The Morphological Stability of Strained Epitaxial Layers

1996 ◽  
Vol 440 ◽  
Author(s):  
B. W. Wessels
Keyword(s):  
Thin Films ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Epitaxial Layers ◽  
Two Dimensional ◽  
Morphological Stability

AbstractThe morphological stability of strained-layer thin films is analyzed using classical nucleation theory. For the case where strain relaxation occurs by formation of coherent islands, the model predicts that the critical thickness for transition from two-dimensional (2D) to three dimensional (3D) growth depends inversely on the square of the misfit. The predicted dependence of critical thickness on misfit is in agreement with recent experimental studies on the heteropitaxy of III-V compounds.

Nucleation and Growth Characteristics of Thin Metal Films

1971 ◽  
Vol 29 ◽  
pp. 216-217
Author(s):  
H. P. Singh ◽  
L. E. Murr
Keyword(s):  
Thin Films ◽  
Three Dimensional ◽  
Metal Films ◽  
Nucleation And Growth ◽  
Growth Characteristics ◽  
Thin Metal ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Thin Metal Films ◽  
Initial Deposition

This paper reports observations of nucleation and growth characteristics of thin metal films vapor deposited onto heated sodium chloride substrates. An attempt is made to explain the differences in nucleation and growth characteristics on the basis of classical nucleation theory.Thin metal films were prepared by vapor deposition onto heated NaCl (001) substrates in a commercial vacuum unit using a constant evaporation rate of approximately 1000 Å/sec. In the case of discontinuous thin films, approximately 200 Å of carbon was deposited for support. Samples for electron microscopy were prepared by standard techniques and were observed at 125 kV. Figs. 1(a) to (c) show a growth sequence of gold thin films characterized by 1) the formation of random, three dimensional, isolated nuclei at initial deposition, and their growth with further deposition predominantly by surface diffusion; 2) coalescence of these nuclei forming bigger islands; 3) the flattening of islands and formation of network structure : and 4) the filling up of these network structures with further deposition forming a continuous film.

scholarly journals Phase-field modeling of grain evolutions in additive manufacturing from nucleation, growth, to coarsening

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Min Yang ◽  
Lu Wang ◽  
Wentao Yan
Keyword(s):  
Additive Manufacturing ◽  
Phase Field ◽  
Field Model ◽  
Three Dimensional ◽  
Phase Field Model ◽  
Nucleation Theory ◽  
Experimental Result ◽  
Classical Nucleation Theory ◽  
Validation Experiment ◽  
Powder Particles

AbstractA three-dimensional phase-field model is developed to simulate grain evolutions during powder-bed-fusion (PBF) additive manufacturing, while the physically-informed temperature profile is implemented from a thermal-fluid flow model. The phase-field model incorporates a nucleation model based on classical nucleation theory, as well as the initial grain structures of powder particles and substrate. The grain evolutions during the three-layer three-track PBF process are comprehensively reproduced, including grain nucleation and growth in molten pools, epitaxial growth from powder particles, substrate and previous tracks, grain re-melting and re-growth in overlapping zones, and grain coarsening in heat-affected zones. A validation experiment has been carried out, showing that the simulation results are consistent with the experimental results in the molten pool and grain morphologies. Furthermore, the grain refinement by adding nanoparticles is preliminarily reproduced and compared against the experimental result in literature.

scholarly journals Nanometer-Thick [(FPEA)2PbX4; X=I, Br] 2D Halide Perovskite Based Thin Films for Pollutant Detection and Nonconventional Photocatalytic Degradation

2021 ◽  
Author(s):  
Arindam Mondal ◽  
Akash Lata ◽  
Aarya Prabhakaran ◽  
Satyajit Gupta
Keyword(s):  
Thin Films ◽  
Photocatalytic Degradation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Reduced Dimensionality ◽  
P Application ◽  
Halide Perovskites ◽  
Halide Perovskite ◽  
Pollutant Detection

Application of three-dimensional (3D)-halide perovskites (HaP) in photocatalysis encourages the new exercise with two-dimensional (2D) HaP based thin-films for photocatalytic degradation of dye. The reduced dimensionality to 2D-HaPs, with a...

