scholarly journals Preparation and Characterization of Self-Assembled Thin Film of MPS-Capped ZnS Quantum Dots for Optical Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Kenan Koç ◽  
Fatma Z. Tepehan ◽  
Galip G. Tepehan
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Optical Filter ◽  
Refractive Indices ◽  
Glass Substrates ◽  
Heat Treated ◽  
Dielectric Coefficient ◽  
Self Assembled ◽  
Optical Applications

For this study, we prepared colloidal ZnS quantum dots using 3-mercaptopropyltrimethoxysilane (MPS) as the capping agent. Colloidal ZnS quantum dots were directly deposited on glass substrates by a spin coating process. Therefore, self-assembled films made of ZnS quantum dots in a SiO2network were obtained using only one production step. The films were heat-treated at 100°, 125°, 150°, 175° and 200°C in an N2atmosphere. The results showed that the dimension of quantum dots changed from 2.8 nm to 3.2 nm by heat treatment. The refractive index, extinction coefficient, thickness, and dielectric coefficient values of the films were calculated. The present study showed that size and the refractive indices of films can be controlled by the heat treatment. Therefore, such films can be a good candidate in optical filter applications.

Deep level transient spectroscopy characterization of InAs self-assembled quantum dots

2001 ◽  
Vol 89 (2) ◽  
pp. 1172-1174 ◽  
Author(s):  
V. V. Ilchenko ◽  
S. D. Lin ◽  
C. P. Lee ◽  
O. V. Tretyak
Keyword(s):  
Quantum Dots ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Self Assembled ◽  
Transient Spectroscopy

Characterization of Ultrafine Glassy Powder for Al-Si-Ca-P-O-F Polynary System by Liquid Precipitation

2010 ◽  
Vol 177 ◽  
pp. 433-436 ◽  
Author(s):  
G.C. Yuan ◽  
Q.G. Wu ◽  
Guo Xun Zeng ◽  
Z.Y. Ling
Keyword(s):  
Heat Treatment ◽  
Network Structure ◽  
Inorganic Compounds ◽  
Amorphous State ◽  
Precipitation Method ◽  
Hollow Particles ◽  
Heat Treated ◽  
Quenched Glass ◽  
Liquid Precipitation

The ultrafine glassy powder of Al-Si-Ca-P-O-F polynary system was prepared by liquid precipitation method with several inorganic compounds as reactants containing the ions such as Al3+, SiO32-, P3O105-, Ca2+, F-, respectively. The powder was heat-treated in the range of temperature from 773 to 1173K and its crystallized processes were ascertained. The morphology, composition, bonding state and structure, crystallized behavior of the glassy powder were characterized by means of TEM, XRD, EDAX, IR, DSC etc methods. The results show that the powder containing Al, Si, Ca, P, O, F elements belongs to typical amorphous state, and the particles appeared hollow and near spherical morphology with the size from 30 to 70nm. The hollow particles collapsed as plate like conglutination state and a series of crystallized phases CaF2, Al2SiO5, Ca2SiO4, and Ca3(PO4)2 were separated sequentially during heat treatment in the range of temperature above. The characteristics of the glassy powder are similar to those of popular melting-quenched glass of the system. The network structure of the glass was mainly formed by the tetrahedrons of [SiO4], [AlO4] and [PO4], which were linked by the oxygen atoms of the angle in the tetrahedrons.

Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

2018 ◽  
Vol 275 ◽  
pp. 81-88
Author(s):  
Monika Karoń ◽  
Marcin Adamiak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Internal Stresses ◽  
Refined Grains ◽  
Angular Pressing ◽  
Heat Treated ◽  
Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

scholarly journals Photoreflectance characterization of InAs/GaAs self-assembled quantum dots grown by ALMBE

2000 ◽  
Vol 16 (1) ◽  
pp. 19-24 ◽  
Author(s):  
M. Geddo ◽  
R. Ferrini ◽  
G. Guizzetti ◽  
M. Patrini ◽  
S. Franchi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Self Assembled

Characterization of Self-Assembled CdTe Quantum Dots Grown on ZnTe/GaSb

2012 ◽  
Vol 18 (S2) ◽  
pp. 1438-1439
Author(s):  
D. Tang
Keyword(s):  
Quantum Dots ◽  
Cdte Quantum Dots ◽  
Self Assembled

