scholarly journals Temperature Activated Dimensionality Crossover in the Nucleation of Quantum Dots by Droplet Epitaxy on GaAs(111)A Vicinal Substrates

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Artur Tuktamyshev ◽  
Alexey Fedorov ◽  
Sergio Bietti ◽  
Shiro Tsukamoto ◽  
Stefano Sanguinetti
Keyword(s):  
Quantum Dots ◽  
Low Temperature ◽  
Droplet Epitaxy ◽  
One Dimension ◽  
Finite Width ◽  
Two Dimensional ◽  
Droplet Nucleation ◽  
Adatom Diffusion ◽  
Dimensional Diffusion ◽  
Droplet Density

Abstract A temperature activated crossover between two nucleation regimes is observed in the behavior of Ga droplet nucleation on vicinal GaAs(111)A substrates with a miscut of 2° towards $$(\bar{1}\bar{1}2)$$ ( 1 ¯ 1 ¯ 2 ) . At low temperature (<400 °C) the droplet density dependence on temperature and flux is compatible with droplet nucleation by two-dimensional diffusion. Increasing the temperature, a different regime is observed, whose scaling behavior is compatible with a reduction of the dimensionality of the nucleation regime from two to one dimension. We attribute such behavior to a presence of finite width terraces and a sizeable Ehrlich-Schwöbel barrier at the terrace edge, which hinders adatom diffusion in the direction perpendicular to the steps.

Fabrication of Self-Assembled GaAs/AlGaAs Quantum Dots by Low-Temperature Droplet Epitaxy

1998 ◽  
Vol 37 (Part 1, No. 12B) ◽  
pp. 7158-7160 ◽  
Author(s):  
Chae-Deok Lee ◽  
Chanro Park ◽  
Hwack Joo Lee ◽  
Kyu-Seok Lee ◽  
Seong-Ju Park ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Temperature ◽  
Droplet Epitaxy ◽  
Self Assembled

scholarly journals Low-temperature scanning tunneling microscopy of selfassembled inas quantum dots grown by droplet epitaxy

2010 ◽  
Vol 3 (2) ◽  
pp. 1299-1304
Author(s):  
C. Durand ◽  
A. Peilloux ◽  
K. Suzuki ◽  
K. Kanisawa ◽  
B. Grandidier ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Temperature ◽  
Scanning Tunneling Microscopy ◽  
Droplet Epitaxy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Inas Quantum Dots ◽  
Temperature Scanning

scholarly journals Concentric GaAs nanorings growth modelling

2018 ◽  
Vol 52 (5) ◽  
pp. 520
Author(s):  
A.G. Nastovjak ◽  
I.G. Neizvestny ◽  
M.A. Vasilenko ◽  
N.L. Shwartz
Keyword(s):  
Monte Carlo Simulation ◽  
Diffusion Length ◽  
Three Dimensional ◽  
Droplet Epitaxy ◽  
Two Dimensional ◽  
Growth Modelling ◽  
Growth Morphology ◽  
Double Ring ◽  
Droplet Density ◽  
Numerical Approaches

AbstractThe nanostructures formation process using the droplet epitaxy technique was investigated by Monte Carlo simulation. The simulation was fulfilled for two-dimensional and three-dimensional geometry substrates. The nanostructures morphology dependence on the growth temperature was presented. Crystal clusters, single and double rings were observed. The nanostructures shape was shown to be determined by the gallium diffusion length. The conditions of double rings formation during the droplet epitaxy were considered using analytical and numerical approaches. The factors that determine the rings location and shape were analyzed. The growth morphology was demonstrated to be dependent on the initial distance L between the droplets. The double ring formation was possible at a low droplet density only, when the As-stabilized region could be created between the droplets.

Quantitative Diameter Measurements of Chromatin and TMV Fibers in the Freeze-Dried State

1988 ◽  
Vol 46 ◽  
pp. 170-171
Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore
Keyword(s):  
Reliable Method ◽  
Fiber Diameter ◽  
Quantitative Agreement ◽  
One Dimension ◽  
Fiber Axis ◽  
Two Dimensional ◽  
Fiber Density ◽  
Variable Diameter ◽  
Freeze Dried ◽  
Expected Values

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure

Annealing-Induced Structural Evolution of InAs Quantum Dots on InP (111)A Formed by Droplet Epitaxy

2021 ◽  
Author(s):  
Takaaki Mano ◽  
Akihiro Ohtake ◽  
Neul Ha ◽  
Takeshi Noda ◽  
Yoshiki Sakuma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Structural Evolution ◽  
Droplet Epitaxy ◽  
Inas Quantum Dots

Electrochemiluminescent chiral discrimination with chiral Ag2S quantum dots/few-layer carbon nitride nanosheets

The Analyst ◽  
2021 ◽  
Author(s):  
Qianqian Zhao ◽  
Wenrong Cai ◽  
Bao-Zhu Yang ◽  
Zhengzhi Yin ◽  
Datong Wu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nitride ◽  
Chiral Discrimination ◽  
Chiral Ligand ◽  
Two Dimensional ◽  
Ag2s Quantum Dots ◽  
Carbon Nitride Nanosheets

Well dispersed chiral Ag2S quantum dots (Ag2S QDs) were facilely synthesized by using N-acetyl-L-cysteine (NALC) as the chiral ligand, which were loaded onto the nanosheets of two-dimensional (2D) few-layer carbon...

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