Low Temperature Growth Mechanisms for Rheed Oscillations

1993 ◽  
Vol 312 ◽  
Author(s):  
R. Biswas ◽  
K. Roos ◽  
M. C. Tringides
Keyword(s):  
Low Temperature ◽  
Thermal Diffusion ◽  
Ultrathin Films ◽  
Surface Display ◽  
Landing Site ◽  
Lateral Motion ◽  
Temperature Growth ◽  
Dynamics Simulations ◽  
Three Body ◽  
Open Question

AbstractLow temperature (T<150 K) RHEED oscillations during the growth of ultrathin films suggest the presence of substantial adatom mobility. In most systems thermal diffusion can not account for the observed oscillations, and the origin of the oscillations is an open question. Experiments on Ag/Si(111) at 150 K demonstrate the absence of thermal diffusion due to the observed scaling in the RHEED intensity for different flux rates. We have performed molecular dynamics simulations to understand the mechanisms of RHEED oscillations at low temperature. Classical two- and three-body Si potentials were used together with an adatom mass that is 3.84 times the Si mass to account for the Ag/Si mass ratio. Results indicate that the landing site for the adatom is very important to predict whether a particular adatom will display lateral motion or not. A fraction of the adatoms incident near a maximum of the potential energy surface display significant lateral motion. The substrate stiffness for Ag/Si results in an energy transfer process which is much slower than that in fcc/fcc systems.

scholarly journals Electrical Breakdown Mechanism of Transformer Oil with Water Impurity: Molecular Dynamics Simulations and First-Principles Calculations

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 123
Author(s):  
Bin Cao ◽  
Ji-Wei Dong ◽  
Ming-He Chi
Keyword(s):  
Molecular Dynamics ◽  
Thermal Diffusion ◽  
First Principles ◽  
Electrical Breakdown ◽  
Transformer Oil ◽  
Water Molecules ◽  
Conducting Channel ◽  
Breakdown Mechanism ◽  
Water Impurity ◽  
Dynamics Simulations

Water impurity is the essential factor of reducing the insulation performance of transformer oil, which directly determines the operating safety and life of a transformer. Molecular dynamics simulations and first-principles electronic-structure calculations are employed to study the diffusion behavior of water molecules and the electrical breakdown mechanism of transformer oil containing water impurities. The molecular dynamics of an oil-water micro-system model demonstrates that the increase of aging acid concentration will exponentially expedite thermal diffusion of water molecules. Density of states (DOS) for a local region model of transformer oil containing water molecules indicates that water molecules can introduce unoccupied localized electron-states with energy levels close to the conduction band minimum of transformer oil, which makes water molecules capable of capturing electrons and transforming them into water ions during thermal diffusion. Subsequently, under a high electric field, water ions collide and impact on oil molecules to break the molecular chain of transformer oil, engendering carbonized components that introduce a conduction electronic-band in the band-gap of oil molecules as a manifestation of forming a conductive region in transformer oil. The conduction channel composed of carbonized components will be eventually formed, connecting two electrodes, with the carbonized components developing rapidly under the impact of water ions, based on which a large number of electron carriers will be produced similar to “avalanche” discharge, leading to an electrical breakdown of transformer oil insulation. The water impurity in oil, as the key factor for forming the carbonized conducting channel, initiates the electric breakdown process of transformer oil, which is dominated by thermal diffusion of water molecules. The increase of aging acid concentration will significantly promote the thermal diffusion of water impurities and the formation of an initial conducting channel, accounting for the degradation in dielectric strength of insulating oil containing water impurities after long-term operation of the transformer.

A novel low-temperature growth of uniform CuInS2 thin films and their application in selenization/sulfurization-free CuInS2 solar cells

2021 ◽  
Vol 26 ◽  
pp. 102050
Author(s):  
Mehdi Dehghani ◽  
Ershad Parvazian ◽  
Nastaran Alamgir Tehrani ◽  
Nima Taghavinia ◽  
Mahmoud Samadpour
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Low Temperature ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Cuins2 Thin Films

scholarly journals Practical Route for the Low-Temperature Growth of Large-Area Bilayer Graphene on Polycrystalline Nickel by Cold-Wall Chemical Vapor Deposition

ACS Omega ◽  
2021 ◽  
Author(s):  
Muhammad Aniq Shazni Mohammad Haniff ◽  
Nur Hamizah Zainal Ariffin ◽  
Poh Choon Ooi ◽  
Mohd Farhanulhakim Mohd Razip Wee ◽  
Mohd Ambri Mohamed ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Bilayer Graphene ◽  
Cold Wall ◽  
Polycrystalline Nickel ◽  
Large Area ◽  
Temperature Growth ◽  
Low Temperature Growth

Low-Temperature Growth of Ferroelectric Hf0.5Zr0.5O2 Thin Films Assisted by Deep Ultraviolet Light Irradiation

2021 ◽  
Vol 3 (3) ◽  
pp. 1244-1251
Author(s):  
Hyunjin Joh ◽  
Gopinathan Anoop ◽  
Won-June Lee ◽  
Dipjyoti Das ◽  
Jun Young Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Ultraviolet Light ◽  
Light Irradiation ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Ultraviolet Light Irradiation ◽  
Deep Ultraviolet

The influence of preinfection cold hardening and disease development period on the interaction between barley yellow dwarf virus and cold stress tolerance in wheat

1983 ◽  
Vol 61 (7) ◽  
pp. 1935-1940 ◽  
Author(s):  
C. J. Andrews ◽  
Y. C. Paliwal
Keyword(s):  
Low Temperature ◽  
Barley Yellow Dwarf Virus ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Dry Matter Content ◽  
Disease Development ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Barley Yellow Dwarf ◽  
Yellow Dwarf Virus

Cold hardness and ice encasement tolerance of 'Fredrick' and 'Norstar' winter wheats as affected by infection with barley yellow dwarf virus (BYDV) were determined during inoculation, disease development periods, and low-temperature growth. Plants were either prehardened to cold, or warm grown before infection; two disease development periods (DDP) were utilized. A long DDP induced greater pathogenesis and greater hardiness reduction than a short DDP. The effect of virus infection on the final level of hardiness of prehardened plants was generally greater than on that of nonprehardened plants. Viral infection reduced hardiness up to 3.5 °C in 'Fredrick' wheat, but reductions of 6–10 °C below hardiness potential were recorded after certain environmental regimes allowing disease development. Ice tolerance was reduced by BYDV infection in early low-temperature growth but was increased by infection after 4 months at low temperature. This increase in survival was associated with higher dry matter content in infected than in noninfected plants.

scholarly journals Low temperature growth of FePt and CoPt films on MgO(111) substrate

2011 ◽  
Vol 109 (7) ◽  
pp. 07B743 ◽  
Author(s):  
Fu-Te Yuan ◽  
A. C. Sun ◽  
Jui-Kuo Mei ◽  
W. M. Liao ◽  
Jen-Hwa Hsu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Growth ◽  
Low Temperature Growth
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