Interfacial properties and morphologies of graphene-graphane composite sheets

Reddy, C. D.; Cheng, Qiang; Shenoy, Vivek B.; Zhang, Yong‐Wei

doi:10.1063/1.3555612

Cited by 27 publications

(16 citation statements)

References 25 publications

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“…13,24 Meanwhile, interfacial strain due to partial hydrogenation can affect the morphologies of HGSs. 25 It is predicted such interfacial strain would also have an effect on their thermal properties. Therefore, this study aims to understand the effect of the hydrogenation style and hydrogen coverage on the morphology and k of HGSs via molecular dynamics (MD) simulations.…”

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confidence: 99%

“…Due to hydrogenation, it is found that the lattice parameter of the GA, GO, and RGO sheets is increased by around 5%, which is in good agreement with previous studies. 25,33 Hence, the hydrogenation induces interfacial strain between GA (GO/RGO) and GE strips, leading to the warping of the HGSs, a phenomenon similar to the warping of pure GE sheets induced by their compressive edge stress. [34][35][36] Mechanical and physical properties of a GE sheet strongly depend on its structure, particularly its morphology.…”

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confidence: 99%

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Morphology and in-plane thermal conductivity of hybrid graphene sheets

Liu

Reddy

Jiang

et al. 2012

Applied Physics Letters

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This paper investigates the morphology and in-plane thermal conductivity of hybrid graphene sheets (HGSs), which consist of un-hydrogenated and single-side or double-side hydrogenated strips, via molecular dynamics simulation. The study shows that the hydrogenation styles and hydrogen coverage significantly affect the morphology and thermal conductivity of HGSs. The thermal conductivity of HGSs decreases dramatically, compared to that of pure graphene sheets, and the magnitude falls in the range of 30%-75%. Such differences are explained by conducting the phonon spectra analysis. V C 2012 American Institute of Physics. [http://dx.

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confidence: 99%

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confidence: 99%

Morphology and in-plane thermal conductivity of hybrid graphene sheets

Liu

Reddy

Jiang

et al. 2012

Applied Physics Letters

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“…The bond length and lattice constant (the second-nearest-neighbor distance) of GE are 1.42 and 2.46 Å, respectively. Due to hydrogenation, it is found that the lattice parameter of the GA, GO and RGO sheets are increased by around 5%, which is in good agreements with previous studies [100,106]. Hence, the hydrogenation induces interfacial strain between GA (GO/RGO) and GE strips, leading to the warping of the HGSs, a phenomenon similar to the warping of pure GE sheets induced by their compressive edge stress [107,108].…”

Section: Morphologysupporting

confidence: 88%

“…On the other hand, external elastic strain applied to GE-based materials has been found to alter their thermal properties by changing their morphologies [66,99]. Meanwhile, interfacial strain due to partial hydrogenation can affect the morphologies of HGSs [100]. It is predicted such interfacial strain would also have an effect on their thermal properties.…”

Section: Ge Hydrogenationmentioning

confidence: 99%

Thermal properties of two-dimensional nanomaterials

Liu¹

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Two-dimensional (2D) nanomaterials have attracted intensive interest in the past decades owing to their superior properties and prospective applications in nanodevices. Recently, there is an increasing demand for understanding the thermal properties of these nanomaterials. This demand is driven by the fact that thermal dissipation at the nanoscale has become a crucial issue because of the ever continuing miniaturization of nanodevices. In addition, thermal transport in nanomaterials has revealed many unique phenomena, of which the understanding would lead to novel nanotechnologies in thermal management. Most of these unique phenomena are related to an important characteristic of nanomaterial: their properties highly depend on their atomic structures which are often inevitably altered by chemical functionalization, strain and presence of structural interruptions induced during fabrication or application. Hence, this PhD study has been devoted to studying the thermal properties of 2D nanomaterials and understanding the structural alteration effects through the method of non-equilibrium molecular dynamics simulation. Three representative types of such 2D nanomaterials, namely, graphene (GE), silicene (SE) and MoS 2 have been investigated. As one of the important chemical functionalization methods, hydrogenation has been widely used to tune the properties of nanomaterials and obtain their derivative counterparts. The simulation results have revealed that the thermal conductivity of hydrogenated GE is much lower than that of pristine GE and highly depends on both the hydrogen coverage and hydrogenation pattern. The two distinct mechanisms of phononinterface and phonon-phonon scatterings were identified to be responsible for the low

