Step-Edge Barriers on GaAs(001)

1995 ◽  
Vol 399 ◽  
Author(s):  
P. Šmilauer ◽  
D.D. Vvedensky
Keyword(s):  
Kinetic Monte Carlo ◽  
Step Edge ◽  
Layer By Layer ◽  
Vicinal Surfaces ◽  
Activation Barriers ◽  
Long Time ◽  
Kinetic Monte Carlo Simulations ◽  
Simulated Surface ◽  
Constant Slope ◽  
Surface Morphologies

ABSTRACTWe investigate growth of GaAs(001) using kinetic Monte Carlo simulations of a very simple atomistic solid-on-solid model. The key features of this model are a short-range incorporation process of freshly deposited atoms and additional activation barriers to interlayer transport. Both are required to obtain close agreement between measured electron-diffraction intensities and simulated surface step densities during growth and post-growth equilibration on vicinal surfaces. This model is used to study long-time evolution of the surface morphology. Large pyramid-like features develop during growth on a singular surface which coarsen in time while maintaining an approximately constant slope. Growth on a vicinal surface is also found to be unstable. Simulated surface morphologies are compared with recent work using atomic-force microscopy. Finally, we show how a suitably modified version of this model helps to explain the recently observed phenomenon of re-entrant layer-by-layer chemical-beam etching of a singular GaAs(001) surface. The central features responsible for this behavior are the site selectivity of the etching process combined with step-edge barriers to interlayer adatom migration.

Examination of the Effect of Vacancy Detachment Rates on Kinetic Monte Carlo Simulations of bcc Metals

MRS Advances ◽  
2016 ◽  
Vol 1 (35) ◽  
pp. 2489-2494 ◽  
Author(s):  
Richard T Hoffman ◽  
Alexander P Moore ◽  
Chaitanya S Deo
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Void Formation ◽  
Binding Energies ◽  
Size Dependent ◽  
Bcc Metals ◽  
Bcc Lattice ◽  
Long Time ◽  
Kinetic Monte Carlo Simulations ◽  
Dynamics Simulations

ABSTRACTA Kinetic Monte Carlo simulation, using a modified version of the SPPARKS code, of simple defects and complex vacancy clusters was run on a bcc lattice. In this simulation the complexity of void formation was varied by introducing a detachment rate for individual vacancies leaving the void and either treating this value as constant for all size voids or having this value be dependent on the size of the void. Molecular Dynamics simulations were used to determine the binding energies of vacancies for voids of varying size. The simulation was then run over long time periods to determine the number of defects in the simulation under irradiation conditions. It was found that the additional complexity of size dependent void detachment rates had little effect on the defect concentrations and thus a constant barrier should be sufficient for simulations of voids in bcc metals.

Evolution of surface morphology during epitaxial growth

1993 ◽  
Vol 344 (1673) ◽  
pp. 493-505 ◽  
Keyword(s):  
Epitaxial Growth ◽  
Large Scale ◽  
High Energy ◽  
Atomic Scale ◽  
High Energy Electron ◽  
Vicinal Surfaces ◽  
Basic Model ◽  
Surface Steps ◽  
Simulated Surface ◽  
Surface Morphologies

We examine the type of information that can be obtained from Monte Carlo simulations of epitaxial growth. A basic model will be first introduced and some of the features that make it suitable for describing both atomic-scale processes and large-scale morphologies will be pointed out. The ability of this model to reproduce experimental data will then be addressed. The first example discussed will be growth on GaAs(OO1) vicinal surfaces, where the density of surface steps on the simulated surfaces reproduces quantitatively the evolution of the reflection high-energy electron diffraction (RHEED) intensity oscillations for appropriately chosen growth and diffraction conditions. This work will then be used as a basis for examining the predictions of the simulated surface morphologies on patterned substrates, based on comparisons with micro-RHEED measurements. Extensions of the basic model to more complex growth scenarios where the atomic constituents are delivered in the form of heteroatomic molecules will also be discussed.

