Investigating the thermal transport in gold decorated graphene by Opto-thermal Raman technique

2021 ◽  
Author(s):  
Ranjuna M K ◽  
Jayakumar Balakrishnan
Keyword(s):  
Thermal Conductivity ◽  
Gold Nanoparticles ◽  
Thermal Management ◽  
Thermal Transport ◽  
Thermal Conductance ◽  
Single Layer ◽  
Thermal Conversion ◽  
Single Layer Graphene ◽  
Phonon Coupling ◽  
Au Nps

Abstract We report a systematic study on the thermal transport properties of gold nanoparticles (Au NPs) decorated single-layer graphene (SLG) on a SiO2/Si substrate by the Opto-thermal Raman technique. Our results, with moderate Au NPs coverage( <10%), demonstrate an enhancement in the thermal conductivity of graphene by ~ 55% from its pristine value and a decrement in the interface conductance by a factor of 1.5. A detailed analysis of our results shows the importance of the photo-thermal conversion efficiency of Au NPs, plasmon-phonon coupling and lattice modifications in the graphene developed after gold nanoparticles deposition in enhancing the thermal conductivity and reducing the interface thermal conductance of the system. Our study paves way for a better understanding of the thermal management in such hybrid systems, which are envisioned as excellent candidates for optoelectronics and photonics applications.

Thermal Conductivity of Phonon Modes in Graphene Nanoribbon at Localized High Heating

2015 ◽  
Author(s):  
Tatiana Zolotoukhina
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Single Layer ◽  
Phonon Transport ◽  
Graphene Nanoribbon ◽  
Single Layer Graphene ◽  
Quasi Equilibrium ◽  
Phonon Modes ◽  
Limited Region ◽  
Small Areas

The spectral components of the phonon transport in the locally thermally excited graphene samples were studied by molecular dynamics (MD) method. In order to be able to select and analyze separate phonon modes in the time of propagation, the transient Green-Kubo approach to the definitions of density of states (DOS) and thermal conductivity was tested in quasi-equilibrium regimes for limited region of the graphene sample studied. Propagation of single modes at the background of diffusional phonon distribution and energy decay of such modes are studied by calculation of the DOS and dispersion relations, their dependence on the heating condition and temperature is studied. Similar conditions can be generated at localized heating of small areas of graphene structures in electronic devices. In transient regime, many issues of thermal transport evaluation still remain not sufficiently tested, especially phonon dynamics. Thermal conductivity of graphene samples related to transport of separate phonon modes is still not completely investigated, however, recent result give indication on the difference in the contribution of phonon modes. In the study, we consider mostly high temperature transport modes that are generated at the heated spot in order to be able to define their velocities and lifetimes in the limit of transient MD sampling. The single-layer graphene nanoribbon of 150 nm to 40 nm was relaxed and prepared in equilibrium in zigzag and armchair orientations. REBO potential for graphene was utilized. Our calculation has shown that at the heating to high temperatures of 1000K and higher, the G mode of graphene remains stationary and has a minimal contribution into thermal transport by coherent modes. The coherent phonon mode or modes that contribute the most into thermal transport were confined in the vicinity of 30 THz and can possibly be attributed to the D modes of graphene.

Thermal Transport at Carbon Nanotube-Graphene Junction

2013 ◽  
Author(s):  
Jungkyu Park ◽  
Vikas Prakash
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Thermal Resistance ◽  
Thermal Transport ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Interfacial Thermal Resistance ◽  
Interfacial Resistance ◽  
Pillar Height

