Study of thermal properties of graphene-based structures using the force constant method

Karamitaheri, Hossein; Neophytou, Neophytos; Pourfath, Mahdi; Kosina, H.

doi:10.1007/s10825-011-0380-9

Cited by 20 publications

(20 citation statements)

References 54 publications

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“…This means that 2D graphene and its multilayer counterparts are useful for thermal management applications [21]. The high thermal conductivity of the graphene is mainly due to the high phonon contribution to heat transport.…”

Section: Resultsmentioning

confidence: 99%

Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

Sadeghi¹,

Sangtarash²,

Lambert³

2015

Beilstein J. Nanotechnol.

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SummaryWe demonstrate that thermoelectric properties of graphene nanoribbons can be dramatically improved by introducing nanopores. In monolayer graphene, this increases the electronic thermoelectric figure of merit ZT e from 0.01 to 0.5. The largest values of ZT e are found when a nanopore is introduced into bilayer graphene, such that the current flows from one layer to the other via the inner surface of the pore, for which values as high as ZT e = 2.45 are obtained. All thermoelectric properties can be further enhanced by tuning the Fermi energy of the leads.

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Section: Resultsmentioning

confidence: 99%

Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

Sadeghi¹,

Sangtarash²,

Lambert³

2015

Beilstein J. Nanotechnol.

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“…Under the harmonic approximation, the motion of atoms can be described by a dynamic matrix as [15]: (2) where dynamic matrix component between atoms 'i' and 'j' is given as shown in Ref. [14] by: After setting up the dynamic matrix, the following eigenvalue problem is solved to calculate the phononic dispersion:…”

mentioning

confidence: 99%

“…where l D is the dynamic matrix representing the interaction between the unit cell and its neighboring unit cells separated by l R [15]. Using the phononic dispersion, the density of states (DOS) and the ballistic transmission (number of modes at given energy) are calculated as shown in Ref.…”

mentioning

confidence: 99%

Calculation of Confined Phonon Spectrum in Narrow Silicon Nanowires Using the Valence Force Field Method

Karamitaheri

Neophytou

Taheri

et al. 2013

Journal of Elec Materi

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We study the effect of confinement on the phonon properties of ultra-narrow silicon nanowires of side sizes of 1 10nm . We use the modified valence force field method to compute the phononic dispersion, and extract the density of states, the transmission function, the sound velocity, the ballistic thermal conductance and boundary scatteringlimited diffusive thermal conductivity. We find that the phononic dispersion and the ballistic thermal conductance are functions of the geometrical features of the structures, i.e. the transport orientation and confinement dimension. The phonon group velocity and thermal conductance can vary by a factor of two depending on the geometrical features of the channel. The <110> nanowire has the highest group velocity and thermal conductance, whereas the <111> the lowest. The <111> channel is thus the most suitable orientation for thermoelectric devices based on Si nanowires since it also has a large power factor. Our findings could be useful in the thermal transport design of siliconbased devices for thermoelectric and thermal management applications.

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“…is the second derivative of the potential energy (U ) after atoms 'i' and 'j' are slightly displaced along the m-axis and For setting up the dynamical matrix component between the i th and the j th carbon atoms, which are the N th nearestneighbors of each other, we use the force constant method (FCM), involving interactions up to the fourth nearestneighbor [54,55]. The force constant tensor is given by:…”

Section: Methodsmentioning

confidence: 99%