Thermal conductivity of amorphous and crystalline thin films by molecular dynamics simulation

Huang, Zhengxing; Tang, Zhenan; Yu, Jun; Bai, Suyuan

doi:10.1016/j.physb.2009.02.022

Cited by 44 publications

(43 citation statements)

References 27 publications

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“…Interestingly, the aforementioned theory for macro bulk crystal material is applicable for the thermal conductivity evaluation in thin film crystal material based on our simulation results. In particular, the k 11 (5), which reveals a great agreement with our simulation result whose relative error is 4.6 %. It was worthy to note that the crystal orientation dependence of thermal conductivity has similar trend in bulk silica and nanometer thin film of silica.…”

Section: -supporting

confidence: 88%

“…10 Using molecular dynamics simulation, Huang et al investigated the size effect and the temperature dependence of thermal conductivity in crystalline SiO 2 films. 11,12 However, They selected the β-cristobalite as the crystalline SiO 2 models, which is not always the most stable structure within their calculated temperature range according to the phase diagram of silica. Colin 13 and Ratcliffe et al 14 measured the temperature dependence of thermal conductivity of crystal quartz by experimental technique.…”

Section: Introductionmentioning

confidence: 99%

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Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

Cao

Zhu

2017

AIP Advances

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In this work, the thermal properties of nanoscale SiO2 thin films have been systematically investigated with respect to the thickness, crystal orientations and the void defects using non-equilibrium molecular-dynamics (NEMD) simulation. Size effect for the lattice thermal conductivity of nanoscale SiO2 thin films was observed. Additionally, SiO2 thin films with [001] oriented exhibited greater thermal conductivity compared with other crystal orientations which was discussed in terms of phonon density of states (PDOS). Furthermore, the porosity of void defects was introduced to quantify the influence of defects for thermal conductivity. Results exhibited that the thermal conductivity degraded with the increase of porosity. Two thermal conductivity suppression mechanisms, namely, void defects induced material loss interdicting heat conduction and phonon scattering enhanced by the boundary of defects, were proposed. Then, a further simulation was deployed to find that the effect of boundary scattering of defects was dominant in thermal conductivity degradation compared with material loss mechanism. The conclusion suggests that the thermal conductivity could be configured via regulating the distribution of PDOS directly associated with void defects.

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Section: -supporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

Cao

Zhu

2017

AIP Advances

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“…This trend is in agreement with that predicted by others using MD simulation for films confined by two thermal reservoirs of the same species. [19][20][21][22][23] This difference suggests that the thermal transport in thin films depends not only on the species and thickness of the film but also on the materials that confine it.…”

Section: Temperature Profilesmentioning

confidence: 99%

“…16 Molecular dynamics ͑MD͒ simulations and lattice dynamics ͑LD͒ calculations can be used to study thermal transport in films in which the wavelike nature of the phonons is important. 11,[17][18][19][20][21][22][23] In a MD simulation, the positions and momenta of a set of atoms evolve classically according to Newton's equations of motion. Such simulations are an ideal method for predicting thermal transport properties because no assumptions concerning the phonon scattering within the film or at the film boundaries are required.…”

Section: Introductionmentioning

confidence: 99%

“…Previous MDbased studies used simulation cells that contained a film confined between two thermal reservoirs of the same species. [19][20][21][22][23] In these studies, the film thermal conductivity is predicted to increase toward the bulk value as the film thickness increases due to the decreasing effect of phonon scattering at the film/reservoir boundaries on the phonon mean free paths. Beyond obtaining predictions of the thermal conductivity, it is challenging to extract additional details related to the phonon transport from a MD simulation due to computational expense.…”

Section: Introductionmentioning

confidence: 99%

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Effect of film thickness on the thermal resistance of confined semiconductor thin films

Landry

McGaughey

2010

Journal of Applied Physics

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The thermal resistance of semiconductor thin films is predicted using lattice dynamics ͑LD͒ calculations and molecular dynamics ͑MD͒ simulations. We consider Si and Ge films with thicknesses, L F , between 0.2 and 30 nm that are confined between larger extents of the other species ͑i.e., Ge/Si/Ge and Si/Ge/Si structures͒. The LD predictions are made in the classical limit for comparison to the classical MD simulations, which are performed at a temperature of 500 K. For structures with L F Ͻ 2 nm, the thin film thermal resistance increases rapidly with increasing film thickness, a trend we attribute to changes in the allowed vibrational states in the film. These changes are found to affect the dependence of the phonon transmission coefficient on incidence angle

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Thermally induced increase in energy transport capacity of silkworm silks

Liu

Cao

et al. 2014

Biopolymers

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This work reports on the first study of thermally induced effect on energy transport in single filaments of silkworm (Bombyx mori) fibroin degummed mild (type 1), moderate (type 2), to strong (type 3). After heat treatment from 140 to 220°C, the thermal diffusivity of silk fibroin type 1, 2, and 3 increases up to 37.9, 20.9, and 21.5%, respectively. Our detailed scanning electron microscopy study confirms that the sample diameter change is almost negligible before and after heat treatment. Raman analysis is performed on the original and heat-treated (at 147°C) samples. After heat treatment at 147°C, the Raman peaks at 1081, 1230, and 1665 cm(-1) become stronger and narrower, indicating structural transformation from amorphous to crystalline. A structure model composed of amorphous, crystalline, and laterally ordered regions is proposed to explain the structural change by heat treatment. Owing to the close packing of more adjacent laterally ordered regions, the number and size of the crystalline regions of Bombyx mori silk fibroin increase by heat treatment. This structure change gives the observed significant thermal diffusivity increase by heat treatment.

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Thermal conductivity of amorphous and crystalline thin films by molecular dynamics simulation

Cited by 44 publications

References 27 publications

Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

Effect of film thickness on the thermal resistance of confined semiconductor thin films

Thermally induced increase in energy transport capacity of silkworm silks

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