Nonlocal laser annealing to improve thermal contacts between multi-layer graphene and metals

Ермаков, В. А.; Alaferdov, Andrei V.; Vaz, Alfredo R.; Баранов, А. В.; Moshkalev, Stanislav A.

doi:10.1088/0957-4484/24/15/155301

Cited by 26 publications

(22 citation statements)

References 51 publications

(79 reference statements)

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“…Among them, the graphite/Ti has the highest K ⊥ , ∼120 MWm −2 K −1 , and the graphite/Au interface has the lowest K ⊥ , ∼30 MWm −2 K −1 near room temperature. Their K ⊥ of graphite/Au is consistent with the value by Norris et al and values of SLG/Au by Cai et al and FLG/Au by Ermakov et al Koh et al later measured heat flow across the Au/Ti/ n ‐LG/SiO 2 interfaces with the layer number n = 1 − 10. Their observed room‐temperature K ⊥ is ∼25 MWm −2 K −1 , which shows a very weak dependence on the layer number n and is equivalent to the total thermal conductance of Au/Ti/graphite and graphene/SiO 2 interfaces acting in series.…”

Section: Extrinsic Thermal Conductivity Of Graphenesupporting

confidence: 84%

“…The thermal interface conductance across graphene/graphite and other materials has been measured by using 3ω method, time‐domain thermoreflectance (TDTR) technique, and Raman‐based method, Most experimental data available to date are shown in Figure , and they are consistent with each other in general, given the variations of sample qualities and measurement techniques. Chen et al and Mak et al showed the thermal interface conductance per unit area of graphene/SiO 2 is K ⊥ ∼ 50 − 100 MWm −2 K −1 at room temperature, with no strong dependence on the FLG thickness.…”

Section: Extrinsic Thermal Conductivity Of Graphenementioning

confidence: 80%

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Thermal and Thermoelectric Properties of Graphene

Duan

2014

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The subject of thermal transport at the mesoscopic scale and in low-dimensional systems is interesting for both fundamental research and practical applications. As the first example of truly two-dimensional materials, graphene has exceptionally high thermal conductivity, and thus provides an ideal platform for the research. Here we review recent studies on thermal and thermoelectric properties of graphene, with an emphasis on experimental progresses. A general physical picture based on the Landauer transport formalism is introduced to understand underlying mechanisms. We show that the superior thermal conductivity of graphene is contributed not only by large ballistic thermal conductance but also by very long phonon mean free path (MFP). The long phonon MFP, explained by the low-dimensional nature and high sample purity of graphene, results in important isotope effects and size effects on thermal conduction. In terms of various scattering mechanisms in graphene, several approaches are suggested to control thermal conductivity. Among them, introducing rough boundaries and weakly-coupled interfaces are promising ways to suppress thermal conduction effectively. We also discuss the Seebeck effect of graphene. Graphene itself might not be a good thermoelectric material. However, the concepts developed by graphene research might be applied to improve thermoelectric performance of other materials.

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Section: Extrinsic Thermal Conductivity Of Graphenesupporting

confidence: 84%

Section: Extrinsic Thermal Conductivity Of Graphenementioning

confidence: 80%

Thermal and Thermoelectric Properties of Graphene

Duan

2014

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192

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“…Recently, we have observed 25 that MLG structures (that can be also called thin graphite nanoplatelets for thickness exceeding 10 monolayers 15 ) obtained by sonication of natural graphite demonstrate extremely high stability under heating by laser in air, with sample temperatures exceeding 1000 °C, i.e., under conditions when other graphitic materials including multi-walled carbon nanotubes (usually, more defective) are known to burn out very fast 26 27 .…”

mentioning

confidence: 99%

Burning Graphene Layer-by-Layer

Ермаков

Alaferdov

Vaz

et al. 2015

Sci Rep

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Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

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“…All FARMD simulations were carried out using the ReaxFF force field [3], as available in the Large-scale Atomic/Molecular Massive Parallel Simulator (LAMMPS) code [4]. In order to mimic the experimental conditions [2], our structural models consist of passivated multi-layer (6 layers) graphene, each layer with dimensions of 36x26 Å 2 (334 atoms). The multi-layer structure is placed on top of a rugous nickel substrate (size of 64x52x40 Å 3 , 5580 atoms); see Figure 2(a).…”

Section: Methodsmentioning

confidence: 99%

“…Layout of the experiment[2]. Graphene membranes are suspended over a metallic surfaces and laser beam irradiated.…”

mentioning

confidence: 99%

Improving Graphene-metal Contacts: Thermal Induced Polishing

et al. 2018

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Graphene is a very promising material for nanoelectronics applications due to its unique and remarkable electronic and thermal properties. However, when deposited on metallic electrodes the overall thermal conductivity is significantly decreased. This phenomenon has been attributed to the mismatch between the interfaces and contact thermal resistance. Experimentally, one way to improve the graphene/metal contact is thorough high-temperature annealing, but the detailed mechanisms behind these processes remain unclear. In order to address these questions, we carried out fully atomistic reactive molecular dynamics simulations using the ReaxFF force field to investigate the interactions between multi-layer graphene and metallic electrodes (nickel) under (thermal) annealing. Our results show that the annealing induces an upward-downward movement of the graphene layers, causing a piledriver-like effect over the metallic surface. This graphene induced movements cause a planarization (thermal polishing-like effect) of the metallic surface, which results in the increase of the effective graphene/metal contact area. This can also explain the experimentally observed improvements of the thermal and electric conductivities.

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Nonlocal laser annealing to improve thermal contacts between multi-layer graphene and metals

Cited by 26 publications

References 51 publications

Thermal and Thermoelectric Properties of Graphene

Thermal and Thermoelectric Properties of Graphene

Burning Graphene Layer-by-Layer

Improving Graphene-metal Contacts: Thermal Induced Polishing

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