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“…We also show that with a small perturbation at the edge is possible to lift the degeneracy between interfaces, allowing a single-interface conduction. The electronic structure simulations were performed within the density functional theory.As in graphane [22], a completely hydrogenated graphene, we can built a germanene nanoroad by removing the hydrogen atoms [23][24][25][26][27] in a desired pattern by, for example, hydrogen dissociation via plasma etching. This germanene structure inside germanane is a non-trivial topological insulator embedded in a trivial insulator and from the bulk-edge correspondence, gapless topological edge states should appear on this lineinterface region.…”

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Quantum spin Hall effect on germanene nanorod embedded in completely hydrogenated germanene

2014

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We show that germanene nanoroads embedded in a completely hydrogenated germanene (germanane) exhibits a Quantum Spin Hall Effect (QSHE). These nanoroads can be obtained experimentally by local hydrogen dissociation from germanane. Using first principle calculations we predict that germanene nanoroads with zigzag interfaces show dissipationless conducting channels with in-plane and out-of-plane spin textures.The search for topological quantum phases of matter led condensed matter scientists to inspect, under a different point of view, materials known as Topological Insulators (TI). Those materials exhibit different properties and physical phenomena, like the quantum spin Hall effect (QSHE) [1], axion electrodynamics [2] and Majorana fermions [3]. The QSHE in two dimensional (2D) materials was proposed by Kane and Mele for graphene [1], followed by an independent proposal by Bernevig, Hughes and Zhang for the CdTe/HgTe/CdTe quantum well [4]. The latter has been confirmed experimentally [5], but for graphene due to the small spin-orbit bandgap, the observation of the QSHE would apply only at unaffordable experimental conditions [6,7].New candidate materials has been proposed to overcome the issue presented by graphene for the observation of the QSHE. Among some of these materials are the silicene [8][9][10][11][12][13], germanene [14], 2D hexagonal Si x Ge 1−x [15], and stanene [16]. They present similar properties to graphene, having some additional features, such as: (i) buckled honeycomb lattice; (ii) relatively large spin-orbit coupling (SOC), with bandgap of the order of meV and topological invariant Z 2 = 1 [14,15]. Such characteristics makes these 2D TI good candidates for the observation of the QSHE.From the experimental point of view, the pursuit of 2D materials that could display the QSHE was intensified by the synthesization of silicene. Silicene is mostly grown on metal surfaces, [8][9][10][11][12][17][18][19][20] that introduces some difficulties to isolate this single layer material and construct devices that will allow the measurement of the QSHE. Also the SOC bandgap in silicene is small, around 1.9 meV, so that the temperature to observe the QSHE will also be very low.A recent work of Bianco et al.[21] reported synthesis of germanane, a completely hydrogenated germanene structure. This opens up a new route to the experimental observation of the QSHE at higher temperatures. The formation and stability of this material, as well as the study of the QSHE may play an important role in nanoelectronics [21].In this work we propose a feasible setup for the observation of QSHE that is based on germanane [21]. The system is a germanene nanoroad embedded in germanane. We find that the germanene nanoroads with zigzag interfaces presents dissipationless conducting channels with in-plane and out-of-plane spin texture. We also show that with a small perturbation at the edge is possible to lift the degeneracy between interfaces, allowing a single-interface conduction. The electronic structure simulations were perf...

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Interfacial properties and morphologies of graphene-graphane composite sheets

Cited by 27 publications

References 25 publications

Morphology and in-plane thermal conductivity of hybrid graphene sheets

Morphology and in-plane thermal conductivity of hybrid graphene sheets

Thermal properties of two-dimensional nanomaterials

Quantum spin Hall effect on germanene nanorod embedded in completely hydrogenated germanene

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