Model for the catalytic reduction of no on a surface with species desorption and impurities that cannot desorb

2021 ◽  
Author(s):  
E. J. Hernández ◽  
G. M. Buendía
Keyword(s):  
Catalytic Reduction ◽  
Kinetic Monte Carlo ◽  
Dynamical Behavior ◽  
Square Lattice ◽  
Modified Model ◽  
Reduction Of No ◽  
Large Fluctuations ◽  
Long Time ◽  
Kinetic Monte Carlo Simulations ◽  
The Stability

The dynamical behavior of a modified Yaldram–Khan model for the catalytic reduction of NO on a surface is studied by Kinetic Monte Carlo simulations. In this modified model, temperature effects are incorporated as desorption rates of the N and CO species. How the presence of contaminants in the gas phase affects the catalytic process is also analyzed by including impurities that can be adsorbed on the lattice and once there remain inert. When N desorption is included, a reactive window appears that is not present in the original YK model on a square lattice. When CO desorption is added large fluctuations appear in the coverages, the system can take a long time to stabilize, during this period, a long lasting reactive state exists that disappears when the stability is reached. When nondesorbing impurities are added, the discontinuous transition to a CO poisoned phase that presents the original YK model disappears, the coverages become continuous, and a nonreactive steady-state is rapidly reached.

Mound Formation and Coarsening in Homoepitaxial Growth

1996 ◽  
Vol 440 ◽  
Author(s):  
Jacques G. Amar ◽  
Fereydoon Family
Keyword(s):  
Critical Temperature ◽  
Kinetic Monte Carlo ◽  
Layer Growth ◽  
Layer By Layer ◽  
Island Nucleation ◽  
Homoepitaxial Growth ◽  
Kinetic Monte Carlo Simulations ◽  
Temperature Deposition ◽  
Mound Formation ◽  
Positive Step

AbstractThe effects of instabilities which lead to mound formation and coarsening in homoepitaxial growth on metal (100) surfaces are discussed. These include an instability due to the Ehrlich-Schwoebel step barrier to interlayer diffusion as well as an instability due to step-adatom attraction at ascending steps. A unified picture of the effects of attractive and repulsive interactions at ascending and descending steps on surface morphology and island nucleation is presented. An analytic calculation of the selected mound angle and critical temperature for mound formation as a function of both the Ehrlich-Schwoebel step barrier and the barrier to diffusion towards an ascending step is also presented. Depending on the sign of the step barrier and the magnitude of the prefactor for diffusion over a step various scenarios are possible, including the existence of a critical temperature for mound formation above which (for a positive step barrier) or below which (for a negative step barrier) quasi-layer-by-layer growth will be observed. A theoretical analysis also leads to an accurate prediction of the observed mound angle for Fe/Fe(100) deposition at room temperature. The general dependence of the mound angle, surface skewness, and mound coarsening exponent on temperature, deposition rate, and strength of the step barrier is also studied via kinetic Monte Carlo simulations of bcc(100) growth and compared with recent experiments.

scholarly journals Stochastic Models of Epitaxial Growth

2011 ◽  
Vol 1318 ◽  
Author(s):  
Dionisios Margetis ◽  
Paul N. Patrone ◽  
T. L. Einstein
Keyword(s):  
Kinetic Monte Carlo ◽  
Mean Field ◽  
Spatial Dimension ◽  
Stochastic Equations ◽  
Vicinal Surfaces ◽  
Field Approach ◽  
Material Deposition ◽  
Elastic Dipole ◽  
Kinetic Monte Carlo Simulations ◽  
Step Fluctuations

ABSTRACTWe study theoretical aspects of step fluctuations on vicinal surfaces by adding conservative white noise to the Burton-Cabrera-Frank model in one spatial dimension. We consider material deposition from above, as well as entropic and elastic-dipole step repulsions. Two approaches are discussed: (i) the linearization of stochastic equations when fluctuations are small, which captures correlations; and (ii) a mean field approach, which leaves out correlations but captures nonlinearities. Comparisons to kinetic Monte-Carlo simulations are presented.

Step-edge induced area selective growth: a kinetic Monte Carlo study

RSC Advances ◽  
2014 ◽  
Vol 4 (48) ◽  
pp. 25005-25010 ◽  
Author(s):  
Heng Zhang ◽  
Gang Liu ◽  
Wenchong Wang ◽  
Lifeng Chi ◽  
Shiling Yuan
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Study ◽  
Layer Growth ◽  
Selective Growth ◽  
Step Edge ◽  
Layer By Layer ◽  
Growth Layer ◽  
Three Stages ◽  
Nucleation Growth

Three stages of step-edge induced selective growth were proposed: step-edge induced growth, layer-by-layer growth and central nucleation growth.

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