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Mechanical Properties of Sol-Gel Inorganic-Organic Hybrid Films in Nanoindentation

2006 ◽  
Vol 317-318 ◽  
pp. 317-322 ◽  
Author(s):  
J.Q. Zhang ◽  
Atsunori Matsuda ◽  
Hiroyuki Muto ◽  
Mototsugu Sakai
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Time ◽  
Sol Gel ◽  
Heat Treatment Time ◽  
Nanoindentation Test ◽  
Glass Substrates ◽  
Organic Hybrid ◽  
Elastoplastic Properties ◽  
Heat Treated

Methylsilsesquioxane films were formed on glass substrates by dropping a sol prepared from methyltriethoxysilane and then heat-treated in an oven. Nanoindentation test was performed to assess the elastoplastic properties of the films, including the relative residual depth ξr, Meyer hardness HM, work-of-indentation WI and the elastic modulus E’. The values of ξr, HM and WI were obtained by a Berkovich indenter and E’ was determined by a spherical indenter on the basis of Hertz elastic theory. ξr decreased with the increase in the heat treatment time, whereas HM , WI and E’ significantly increased with the time. The changes in the mechanical properties with the heat treatment time well reflected the evolution of the Si-O-Si network structure in methylsilsequioxane film.

scholarly journals Self Assembly of semiconductor nanostructures

Respuestas ◽  
2016 ◽  
Vol 12 (2) ◽  
pp. 47-51
Author(s):  
Máximo López-López ◽  
Esteban Cruz-Hernández ◽  
Isaac Martínez-Velis ◽  
Juan Salvador Rojas-Ramírez ◽  
Manolo Ramirez-Lopez ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Self Assembly ◽  
Molecular Beam ◽  
Quantum Wires ◽  
Preferential Growth ◽  
Growth Method ◽  
Strong Surface ◽  
Self Assembled

 Abstract In this work we present the growth and characterization of GaAs self-assembled quantum wires (SAQWRs), and InAs self-assembled quantum dots (SAQDs) by molecular beam epitaxy on (631)-oriented GaAs substrates. Adatoms on the (631) crystal plane present a strong surface diffusion anisotropy which we use to induce preferential growth along one direction to produce SAQWRs. On the other hand, InAs SAQDs were obtained on GaAs(631) with SAQWRs by the Stransky–Krastanov (S-K) growth method. SAQDs grown directly on (631) substrates presented considerable fluctuations in size. We study the effects of growing a stressor layer before the SAQDs formation to reduce these fluctuations.Keywords : Quantum wires, quantum dots; selfassembly; molecular beam epitaxy.

scholarly journals Hydrogen Detection with SAW Polymer/Quantum Dots Sensitive Films

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4481 ◽  
Author(s):  
Izabela Constantinoiu ◽  
Cristian Viespe
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Room Temperature ◽  
Limit Of Detection ◽  
Composite Films ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Gas Molecules

Regarding the use of hydrogen as a fuel, it is necessary to measure its concentration in air at room temperature. In this paper, sensitive composite films have been developed for surface acoustic wave (SAW) sensors, using quantum dots (QDs) and polymers. Si/SiO2 QDs were used due to having a high specific surface area, which considerably improves the sensitivity of the sensors compared to those that only have a polymer. Si/SiO2 QDs were obtained by laser ablation and analyzed by X-ray diffraction and transmission electron microscopy (TEM). Two types of polymers were used: polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA). Polymer and polymer with QDs compositions were deposited on the sensor substrate by drop casting. A heat treatment was performed on the films at 80 °C with a thermal dwell of two hours. The sensors obtained were tested at different hydrogen concentrations at room temperature. A limit of detection (LOD) of 452 ppm was obtained by the sensor with PDMS and Si/SiO2 QDs, which was heat treated. The results demonstrated the potential of using QDs to improve the sensitivity of the SAW sensors and to achieve a heat treatment that increases its adsorption capacity of the gas molecules.

Growth and characterization of MgS/CdSe self-assembled quantum dots

2003 ◽  
Vol 251 (1-4) ◽  
pp. 581-585 ◽  
Author(s):  
C. Bradford ◽  
B. Urbaszek ◽  
M. Funato ◽  
A. Balocchi ◽  
T.C.M. Graham ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Self Assembled
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