Lateral alloy segregation in thin heteroepitaxial films

2009 ◽  
Vol 79 (7) ◽  
Author(s):  
J. M. Reich ◽  
X. B. Niu ◽  
Y.-J. Lee ◽  
R. E. Caflisch ◽  
C. Ratsch
Keyword(s):  
Alloy Segregation

Alloy Segregation, Quantum Confinement, and Carrier Capture in Self-Ordered Pyramidal Quantum Wires

Nano Letters ◽  
2006 ◽  
Vol 6 (5) ◽  
pp. 1036-1041 ◽  
Author(s):  
Q. Zhu ◽  
E. Pelucchi ◽  
S. Dalessi ◽  
K. Leifer ◽  
M.-A. Dupertuis ◽  
...  
Keyword(s):  
Quantum Confinement ◽  
Quantum Wires ◽  
Carrier Capture ◽  
Alloy Segregation

Study of Diffusion Length and Alloy Segregation in MOCVD AlGaAs

1987 ◽  
Vol 102 ◽  
Author(s):  
J. L. Bradshaw ◽  
W. J. Choyke ◽  
Z. C. Feng ◽  
D. L. Meier ◽  
R. L. Messham
Keyword(s):  
Low Temperature ◽  
Diffusion Length ◽  
Electron Diffusion ◽  
Direct Excitation ◽  
Gaas Substrates ◽  
Electron Diffusion Length ◽  
Alloy Segregation ◽  
Low Temperature Photoluminescence

ABSTRACTVarious thicknesses of AlGaAs are grown on GaAs substrates by MOCVD. Low temperature photoluminescence of the substrate is observed even for layers of AlGaAs 24μm thick. Direct excitation by the 488.0 nm pumping radiation and excitation by reradiation from the AlGaAs are eliminated as causes. From photoluminescence and EBIC studies, evidence is given to show that the substrate luminescence is caused by a much larger than expected electron diffusion length. A small trace of GaAs luminescence may be due to alloy segregation in the AlGaAs films themselves.

Optimal Filling of Test Dies for Evaluating Properties of Semi-Solid Alloys

2006 ◽  
Vol 116-117 ◽  
pp. 145-148
Author(s):  
Chee Ang Loong ◽  
Chang Qing Zheng
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
A356 Alloy ◽  
Flow Patterns ◽  
Optical And Electron Microscopy ◽  
Semi Solid ◽  
The Moment ◽  
Alloy Segregation ◽  
Solid Alloys ◽  
Filling And Solidification

An investigative study was conducted on how two different dies designed to produce sound specimens for evaluating mechanical properties of semi-solid alloys could be filled optimally. The first die contains one cavity that produces a wedge with a sectional thickness varying from 19.05 mm (0.75 in) to 9.52 mm (0.375 in). The second die contains four cavities fed by a single runner, producing ASTM-type round bars with a diameter of 9.52 mm (0.375 in). Experiments were undertaken to cast partial and complete shots of A356 alloy test specimens under controlled injection conditions. Flow patterns developed from the moment the alloy entered the cavity were noted, including difficulties experienced in balancing flow in the four-cavity die. Microstructural abnormalities were observed in the bar specimens examined using optical and electron microscopy. It was found that control of filling and solidification in the wedge die was much easier and specimens produced did not result in any significant alloy segregation.

Adsorption of oxygen and carbon monoxide on DymCun bimetallic surfaces at room temperature

1987 ◽  
Vol 52 (10) ◽  
pp. 2392-2400
Author(s):  
Josef Kopešťanský
Keyword(s):  
Carbon Monoxide ◽  
Surface Layer ◽  
Room Temperature ◽  
Dipole Moments ◽  
Dissociative Adsorption ◽  
Copper Surfaces ◽  
Cu Content ◽  
Bimetallic Surfaces ◽  
Adsorbed Co ◽  
Alloy Segregation

The adsorption of oxygen and carbon monoxide on surfaces of dysprosium, copper, and their bimetallic “alloys” DymCun was studied by work function measurements. In the starting stage of adsorption of oxygen, copper surfaces are more reactive than dysprosium surfaces, and bulk oxide appears in the sub-surface copper layers at room temperature; this was also observed for the bimetallic surfaces, where the starting adsorption of oxygen took place nearly exclusively on copper. With dysprosium, the bulk oxide did not form at room temperature; instead, oxygen was adsorbed on the surface to form a layer consisting of species of two kinds with substantially different dipole moments. Carbon monoxide practically did not adsorb on copper at 25 °C, whereas on dysprosium it exhibited dissociative adsorption. On the bimetallic surfaces (DyCu and DyCu6) the amount of adsorbed CO decreased proportionally to the increasing Cu content of the alloy. Segregation of copper in the surface layer, observed for the bimetallic DymCun “alloys”, resulted in an additional decrease in the amount of adsorbed CO.

scholarly journals Alloy segregation at stacking faults in zincblende GaN heterostructures

2020 ◽  
Vol 128 (14) ◽  
pp. 145703
Author(s):  
B. Ding ◽  
M. Frentrup ◽  
S. M. Fairclough ◽  
M. J. Kappers ◽  
M. Jain ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Alloy Segregation

Development and Application of Aluminium-Lithium Alloy

2014 ◽  
Vol 599-601 ◽  
pp. 12-17 ◽  
Author(s):  
Cheng Lu Zou ◽  
Gui Hong Geng ◽  
Wei Ye Chen
Keyword(s):  
Simulated Microgravity ◽  
Lower Cost ◽  
Early Stage ◽  
Third Generation ◽  
Advantages And Disadvantages ◽  
The Third ◽  
Lithium Alloy ◽  
History Of ◽  
Alloy Segregation ◽  
Lithium Alloys

The history of aluminium-lithium alloys development has been reviewed in this paper. According to the strength, weld ability and corrosion resistance, thermal stability and plasticity, aluminium-lithium alloy has been categorized and the defects of aluminium-lithium alloys in early stage have been analyzed. As compared the third generation of aluminium-lithium alloy with normal aluminum alloy and composite materials, it indicates aluminium-lithium alloy has better performance, lower cost and reduced weight. After analyzing the advantages and disadvantages of the rapid solidification, ingot casting metallurgy and electromagnetic simulated microgravity methods in synthesis of aluminium-lithium alloy, it has been found microgravity method has prominent effect on reducing the alloy segregation and lithium losses. Finally, the future development of aluminium-lithium alloys has been discussed.

Sign in / Sign up

Export Citation Format

Share Document