Effect of Particle Shape on Neck Growth and Shrinkage of Nanoparticles

2017 ◽  
Author(s):  
Elham Mirkoohi ◽  
Rajiv Malhotra
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Flexible Electronics ◽  
Particle Shape ◽  
Functional Materials ◽  
Md Simulations ◽  
Neck Growth ◽  
Nanoparticle Shape ◽  
Temperature Ramps ◽  
Thin Film Devices

Sintering of nanoparticles to create films and patterns of functional materials is emerging as a key manufacturing process in applications like flexible electronics, solar cells and thin-film devices. Further, there is the emerging potential to use nanoparticle sintering to perform additive manufacturing as well. While the effect of nanoparticle size on sintering has been well studied, very little attention has been paid to the effect of nanoparticle shape on the evolution of sintering. This paper uses Molecular dynamics (MD) simulations to determine the influence of particle shape on shrinkage and neck growth for two common nanoparticle shape combinations, i.e., sphere-sphere and sphere-cylinder nanoparticles of different sizes. These sintering indicators are examined at two different temperature ramps. The results from this work show that depending on their relative sizes, degree of neck growth and shrinkage are both significantly affected by the nanoparticle shape. The possibility of using this phenomenon to control density and stresses during nanoparticle sintering are discussed.

Molecular Dynamics Studies of Surface Nucleation and Crystal Growth of Si on SiO2 Substrates

2005 ◽  
Vol 899 ◽  
Author(s):  
Byoung-Min Lee ◽  
Hong Koo Baik ◽  
Takahide Kuranaga ◽  
Shinji Munetoh ◽  
Teruaki Motooka
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Crystal Growth ◽  
Surface Energy ◽  
Md Simulations ◽  
Lower Surface ◽  
Surface Nucleation ◽  
Lower Surface Energy ◽  
Potential Parameters ◽  
Si Thin Film

AbstractMolecular dynamics (MD) simulations of atomistic processes of nucleation and crystal growth of silicon (Si) on SiO2 substrate have been performed using the Tersoff potential based on a combination of Langevin and Newton equations. A new set of potential parameters was used to calculate the interatomic forces of Si and oxygen (O) atoms. It was found that the (111) plane of the Si nuclei formed at the surface was predominantly parallel to the surface of MD cell. The values surface energy for (100), (110), and (111) planes of Si at 77 K were calculated to be 2.27, 1.52, and 1.20 J/m2, respectively. This result suggests that, the nucleation leads to a preferred (111) orientation in the poly-Si thin film at the surface, driven by the lower surface energy.

scholarly journals Adsorption of Silicon-Containing Dendrimers: Effects of Chemical Composition, Structure, and Generation Number

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 552
Author(s):  
Andrey O. Kurbatov ◽  
Nikolay K. Balabaev ◽  
Mikhail A. Mazo ◽  
Elena Yu. Kramarenko
Keyword(s):  
Molecular Dynamics ◽  
Functional Materials ◽  
Md Simulations ◽  
Conformational Behavior ◽  
Carbosilane Dendrimers ◽  
Density Profiles ◽  
The Core ◽  
Adsorbed Atoms ◽  
Composition Structure ◽  
Surface Spreading

We studied the conformational behavior of silicon-containing dendrimers during their adsorption onto a flat impenetrable surface by molecular dynamics (MD) simulations. Four homologous series of dendrimers from the 4th up to the 7th generations were modeled, namely, two types of carbosilane dendrimers differing by the functionality of the core Si atom and two types of siloxane dendrimers with different lengths of the spacers. Comparative analysis of the fractions of adsorbed atoms belonging to various structural layers within dendrimers as well as density profiles allowed us to elucidate not only some general trends but also the effects determined by dendrimer specificity. In particular, it was found that in contrast to the carbosilane dendrimers interacting with the adsorbing surface mainly by their peripheral layers, the siloxane dendrimers with the longer –O–Si(CH3)2–O spacers expose atoms from their interior to the surface spreading out on it. These findings are important for the design of functional materials on the basis of silicon-containing dendrimers.

Molecular-Dynamics Simulations of Hydrogenated Amorphous Silicon Thin-Film Growth

1995 ◽  
Vol 408 ◽  
Author(s):  
T. Ohira ◽  
O. Ukai ◽  
M. Noda ◽  
Y. Takeuchi ◽  
M. Murata ◽  
...  
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Amorphous Silicon ◽  
Film Growth ◽  
Hydrogenated Amorphous Silicon ◽  
Md Simulations ◽  
Thin Film Growth ◽  
Silicon Thin Film ◽  
Radical Migration ◽  
Hydrogenated Amorphous

AbstractWe have performed molecular-dynamics (MD) simulations of hydrogenated amorphous silicon (a-Si:H) thin-film growth using realistic many-body semiclassical potentials developed to describe Si-H interactions. In our MD model, it was assumed that SiH3, SiH2 and the H radicals are main precursors for the thin-film growth. In MD simulations of a-Si:H thin-film growth by many significant precursor SiH3 radicals, we have evaluated average radical migration distances, defect ratios, hydrogen contents, and film growth rates as a function of different incident radical energies to know the effect of the radical energization on the properties. As a result of the comparison between the numerical and experimental results, it was observed that the agreement is fairly good, and that an increase of radical migration distance due to the radical energization is effective on a- Si:H thin-film growth with a low defect.

scholarly journals Theoretical and Experimental Aspects of Current and Future Research on NbO2 Thin Film Devices

