Nanoscratching-Induced Phase Tansformation of Monocrystalline Silicon – The Depth-of-Cut Effect

2009 ◽  
Vol 76-78 ◽  
pp. 387-391 ◽  
Author(s):  
Kausala Mylvaganam ◽  
Liang Chi Zhang
Keyword(s):  
Molecular Dynamics ◽  
Phase Transformations ◽  
Amorphous Silicon ◽  
Significant Influence ◽  
Crystalline Phase ◽  
Silicon Surface ◽  
Monocrystalline Silicon ◽  
Depth Of Cut ◽  
Initial Impression ◽  
Dynamics Simulations

This paper explores the effect of the depth-of-cut of an indenter on the phase transformations during nanoscratching on monocrystalline silicon on the Si(100) orientation. The analysis was carried out by molecular dynamics simulations. It was found that the depth-of-cut and the impingement direction of the indenter had a significant influence on the phase transformations in the initial impression region. At a relatively low depth-of-cut, only amorphous silicon was formed on the scratched surface. When the indenter impinged on a silicon surface with an angle, a bct5-Si crystalline phase in the initial impression region would emerge.

scholarly journals Molecular Dynamics Simulations of Vacancy Generation and Migration near a Monocrystalline Silicon Surface during Energetic Cluster Ion Implantation

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 146
Author(s):  
Guoying Liang ◽  
Haowen Zhong ◽  
Yinong Wang ◽  
Shijian Zhang ◽  
Mofei Xu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ion Implantation ◽  
Molecular Dynamics Simulations ◽  
Silicon Surface ◽  
Amorphous Structure ◽  
Monocrystalline Silicon ◽  
Vacancy Generation ◽  
Cluster Ion ◽  
And Migration ◽  
Dynamics Simulations

The process of ion implantation often involves vacancy generation and migration. The vacancy generation and migration near a monocrystalline silicon surface during three kinds of energetic Si35 cluster ion implantations were investigated by molecular dynamics simulations in the present work. The patterns of vacancy generation and migration, as well as the implantation-induced amorphous structure, were analyzed according to radial distribution function, Wigner–Seitz cell, and identify diamond structure analytical methods. A lot of vacancies rapidly generate and migrate in primary directions and form an amorphous structure in the first two picoseconds. The cluster with higher incident kinetic energy can induce the generation and migration of more vacancies and a deeper amorphous structure. Moreover, boundaries have a loading–unloading effect, where interstitial atoms load into the boundary, which then acts as a source, emitting interstitial atoms to the target and inducing the generation of vacancies again. These results provide more insight into doping silicon via ion implantation.

Effect of bct-5 Si on the Indentation of Monocrystalline Silicon

2011 ◽  
Vol 117-119 ◽  
pp. 666-669 ◽  
Author(s):  
Kausala Mylvaganam ◽  
Liang Chi Zhang
Keyword(s):  
Molecular Dynamics ◽  
Phase Transformations ◽  
Molecular Dynamics Simulations ◽  
Crystalline Silicon ◽  
Monocrystalline Silicon ◽  
Loading Conditions ◽  
Dynamics Simulations

Mono-crystalline silicon experiences various phase transformations under different loading conditions. This paper reveals, with the aid of molecular dynamics simulations, that scratching the silicon {001} surface along the [110] direction under a load of 0.8 µN or more would produce stable 5 coordinated body centered tetragonal (bct-5) silicon in the subsurface. By examining the effect of this bct-5 silicon on indentation, it was found that the resistant to deformation of bct-5 silicon is higher than a-Si but lower than diamond Si.

Computer-Generated Structural Models for a-Si:H

1988 ◽  
Vol 141 ◽  
Author(s):  
Laurent J. Lewis ◽  
Normand Mousseau ◽  
FranÇois Drolet
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Amorphous Silicon ◽  
Periodic Boundary ◽  
Hydrogenated Amorphous Silicon ◽  
Structural Models ◽  
Periodic Boundary Conditions ◽  
Dynamics Simulations ◽  
Hydrogenated Amorphous ◽  
Good Agreement

AbstractA new algorithm for generating fully-coordinated hydrogenated amorphous silicon models with periodic boundary conditions is presented. The hydrogen is incorporated into an a-Si matrix by a bond-switching process similar to that proposed by Wooten, Winer, and Weaire, making sure that four-fold coordination is preserved and that no rings with less than 5 members are created. After each addition of hydrogen, the structure is fully relaxed. The models so obtained, to be used as input to molecular dynamics simulations, are found to be in good agreement with experiment. A model with 12 at.% H is discussed in detail.

