Numerical Simulation of Diffusion Controlled Surface Evolution

1993 ◽  
Vol 317 ◽  
Author(s):  
Cheng-Hsin Chiu ◽  
Huajian Gao
Keyword(s):  
Numerical Simulation ◽  
Numerical Methods ◽  
Diffusion Process ◽  
Surface Diffusion ◽  
Morphological Evolution ◽  
Two Dimensional ◽  
Lateral Direction ◽  
Surface Evolution ◽  
Diffusion Controlled ◽  
Heteroepitaxial Layers

ABSTRACTAs a model for Stranski-Krastanow island formation in strained heteroepitaxial layers, this paper investigates the surface-diffusion controlled morphological evolution of a two dimensional semi-infinite solid loaded in the lateral direction. Numerical Methods are developed to simulate the surface diffusion process, and examples are presented to demonstrate three distinct evolution patterns which are characterized by two critical wavelengths. The results show that, according to the wavelength, a slightly wavy surface can evolve into a cusped, a smoothly undulating, or a flat configuration. The diffusion wavelength and cusp-formation time compare favorably with recent experimental observations.

A Numerical Study of Stress Controlled Surface Diffusion During Epitaxial Film Growth

1994 ◽  
Vol 356 ◽  
Author(s):  
Cheng-Hsin Chiu ◽  
Huajian Gao
Keyword(s):  
Surface Diffusion ◽  
Film Growth ◽  
Numerical Study ◽  
Morphological Evolution ◽  
Film Surface ◽  
Numerical Results ◽  
Simultaneous Action ◽  
Surface Evolution ◽  
Growth Modes ◽  
Film Substrate

AbstractA two-dimensional numerical simulation is performed to model the morphological evolution of a strained film growing heteroepitaxially on a substrate under simultaneous action of vapor deposition and surface diffusion. To facilitate numerical implementation, a continuum boundary layer model is proposed to account for the influence of film/substrate interface on the film growth pattern. Discussions are focused on the Stranski-Krastanow growth mode, although our model is capable of explaining Frank-van der Merwe and Volmer-Weber growth modes as well. Both first-order perturbation and numerical results are developed to demonstrate that the film surface tends to remain flat during the initial stage of growth and that surface roughening occurs once the film thickness exceeds a critical value, in consistency with experimentally observed patterns of S-K growth. Numerical results further show that, depending on the deposition rate, the surface evolution could lead to a steady state morphology, unstable cusp formation, or growing islands with flattened valleys.

Numerical Simulation of a 2D Layered Anode for use in Lithium-Ion Batteries

2021 ◽  
pp. 2150032
Author(s):  
Alexander Galashev
Keyword(s):  
Numerical Simulation ◽  
Numerical Methods ◽  
Lithium Ion Batteries ◽  
Electronic States ◽  
Lithium Ion ◽  
Graphite Substrate ◽  
Technological Problem ◽  
Two Dimensional ◽  
Normal Stresses ◽  
Electrically Conductive

An important technological problem is solved by numerical methods. Doping of silicene with phosphorus allows changing the morphology of the walls of the silicene channel without reducing their strength. The structure of lithium packings in the channels is studied in detail. The distribution of normal stresses in the walls of the channel before lithium intercalation and after complete lithium filling is determined. The calculated densities of electronic states allow us to conclude that both doped and undoped silicene on a graphite substrate become electrically conductive. The studied two-dimensional silicene can be used as an anode for next-generation lithium-ion batteries.

Three Dimensional Simulation of the Morphological Evolution of a Strained Film on a Thick Substrate

1998 ◽  
Vol 529 ◽  
Author(s):  
Cheng-hsin Chiu
Keyword(s):  
Morphological Evolution ◽  
Three Dimensional ◽  
Kinetic Process ◽  
Two Dimensional ◽  
Surface Evolution ◽  
Thick Substrate ◽  
Dimensional Simulation

AbstractThis paper presents a three-dimensional simulation for the surface evolution of a strained film on a thick substrate. The simulation shows that an initially random morphology will first transform into a profile dominated by two-dimensional ridges, and then into a three-dimensional island surface. The simulation also demonstrates that the ridge-island transition is a kinetic process which can be delayed by changing the initial morphology.

Numerical Simulation of the Performance of a Sudden Expansion With Fence Viewed as a Diffuser in Low Reynolds Number Regime

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
S. Chakrabarti ◽  
S. Rao ◽  
D. K. Mandal
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Aspect Ratio ◽  
Diffusion Process ◽  
Static Pressure ◽  
Low Reynolds Number ◽  
Simple Algorithm ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Low Reynolds

In this paper, the results of numerical simulation on the performance of a sudden expansion with fence viewed as a diffuser are presented. The two-dimensional steady differential equations for conservation of mass and momentum have been solved using the semi-implicit method for pressure-linked equations (SIMPLE) algorithm. The Reynolds number is in the range of 20–100 and fence subtended angle (FSA) between 10 deg and 30 deg. An aspect ratio of 2 is fixed for all the computations. The effect of each variable on average static pressure and diffuser effectiveness has been studied. Computations have revealed that for higher Reynolds number, the use of a fence always increases the effectiveness of the diffusion process when compared with a simple sudden expansion configuration. In low Reynolds number regime, depending on the positioning of the fence and the fence subtended angle, the fence may increase or decrease the diffuser effectiveness in comparison with sudden expansion without fence.

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