Microstructure Evolution of Epitaxial (Ba, Sr) TiO3/ (001) HgO Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
V.A. Alyoshin ◽  
E.V. Sviridov ◽  
V.I.M. Hukhortov ◽  
I.H. Zakharchenko ◽  
V.P. Dudkevich
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Microstructure Evolution ◽  
Three Dimensional ◽  
Gas Pressure ◽  
Smooth Surfaces ◽  
Two Dimensional ◽  
Surface Versus ◽  
Deposition Conditions

ABSTRACTSurface and cross-section relief evolution of ferroelectric epitaxial (Ba,Sr)TiO3 films rf-sputtered on (001) HgO crystal cle-avage surface versus the oxygen worKing gas pressure P and subst-rate temperature T were studied. Specific features of both three-dimensional and two-dimensional epitaxy mechanisms corresponding to various deposition conditions were revealed. Difference between low and high P-T-value 3D epitaxy was established. The deposition of films with mirror-smooth surfaces and perfect interfaces is shown to be possible.

scholarly journals Tip-Based Nanomachining on Thin Films: A Mini Review

2021 ◽  
Author(s):  
Shunyu Chang ◽  
Yanquan Geng ◽  
Yongda Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Data Storage ◽  
Three Dimensional ◽  
Maintenance Cost ◽  
Two Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current State ◽  
Two Dimensional Materials

AbstractAs one of the most widely used nanofabrication methods, the atomic force microscopy (AFM) tip-based nanomachining technique offers important advantages, including nanoscale manipulation accuracy, low maintenance cost, and flexible experimental operation. This technique has been applied to one-, two-, and even three-dimensional nanomachining patterns on thin films made of polymers, metals, and two-dimensional materials. These structures are widely used in the fields of nanooptics, nanoelectronics, data storage, super lubrication, and so forth. Moreover, they are believed to have a wide application in other fields, and their possible industrialization may be realized in the future. In this work, the current state of the research into the use of the AFM tip-based nanomachining method in thin-film machining is presented. First, the state of the structures machined on thin films is reviewed according to the type of thin-film materials (i.e., polymers, metals, and two-dimensional materials). Second, the related applications of tip-based nanomachining to film machining are presented. Finally, the current situation of this area and its potential development direction are discussed. This review is expected to enrich the understanding of the research status of the use of the tip-based nanomachining method in thin-film machining and ultimately broaden its application.

scholarly journals Theoretical and experimental studies of highly selective planar two-dimensional Bragg structures based on dielectric waveguides in the terahertz frequency range

2019 ◽  
Vol 30 ◽  
pp. 07009
Author(s):  
Naum Ginzburg ◽  
Nikolay Peskov ◽  
Vladislav Zaslavsky ◽  
Ekaterina Kocharovskaya ◽  
Andrey Malkin ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Dielectric Waveguides ◽  
Two Dimensional ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Three Dimensional Modeling ◽  
Bragg Structures

Based on theoretical approach and three-dimensional modeling using the CST Microwave Studio code, planar dielectric two-dimensional Bragg structures in terahertz frequency range were developed and manufactured. Proof-of-principle electrodynamic experiments on the “cold” testing of these structures were carried out. It is shown that the experimental results are in good agreement with the theoretical predicts, including the existence of the highest Q mode inside the Bragg reflection band in the absence of periodicity defects.

