methodology was explored to fabricate ultrafine WO3 quantum dots, with excellent thermal/photonic stabilities favorable for blue photoluminescence emission and photochromic performance.

Growth Structure, and Optical Properties of III-Nitride Quantum Dots

2003 ◽  
Vol 799 ◽  
Author(s):  
Hadis Morkoç ◽  
Arup Neogi ◽  
Martin Kuball
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Self Assembly ◽  
Light Polarization ◽  
Electronic Density ◽  
Group Iv Semiconductor ◽  
Polarization Insensitive ◽  
Low Threshold ◽  
Laboratory Analogue ◽  
Physical Phenomena

ABSTRACTQuasi-zero-dimensional (0D) semiconductors have been the subject of considerable interest which is stemmed from their unique physical properties which in turn are conducive to devices such as low threshold lasers and light polarization insensitive detectors, in addition to exciting basic physical phenomena. A laboratory analogue of 0D systems is semiconductor quantum dots (QDs) wherein the electronic states are spatially localized and the energy is fully quantized, loosely similar to an atomic system, making it more stable against thermal perturbations. In addition, the electronic density of states near the band gap is higher than in 3D and 2D systems, leading to a higher probability for optical transitions. Furthermore, the electron localization may dramatically reduce the scattering of electrons by bulk defects and reduce the rate of non-radiative recombination. Semiconductor based and metal based dots have been produced, the former via self-assembly and also by lithographic methods in many II-VI, III-V, and group IV semiconductor. The aim of this paper is focused on III-Nitride based quantum dots covering their production and optical properties, as well as reporting on the GaN quantum dots produced by molecular beam epitaxy utilizing standard, ripening, metal spray followed by nitridation methods.

Self-assembly of Semiconductor Quantum Dots by Droplet Epitaxy

2006 ◽  
Vol 959 ◽  
Author(s):  
Nobuyuki Koguchi
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Substrate Surface ◽  
Molecular Beams ◽  
Droplet Epitaxy ◽  
Ring Shape ◽  
Direct Formation ◽  
Growth Method ◽  
Ring Structures ◽  
Column Element

ABSTRACTWe have proposed a novel self-assembling growth method, termed Droplet Epitaxy, for the direct formation of QDs without using any lithography in 1990. Compared with the island formation based on the Stranski-Krastanow growth mode, the Droplet Epitaxy is applicable to the formation of quantum dots not only in lattice-mismatched but also in lattice-matched systems such as GaAs/AlGaAs. The process of the Droplet Epitaxy in MBE chamber consists of forming numerous III-column element droplets such as Ga or InGa with homogeneous size of around 10 nm on the substrate surface first by supplying their molecular beams, and then reacting the droplets with As molecular beam to produce GaAs or InGaAs epitaxial microcrystals. Another advantage of the Droplet Epitaxy is the possibility of the fabrication of QDs structures without wetting layer by cotrolling the stoichiometry of the substrate surface just before the deposition of III-column element droplets. Also we can control the shape of the QDs structure self-organizingly such as pyramidal shape, single-ring shape and concentric double-ring shape. These ring structures will provide excellent possibilities for the investigation of quantum topological phenomena.

Growth Structure, and Optical Properties of III-Nitride Quantum Dots

2003 ◽  
Vol 789 ◽  
Author(s):  
Hadis Morkoç ◽  
Arup Neogi ◽  
Martin Kuball
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Self Assembly ◽  
Light Polarization ◽  
Electronic Density ◽  
Group Iv Semiconductor ◽  
Polarization Insensitive ◽  
Low Threshold ◽  
Laboratory Analogue ◽  
Physical Phenomena

ABSTRACTQuasi-zero-dimensional (0D) semiconductors have been the subject of considerable interest which is stemmed from their unique physical properties which in turn are conducive to devices such as low threshold lasers and light polarization insensitive detectors, in addition to exciting basic physical phenomena. A laboratory analogue of 0D systems is semiconductor quantum dots (QDs) wherein the electronic states are spatially localized and the energy is fully quantized, loosely similar to an atomic system, making it more stable against thermal perturbations. In addition, the electronic density of states near the band gap is higher than in 3D and 2D systems, leading to a higher probability for optical transitions. Furthermore, the electron localization may dramatically reduce the scattering of electrons by bulk defects and reduce the rate of non-radiative recombination. Semiconductor based and metal based dots have been produced, the former via self-assembly and also by lithographic methods in many II-VI, III-V, and group IV semiconductor. The aim of this paper is focused on III-Nitride based quantum dots covering their production and optical properties, as well as reporting on the GaN quantum dots produced by molecular beam epitaxy utilizing standard, ripening, metal spray followed by nitridation methods.

Growth Structure, and Optical Properties of III-Nitride Quantum Dots

2003 ◽  
Vol 794 ◽  
Author(s):  
Hadis Morkoç ◽  
Arup Neogi ◽  
Martin Kuball
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Self Assembly ◽  
Light Polarization ◽  
Electronic Density ◽  
Group Iv Semiconductor ◽  
Polarization Insensitive ◽  
Low Threshold ◽  
Laboratory Analogue ◽  
Physical Phenomena

ABSTRACTQuasi-zero-dimensional (0D) semiconductors have been the subject of considerable interest which is stemmed from their unique physical properties which in turn are conducive to devices such as low threshold lasers and light polarization insensitive detectors, in addition to exciting basic physical phenomena. A laboratory analogue of 0D systems is semiconductor quantum dots (QDs) wherein the electronic states are spatially localized and the energy is fully quantized, loosely similar to an atomic system, making it more stable against thermal perturbations. In addition, the electronic density of states near the band gap is higher than in 3D and 2D systems, leading to a higher probability for optical transitions. Furthermore, the electron localization may dramatically reduce the scattering of electrons by bulk defects and reduce the rate of non-radiative recombination. Semiconductor based and metal based dots have been produced, the former via self-assembly and also by lithographic methods in many II-VI, III-V, and group IV semiconductor. The aim of this paper is focused on III-Nitride based quantum dots covering their production and optical properties, as well as reporting on the GaN quantum dots produced by molecular beam epitaxy utilizing standard, ripening, metal spray followed by nitridation methods.

Optical properties of GaSb/GaAs type-ІІ quantum dots grown by droplet epitaxy

2009 ◽  
Vol 94 (8) ◽  
pp. 081911 ◽  
Author(s):  
Takuya Kawazu ◽  
Takaaki Mano ◽  
Takeshi Noda ◽  
Hiroyuki Sakaki
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Droplet Epitaxy
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