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 217
Author(s):  
Denis Music ◽  
Andreas M. Krause ◽  
Pär A. T. Olsson
Keyword(s):  
Thin Film ◽  
Functional Materials ◽  
Future Research ◽  
Research Front ◽  
Extended Defects ◽  
Multiple Interfaces ◽  
Low Thermal Expansion ◽  
Diffusion Studies ◽  
And Storage ◽  
Thin Film Devices

The present research front of NbO2 based memory, energy generation, and storage thin film devices is reviewed. Sputtering plasmas contain NbO, NbO2, and NbO3 clusters, affecting nucleation and growth of NbO2, often leading to a formation of nanorods and nanoslices. NbO2 (I41/a) undergoes the Mott topological transition at 1081 K to rutile (P42/mnm), yielding changes in the electronic structure, which is primarily utilized in memristors. The Seebeck coefficient is a key physical parameter governing the performance of thermoelectric devices, but its temperature behavior is still controversial. Nonetheless, they perform efficiently above 900 K. There is a great potential to improve NbO2 batteries since the theoretical capacity has not been reached, which may be addressed by future diffusion studies. Thermal management of functional materials, comprising thermal stress, thermal fatigue, and thermal shock, is often overlooked even though it can lead to failure. NbO2 exhibits relatively low thermal expansion and high elastic modulus. The future for NbO2 thin film devices looks promising, but there are issues that need to be tackled, such as dependence of properties on strain and grain size, multiple interfaces with point and extended defects, and interaction with various natural and artificial environments, enabling multifunctional applications and durable performance.

Disjoining Pressure Effects in Ultra-Thin Liquid Films in Micropassages—Comparison of Thermodynamic Theory With Predictions of Molecular Dynamics Simulations

2006 ◽  
Vol 128 (12) ◽  
pp. 1276-1284 ◽  
Author(s):  
V. P. Carey ◽  
A. P. Wemhoff
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Vapor Pressure ◽  
Film Thickness ◽  
Md Simulation ◽  
Heat Pipes ◽  
Md Simulations ◽  
Disjoining Pressure ◽  
Pressure Variation ◽  
Equilibrium Vapor Pressure

The concept of disjoining pressure, developed from thermodynamic and hydrodynamic analysis, has been widely used as a means of modeling the liquid-solid molecular force interactions in an ultra-thin liquid film on a solid surface. In particular, this approach has been extensively used in models of thin film transport in passages in micro evaporators and micro heat pipes. In this investigation, hybrid μPT molecular dynamics (MD) simulations were used to predict the pressure field and film thermophysics for an argon film on a metal surface. The results of the simulations are compared with predictions of the classic thermodynamic disjoining pressure model and the Born-Green-Yvon (BGY) equation. The thermodynamic model provides only a prediction of the relation between vapor pressure and film thickness for a specified temperature. The MD simulations provide a detailed prediction of the density and pressure variation in the liquid film, as well as a prediction of the variation of the equilibrium vapor pressure variation with temperature and film thickness. Comparisons indicate that the predicted variations of vapor pressure with thickness for the three models are in close agreement. In addition, the density profile layering predicted by the MD simulations is in qualitative agreement with BGY results, however the exact density profile is dependent upon simulation parameters. Furthermore, the disjoining pressure effect predicted by MD simulations is strongly influenced by the allowable propagation time of injected molecules through the vapor region in the simulation domain. A modified thermodynamic model is developed that suggests that presence of a wall-affected layer tends to enhance the reduction of the equilibrium vapor pressure. However, the MD simulation results imply that presence of a wall layer has little effect on the vapor pressure. Implications of the MD simulation predictions for thin film transport in micro evaporators and heat pipes are also discussed.

Disjoining Pressure Effects in Ultra-Thin Liquid Films in Micropassages: Comparison of Thermodynamic Theory With Predictions of Molecular Dynamics Simulations

2005 ◽  
Author(s):  
V. P. Carey ◽  
A. P. Wemhoff
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Vapor Pressure ◽  
Film Thickness ◽  
Md Simulation ◽  
Heat Pipes ◽  
Md Simulations ◽  
Disjoining Pressure ◽  
Pressure Variation ◽  
Equilibrium Vapor Pressure

The concept of disjoining pressure, developed from thermodynamic and hydrodynamic analysis, has been widely used as a means of modeling the liquid-solid molecular force interactions in an ultra-thin liquid film on a solid surface. In particular, this approach has been extensively used in models of thin film transport in passages in micro evaporators and micro heat pipes. In this investigation, hybrid μPT molecular dynamics (MD) simulations were used to predict the pressure field and film thermophysics for an argon film on a metal surface. The results of the simulations are compared with predictions of the classic thermodynamic disjoining pressure model. The thermodynamic model provides only a prediction of the relation between vapor pressure and film thickness for a specified temperature. The MD simulations provide a detailed prediction of the density and pressure variation in the liquid film, as well as a prediction of the variation of the equilibrium vapor pressure variation with temperature and film thickness. Comparisons indicate that the predicted variations of vapor pressure with thickness for these two models are in close agreement. A modified thermodynamic model is developed which suggests that presence of a wall-affected layer tends to enhance the reduction of the equilibrium vapor pressure. However, the MD simulation results imply that presence of a wall layer has little effect on the vapor pressure. Implications of the MD simulation predictions for thin film transport in micro evaporators and heat pipes are also discussed.

Galvanomagnetic thin film devices

1967 ◽  
Vol 34 (2) ◽  
pp. 97 ◽  
Author(s):  
H. Freller ◽  
K.G. Günther
Keyword(s):  
Thin Film ◽  
Thin Film Devices
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