Effects of tensile temperatures on phase transformations in zirconium by molecular dynamics simulations

2021 ◽  
Vol 28 (7) ◽  
pp. 1932-1945
Author(s):  
Ke-ying An ◽  
Xiao-qin Ou ◽  
Xing-long An ◽  
Hao Zhang ◽  
Song Ni ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Phase Transformations ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulations

scholarly journals Investigation of the Subsurface Temperature Effects on Nanocutting Processes via Molecular Dynamics Simulations

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1220
Author(s):  
Michail Papanikolaou ◽  
Francisco Rodriguez Hernandez ◽  
Konstantinos Salonitis
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Process Parameters ◽  
Cutting Forces ◽  
Rake Angle ◽  
Von Mises Stress ◽  
Depth Of Cut ◽  
Subsurface Temperature ◽  
Workpiece Material ◽  
Dynamics Simulations

In this investigation, three-dimensional molecular dynamics simulations have been performed in order to investigate the effects of the workpiece subsurface temperature on various nanocutting process parameters including cutting forces, friction coefficient, as well as the distribution of temperature and equivalent Von Mises stress at the subsurface. The simulation domain consists of a tool with a negative rake angle made of diamond and a workpiece made of copper. The grinding speed was considered equal to 100 m/s, while the depth of cut was set to 2 nm. The obtained results suggest that the subsurface temperature significantly affects all of the aforementioned nanocutting process parameters. More specifically, it has been numerically validated that, for high subsurface temperature values, thermal softening becomes dominant and this results in the reduction of the cutting forces. Finally, the dependency of local properties of the workpiece material, such as thermal conductivity and residual stresses on the subsurface temperature has been captured using numerical simulations for the first time to the authors’ best knowledge.

Nucleation Process During Excimer Laser Annealing of Amorphous Silicon Thin Films on Glass: A Molecular-dynamics Study

2006 ◽  
Vol 958 ◽  
Author(s):  
Shinji Munetoh ◽  
Takanori Mitani ◽  
Takahide Kuranaga ◽  
Teruaki Motooka
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Amorphous Silicon ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Surface Region ◽  
Excimer Laser Annealing ◽  
Silicon Thin Films ◽  
Steady State Temperature ◽  
Dynamics Simulations

ABSTRACTWe have performed molecular-dynamics simulations of heating, melting and recrystallization processes in amorphous silicon (a-Si) thin films deposited on glass during excimer laser annealing. By partially heating the a-Si surface region with 2 nm depth and removing thermal energy from the bottom of the glass substrate, a steady-state temperature profile was obtained in the a-Si layer with the thickness of 15 nm and only the surface region was melted. It was found that nucleation predominantly occurred in the a-Si region as judged by the coordination numbers and diffusion constants of atoms in the region. The results suggest that nucleation occurs in unmelted residual a-Si region during the laser irradiation and then crystal growth proceeds toward liquid Si region under the near-complete melting condition.

Effect of Hydrogenation Temperature on Distribution of Hydrogen Atoms in c-Si and a-Si: Molecular Dynamic Simulations

2016 ◽  
Vol 706 ◽  
pp. 55-59 ◽  
Author(s):  
Mauludi Ariesto Pamungkas ◽  
Rendra Widiyatmoko
Keyword(s):  
Amorphous Silicon ◽  
Silicon Surface ◽  
Prolonged Exposure ◽  
Crystalline Silicon ◽  
Transfer Hydrogenation ◽  
Effect Of Temperature ◽  
Hydrogen Atoms ◽  
Dynamic Simulations ◽  
Hydrogenation Temperature ◽  
Dynamics Simulations

Crystalline silicon and amorphous silicon are main materials of solar cell. Under prolonged exposure to light, silicon will degrade in quality. Hydrogenation is believed can minimize this degradation by reduce the number of dangling bond. These Molecular dynamics simulations are aimed to elaborate the hydrogenation process of crystalline silicon and amorphous silicon and to elucidate effect of temperature on distribution of hydrogen atoms. Reactive Force Field is selected owing to its capability to describe forming and breaking of atomic bonds as well as charge transfer. Hydrogenation is performed at 300 K, 600 K, 900 K, and 1200 K. Hydrogenated silicon surface hinders further hydrogen atoms to be absorbed such that not all deposited Hydrogen atoms are absorbed by silicon surface. Generally, the higher hydrogenation temperature the more hydrogen atoms are absorbed. Increment of temperature from 900 K to 1200 K only enhances a few numbers of absorbed hydrogen atoms. However, it can enable hydrogen atoms to penetrate into deeper silicon substrate. It is also observed that hydrogen atoms can penetrate into amorphous silicon deeper than into crystalline silicon.

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