We present results of a molecular dynamics study to analyze thermal transport at carbon nanotube (CNT)-graphene junctions comprising of single layer graphene and (6,6) armchair single-walled carbon nanotubes (SWCNTs). Two possible junction types with different degrees of sp2 and sp3 hybridization are investigated. Reverse Non-Equilibrium Molecular Dynamics (RNEMD) simulations are used to obtain the thermal conductivities in these hybrid structures and also analyze the role of the interfacial thermal resistance at the SWCNT-graphene junctions in limiting thermal transport. The highest out-of-plane (along the SWCNT axis) thermal conductivity of a hybrid structure with a CNT-graphene junction was obtained to be 158.9±1.2 W/m-K when the junction comprised of only sp2 bonds with an interpillar distance of 15 nm and a pillar height of 200 nm. The highest in-plane thermal conductivity (along the graphene layer plane) with two CNT-graphene junctions was found to be 392.2±9.9 W/m-K with junctions comprising of only sp2 bonds and an interpillar distance of 20 nm and a pillar height of 25 nm. In all cases, junctions with mixed sp2/sp3 hybridization showed higher interfacial thermal resistance than junctions with pure sp2 bonds, and the thermal interfacial resistance was found to be weakly dependent on the length of CNT and the interpillar distance. The highest interfacial thermal resistance measured across the CNT-graphene junction was 3.10×10−6 K-cm2/W when the junction comprised of mixed sp2/sp3 bonds and with 15 nm interpillar distance and 50 nm pillar height.

Thermal Conductivity Reduction in Few-Layer Graphene

2011 ◽  
Author(s):  
Dhruv Singh ◽  
Jayathi Y. Murthy ◽  
Timothy S. Fisher
Keyword(s):  
Thermal Conductivity ◽  
Weak Coupling ◽  
Phonon Scattering ◽  
Single Layer ◽  
Acoustic Mode ◽  
Single Layer Graphene ◽  
Boltzmann Transport ◽  
Layer Graphene ◽  
Out Of Plane ◽  
Few Layer Graphene

Using the linearized Boltzmann transport equation and perturbation theory, we analyze the reduction in the intrinsic thermal conductivity of few-layer graphene sheets accounting for all possible three-phonon scattering events. Even with weak coupling between layers, a significant reduction in the thermal conductivity of the out-of-plane acoustic modes is apparent. The main effect of this weak coupling is to open many new three-phonon scattering channels that are otherwise absent in graphene. The highly restrictive selection rule that leads to a high thermal conductivity of ZA phonons in single-layer graphene is only weakly broken with the addition of multiple layers, and ZA phonons still dominate thermal conductivity. We also find that the decrease in thermal conductivity is mainly caused by decreased contributions of the higher-order overtones of the fundamental out-of-plane acoustic mode. Moreover, the extent of reduction is largest when going from single to bilayer graphene and saturates for four layers. The results compare remarkably well over the entire temperature range with measurements of of graphene and graphite.

Raman scattering and tunable electron–phonon coupling in single layer graphene

2007 ◽  
Vol 143 (1-2) ◽  
pp. 39-43 ◽  
Author(s):  
Jun Yan ◽  
Yuanbo Zhang ◽  
Sarah Goler ◽  
Philip Kim ◽  
Aron Pinczuk
Keyword(s):  
Raman Scattering ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Phonon Coupling ◽  
Layer Graphene ◽  
Electron Phonon Coupling

Mode dependent lattice thermal conductivity of single layer graphene

2014 ◽  
Vol 116 (15) ◽  
pp. 153503 ◽  
Author(s):  
Zhiyong Wei ◽  
Juekuan Yang ◽  
Kedong Bi ◽  
Yunfei Chen
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene

Substrate Effects on the Thermal Conductivity of Single Layer Supported Graphene

2011 ◽  
Author(s):  
Z. Wei ◽  
C. Dames ◽  
Y. Chen
Keyword(s):  
Thermal Conductivity ◽  
Silicon Dioxide ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Dynamics Model ◽  
Graphene Flake ◽  
Substrate Effects ◽  
Layer Graphene ◽  
Lennard Jones ◽  
Non Equilibrium Molecular Dynamics

A non-equilibrium molecular dynamics model is developed to calculate the thermal conductivity of single layer graphene supported on silicon dioxide. We use the Tersoff potential to describe the carbon-carbon interactions within graphene, and a Lennard-Jones (LJ) potential to describe the interactions between graphene and silicon dioxide. To overcome possible artifacts of thermal expansion, the model avoids using any periodic or fixed boundary conditions for the graphene flake. For both smooth and rough substrates, the simulations show that increasing the LJ coupling strength between graphene and substrate can reduce the in-plane thermal conductivity of graphene. We also investigated the effects of roughness. The simulations show that the thermal conductivity is sensitive to the roughness only when the coupling is large. These results indicate how the thermal properties of graphene may be modified by adjusting the coupling and roughness of the substrate.

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