Monte Carlo simulation of thermal conductivity of Si nanowire: An investigation on the phonon confinement effect on the thermal transport

2012 ◽  
Vol 112 (7) ◽  
pp. 074323 ◽  
Author(s):  
Chandan Bera
Keyword(s):  
Thermal Conductivity ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Thermal Transport ◽  
Confinement Effect ◽  
Phonon Confinement ◽  
Si Nanowire ◽  
Phonon Confinement Effect

Thermal Conductivity in Thin Silicon Nanowires:  Phonon Confinement Effect

Nano Letters ◽  
2007 ◽  
Vol 7 (5) ◽  
pp. 1155-1159 ◽  
Author(s):  
Inna Ponomareva ◽  
Deepak Srivastava ◽  
Madhu Menon
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nanowires ◽  
Confinement Effect ◽  
Phonon Confinement ◽  
Thin Silicon ◽  
Phonon Confinement Effect

Monte Carlo Simulation of Thermal Conductivities of Silicon Nanowires

2005 ◽  
Author(s):  
Yunfei Chen ◽  
Deyu Li ◽  
Jennifer R. Lukes ◽  
Zhonghua Ni
Keyword(s):  
Thermal Conductivity ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Dispersion Relation ◽  
Thermal Transport ◽  
Phonon Transport ◽  
Si Nanowires ◽  
Nanowire Diameter ◽  
Energy Conversion Devices ◽  
Tens Nanometer

One-dimensional (1D) materials such as various kinds of nanowires and nanotubes have attracted considerable attention due to their potential applications in electronic and energy conversion devices. The thermal transport phenomena in these nanowires and nanotubes could be significantly different from that in bulk material due to boundary scattering, phonon dispersion relation change, and quantum confinement. It is very important to understand the thermal transport phenomena in these materials so that we can apply them in the thermal design of microelectronic, photonic, and energy conversion devices. While intensive experimental efforts are being carried out to investigate the thermal transport in nanowires and nanotube, an accurate numerical prediction can help the understanding of phonon scattering mechanisms, which is of fundamental theoretical significance. A Monte Carlo simulation was developed and applied to investigate phonon transport in single crystalline Si nanowires. The Phonon-phonon Normal (N) and Umklapp (U) scattering processes were modeled with a genetic algorithm to satisfy both the energy and the momentum conservation. The scattering rates of N and U scattering processes were given from the first perturbation theory. Ballistic phonon transport was modeled with the code and the numerical results fit the theoretical prediction very well. The thermal conductivity of bulk Si was then simulated and good agreement was achieved with the experimental data. Si nanowire thermal conductivity was then studied and compared with some recent experimental results. In order to study the confinement effects on phonon transport in nanowires, two different phonon dispersions, one based on bulk Si and the other solved from the elastic wave theory for nanowires, were adopted in the simulation. The discrepancy from the simulations based on different phonon dispersions increases as the nanowire diameter decreases, which suggests that the confinement effect is significant when the nanowire diameter goes down to tens nanometer range. It was found that the U scattering probability engaged in Si nanowires was increased from that in bulk Si due to the decrease of the frequency gap between different modes and the reduced phonon group velocity. Simulation results suggest that the dispersion relation for nanowire solved from the elasticity theory should be used to evaluate nanowire thermal conductivity as the nanowire diameter reduced to tens nanometer.

LATTICE THERMAL CONDUCTIVITY IN A HOLLOW SILICON NANOWIRE

2005 ◽  
Vol 19 (06) ◽  
pp. 1017-1027 ◽  
Author(s):  
WEI-QING HUANG ◽  
KE-QIU CHEN ◽  
Z. SHUAI ◽  
LINGLING WANG ◽  
WANGYU HU
Keyword(s):  
Thermal Conductivity ◽  
Relaxation Time ◽  
Lattice Thermal Conductivity ◽  
Silicon Nanowire ◽  
Boundary Scattering ◽  
Phonon Confinement ◽  
Time Approximation ◽  
Si Nanowire ◽  
Scattering Mechanisms ◽  
Relaxation Time Approximation

We theoretically investigate the lattice thermal conductivity of a hollow Si nanowire under the relaxation time approximation. The results show that the thermal conductivity in such structure is decreased markedly below the bulk value due to phonon confinement and boundary scattering. The thermal conductivities under different scattering mechanisms are given, and it is found that the boundary scattering is dominant resistive process for the decrease of the thermal conductivity.

The negative phonon confinement effect in nanoscopic sodium nitrite

2009 ◽  
Vol 20 (39) ◽  
pp. 395706 ◽  
Author(s):  
E Yu Koroleva ◽  
D Nuzhnyy ◽  
J Pokorny ◽  
S Kamba ◽  
Yu A Kumzerov ◽  
...  
Keyword(s):  
Sodium Nitrite ◽  
Confinement Effect ◽  
Phonon Confinement ◽  
Phonon Confinement Effect

scholarly journals Thermal transport in nanocrystalline Si and SiGe by ab initio based Monte Carlo simulation

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lina Yang ◽  
Austin J. Minnich
Keyword(s):  
Thermal Conductivity ◽  
Monte Carlo ◽  
Ab Initio ◽  
Grain Boundaries ◽  
Thermal Transport ◽  
Phonon Scattering ◽  
Phonon Dispersion ◽  
Computational Study ◽  
Phonon Transport ◽  
Nanocrystalline Si

Abstract Nanocrystalline thermoelectric materials based on Si have long been of interest because Si is earth-abundant, inexpensive, and non-toxic. However, a poor understanding of phonon grain boundary scattering and its effect on thermal conductivity has impeded efforts to improve the thermoelectric figure of merit. Here, we report an ab-initio based computational study of thermal transport in nanocrystalline Si-based materials using a variance-reduced Monte Carlo method with the full phonon dispersion and intrinsic lifetimes from first-principles as input. By fitting the transmission profile of grain boundaries, we obtain excellent agreement with experimental thermal conductivity of nanocrystalline Si [Wang et al. Nano Letters 11, 2206 (2011)]. Based on these calculations, we examine phonon transport in nanocrystalline SiGe alloys with ab-initio electron-phonon scattering rates. Our calculations show that low energy phonons still transport substantial amounts of heat in these materials, despite scattering by electron-phonon interactions, due to the high transmission of phonons at grain boundaries, and thus improvements in ZT are still possible by disrupting these modes. This work demonstrates the important insights into phonon transport that can be obtained using ab-initio based Monte Carlo simulations in complex nanostructured materials.

Formation, structure, and phonon confinement effect of nanocrystalline Si1−xGex in SiO2‐Si‐Ge cosputtered films

2004 ◽  
Vol 96 (9) ◽  
pp. 5239-5242 ◽  
Author(s):  
Y. M. Yang ◽  
X. L. Wu ◽  
G. G. Siu ◽  
G. S. Huang ◽  
J. C. Shen ◽  
...  
Keyword(s):  
Confinement Effect ◽  
Phonon Confinement ◽  
Phonon Confinement Effect

Phonon confinement effect on nanocrystalline LiCoO2 studied with Raman spectroscopy

2008 ◽  
Vol 69 (11) ◽  
pp. 2911-2915 ◽  
Author(s):  
M. Okubo ◽  
E. Hosono ◽  
T. Kudo ◽  
H.S. Zhou ◽  
I. Honma
Keyword(s):  
Raman Spectroscopy ◽  
Confinement Effect ◽  
Phonon Confinement ◽  
Phonon Confinement Effect
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