Chemistry-mediated two-dimensional to three-dimensional transition of In thin films

2004 ◽  
Vol 84 (26) ◽  
pp. 5401-5403 ◽  
Author(s):  
H. L. Wei ◽  
Hanchen Huang ◽  
C. H. Woo ◽  
X. X. Zhang ◽  
L. G. Zhou
Keyword(s):  
Thin Films ◽  
Three Dimensional ◽  
Two Dimensional

Molecular Dynamics Simulation of Nano Cluster-Seed Effects on Heterogeneous Nucleation

2009 ◽  
Author(s):  
Donguk Suh ◽  
Seung-chai Jung ◽  
Woong-sup Yoon
Keyword(s):  
Molecular Dynamics ◽  
Heterogeneous Nucleation ◽  
Three Dimensional ◽  
Seed Mass ◽  
Nucleation Theory ◽  
Dynamics Simulation ◽  
Classical Nucleation Theory ◽  
Supersaturation Ratio ◽  
Order Of Magnitude ◽  
Nano Cluster

A three-dimensional heterogeneous nucleation is simulated by classical molecular dynamics, where the Lennard-Jones gas and solid nano cluster-seed molecules have argon and aluminum properties, respectively. All dimensions of the wall are periodic and a soft core carrier gas within the system controls the temperature rise induced by latent heat of condensation. There are three shapes of cluster-seeds being cube, rod, and sphere, three classes of masses, and the simulation took place under nine supersaturation ratios, making a total of 81 calculations. An analysis of variance was performed under a three-way layout to analyze the cluster-seed and supersaturation ratio effects on the system. For supersaturation ratios above the critical value nucleation rates were evaluated, below growth rates, and overall liquefaction rates were each defined and calculated. Results show that the supersaturation ratio dominantly controls all rates, but seed characteristics are important for the growth of the largest cluster under the critical supersaturation ratio. Overall liquefaction increases subject to an escalation of supersaturation ratio and seed mass. However, the significance of the supersaturation ratio for overall liquefaction suggests that thermal diffusion is more dominant than mass interactions for this system. Homogeneous characteristics are also compared with the heterogeneous system to find that though nucleation may occur for an insufficient supersaturation ratio when a seed is within the system, the addition of a seed does not in fact facilitate the increase in rates of the phenomena at high supersaturation ratios. Finally a comparison with the classical nucleation theory asserts a 3 to 4 order of magnitude difference, which is within the lines of deviation when it comes to theory and molecular simulations.

scholarly journals Probing Two-Dimensional vs Three-Dimensional Molecular Aggregation in Metal-Free Tetraphenylporphyrin Thin Films by Optical Anisotropy

2014 ◽  
Vol 118 (29) ◽  
pp. 15649-15655 ◽  
Author(s):  
G. Bussetti ◽  
M. Campione ◽  
L. Ferraro ◽  
L. Raimondo ◽  
B. Bonanni ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Anisotropy ◽  
Three Dimensional ◽  
Molecular Aggregation ◽  
Two Dimensional ◽  
Metal Free

Optimal Javelin Release

1995 ◽  
Vol 11 (4) ◽  
pp. 371-394 ◽  
Author(s):  
Russell J. Best ◽  
Roger M. Bartlett ◽  
Richard A. Sawyer
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
High Standard ◽  
Flight Simulation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Simulation Research ◽  
Simulation Evaluation ◽  
Model And Simulation ◽  
Two Dimensional Model

This paper reports a study of the optimal release of men's and women's new and old rule javelins involving modeling, simulation, optimization (including sensitivity analysis), and simulation evaluation. Because of the lack of repro-ducibility in earlier results of two-dimensional flight simulation research, the paper presents a continuation of the two-dimensional model used previously. As expected, each javelin was found to have a different optimal release for a given individual, and the optimal release varied with the thrower's nominal release speed. A limited degree of simulation evaluation was achieved by comparison of the model and simulation results with measured throws. Within the constraints of measurement error, this tended to support both the adequacy of the two-dimensional model and the results of the simulations for such high standard throws. However, further experimental studies to quantify the angle of yaw (sideslip) in measured wind conditions are recommended to assess any changes needed to the two-dimensional model of javelin throwing and to determine the advisability of including this three-dimensional aspect of javelin release in future simulations.

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