Suppression of thermal conductivity in graphene nanoribbons with rough edges

Savin, A. V.; Kivshar, Yuri S.; Hu, Bambi

doi:10.1103/physrevb.82.195422

Cited by 204 publications

(165 citation statements)

References 32 publications

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“…24 Several ways to reduce the thermal conductivity have already been examined, such as interface mismatching between graphene and nanoribbons, 25,26 the presence of isotopes, [27][28][29][30] cross-plane phonon coupling in a few layers of graphene, 31 strain, 32 random hydrogen vacancies in graphene, 33 and point defects. [34][35][36] Edge disorder has been predicted theoretically to suppress heat conductance of graphene nanoribbons, [37][38][39] and ZT exceeding 3 has been theoretically predicted for such systems in the diffusive limit. 40 GALs have been proposed as a flexible platform for creating a semiconducting material with a band gap which can be tuned by varying the antidot size, shape, or lattice symmetry.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of finite graphene antidot lattices

et al. 2011

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We present calculations of the electronic and thermal transport properties of graphene antidot lattices with a finite length along the transport direction. The calculations are based on a single orbital tight-binding model and the Brenner potential. We show that both electronic and thermal transport properties converge fast toward the bulk limit with increasing length of the lattice: only a few repetitions (~6) of the fundamental unit cell are required to recover the electronic band gap of the infinite lattice as a transport gap for the finite lattice. We investigate how different antidot shapes and sizes affect the thermoelectric properties. The resulting thermoelectric figure of merit, ZT, can exceed 0.25, and it is highly sensitive to the atomic arrangement of the antidot edges. Specifically, hexagonal holes with pure zigzag edges lead to an order-of-magnitude smaller ZT as compared to pure armchair edges. We explain this behavior as a consequence of the localization of states, which predominantly occurs for zigzag edges, and of an increased splitting of the electronic minibands, which reduces the power factor.Comment: 12 pages, 13 figures. Submitted to Phys. Rev.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of finite graphene antidot lattices

et al. 2011

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“…The major effect in limiting thermal conductivity in 1D channels, however, seems to be boundary scattering [24,61,9]. Two orders of magnitude reduction in thermal conductivity has been reported for several low-dimensional materials due to roughness compared to the pristine materials, which significantly improve their thermoelectric properties [61,62,14].…”

Section: Introductionmentioning

confidence: 99%

“…Several works have shown that the transports properties of low-dimensional systems are significantly degraded by the introduction of scattering centers and localized states [9,10,22,14,23,24,25]. In the case of electronic transport, even a small degree of disorder can drastically reduce the electronic conductivity (especially in AGNRs rather than ZGNRs), even driving carriers into the localization regime and introduce 'effective' transmission bandgaps [15,26,27,28].…”

Section: Introductionmentioning

confidence: 99%

“…Graphene nanoribbons (GNR) are onedimensional structures that have attracted significant attention, both for fundamental research as well as for technological applications [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. Ultra-narrow GNRs have been shown to retain at some degree the remarkable thermal properties of graphene.…”

Section: Introductionmentioning

confidence: 99%

“…However, the presence of edges can result in geometry dependent properties. The width, chirality, and the magnitude of edge disorder of the GNR, can strongly determine its electronic [15,16,17,18] and heat transport properties [9,10,19,20,21].…”

Section: Introductionmentioning

confidence: 99%

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Low-dimensional phonon transport effects in ultranarrow disordered graphene nanoribbons

et al. 2015

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We investigate the influence of low-dimensionality and disorder in phonon transport in ultra-narrow armchair graphene nanoribbons (GNRs) using non-equilibrium Green's function (NEGF) simulation techniques. We specifically focus on how different parts of the phonon spectrum are influenced by geometrical confinement and line edge roughness. Under ballistic conditions, phonons throughout the entire phonon energy spectrum contribute to thermal transport. With the introduction of line edge roughness, the phonon transmission is reduced, but in a manner which is significantly non-uniform throughout the spectrum. We identify four distinct behaviors within the phonon spectrum in the presence of disorder: i) the low-energy, low-wavevector acoustic branches have very long mean-free-paths and are affected the least by edge disorder, even in the case of ultra-narrow W=1nm wide GNRs; ii) energy regions that consist of a dense population of relatively 'flat' phonon modes (including the optical branches) are also not significantly affected, except in the case of the ultra-narrow W=1nm GNRs, in which case the transmission is reduced because of band mismatch along the phonon transport path; iii) 'quasi-acoustic' bands that lie within the intermediate region of the spectrum are strongly affected by disorder as this part of the spectrum is depleted of propagating phonon modes upon both confinement and disorder (resulting in sparse E(q) phononic bandstructure), especially as the channel length increases; iv) the strongest reduction in phonon transmission is observed in energy regions that are composed of a small density of phonon modes, in which case roughness can introduce transport gaps that greatly increase with channel length. We show that in GNRs of widths as small as W=3nm, under moderate roughness, both the low-energy acoustic modes and dense regions of optical modes can retain semi-ballistic transport properties, even for channel lengths up to 2 L=1μm. These modes tend to completely dominate thermal transport. Modes in the sparse regions of the spectrum, however, tend to fall into the localization regime, even for channel lengths as short as 10s of nanometers, despite their relatively high phonon group velocities.

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High Thermal Conductivity 2D Materials: From Theory and Engineering to Applications

Tian

Shen

et al. 2022

Adv Materials Inter

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The channel/gate length of transistors is getting close to the physical limit. [1] To meet the requirements of chip performance, advanced design technologies are utilized to bring higher Transistors are getting close to their physical limitation, and complex chip design technologies have made the hotspot problem more serious. Graphene and hBN, as representative 2D semi-metal and dielectric materials, possess excellent thermal conductivities. Intrinsic 2D materials, 2D film materials, and 2D composite materials have been investigated, showing great potential for next-generation thermal-management materials. There are products that have already been commercialized based on graphene and hBN, but many companies seem to be sitting on the fence, and the obstacles toward implementation of these materials need to be specified. Here, high thermal conductivity 2D materials from theory and engineering to applications are reviewed, aiming to provide a comprehensive summary of the current state of the art of this field in order to give an overview and future prospects in application, manufacturing, and commercialization. From the theoretical perspective, the impact factors and development path of 2D materials for thermal dissipation and the engineering aspect of structural design are presented. The prospects and challenges are also tackled, expressing an objective view about future opportunities to build 2D-based heat-dissipation systems.

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Suppression of thermal conductivity in graphene nanoribbons with rough edges

Cited by 204 publications

References 32 publications

Thermoelectric properties of finite graphene antidot lattices

Thermoelectric properties of finite graphene antidot lattices

Low-dimensional phonon transport effects in ultranarrow disordered graphene nanoribbons

High Thermal Conductivity 2D Materials: From Theory and Engineering to Applications

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