Electron and phonon transport in silicon nanowires: Atomistic approach to thermoelectric properties

Markussen, Troels; Jauho, Antti–Pekka; Brandbyge, Mads

doi:10.1103/physrevb.79.035415

Cited by 188 publications

(171 citation statements)

References 32 publications

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“…7 The hole and electron transmission characteristics have been determined for pristine NWs and NWs that contain dopants and vacancies by the Kubo method, recursive Green's function method, and tight binding approaches. [23][24][25][26] Ge NWs have similar properties to Si NWs and it has been shown that Ge vacancies reduce the thermal conductivity. The transmission coefficients of Si NWs with vacancies have been obtained by the nonequilibrium Green's function method.…”

Section: Introductionmentioning

confidence: 99%

Structural and tunneling properties of Si nanowires

et al. 2013

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We investigate the electronic structure and electron transport properties of Si nanowires attached to Au electrodes from first principles using density functional theory and the nonequilibrium Green's function method. We systematically study the dependence of the transport properties on the diameter of the nanowires, on the growth direction, and on the length. At the equilibrium Au-nanowire distance we find strong electronic coupling between the electrodes and nanowires, which results in a low contact resistance. With increasing nanowire length we study the transition from metallic to tunneling conductance for small applied bias. For the tunneling regime we investigate the decay of the conductance with the nanowire length and rationalize the results using the complex band structure of the pristine nanowires. The conductance is found to depend strongly on the growth direction, with nanowires grown along the 110 direction showing the smallest decay with length and the largest conductance and current.

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Section: Introductionmentioning

confidence: 99%

Structural and tunneling properties of Si nanowires

et al. 2013

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“…The self-energies L,R are iteratively constructed from the semi-infinite graphene left (L) and right (R) leads. The calculation of both electron and phonon k-averaged Landauer transmissions together with the thermoelectric properties are performed by an atomistic Green's function method, 16,62 …”

Section: A Methodsmentioning

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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“…Measurement techniques have evolved to the point where they can provide a deep insight into the thermal conduction of nanowires 10,11 , which is essential for both electronic and thermoelectric applications. A the same time the theoretical understanding of the thermal properties of nanowires has kept improving due to the development of always complexer and more accurate models [12][13][14][15][16][17][18][19][20][21][22][23] . In many cases, a direct comparison of experimental data and simulation results is possible.…”

Section: Introductionmentioning

confidence: 99%

“…However, at the nanometer scale, such approaches are no more valid and must be replaced by models treating thermal transport at the phonon level. Nowadays, most theoretical investigations of nanoscale thermal transport are based either (i) on the linearized Boltzmann Transport Equation with Fermi's Golden Rule 15,16,20,21 , (phonon quantum confinement neglected) (ii) on Equilibrium Molecular Dynamics simulations 23 (computationally very intensive and statistical average over long time periods required), (iii) on first-principle (ab-initio) methods 19 (limited to very small systems), or (iv) on coherent phonon Non-equilibrium Green's Function (NEGF) approaches 12,17,22 (no dissipative interactions). The versatility and flexibility of NEGF 25,26 make it one of the most widely-spread and appreciated formalisms to solve quantum transport problems.…”

Section: Introductionmentioning

confidence: 99%

Atomistic modeling of anharmonic phonon-phonon scattering in nanowires

Luisier

2012

Phys. Rev. B

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Phonon transport is simulated in ultra-scaled nanowires in the presence of anharmonic phononphonon scattering. A modified valence-force-field model containing four types of bond deformation is employed to describe the phonon bandstructure. The inclusion of five additional bond deformation potentials allows to account for anharmonic effects. Phonon-phonon interactions are introduced through inelastic scattering self-energies solved in the self-consistent Born approximation in the Nonequilibrium Green's Function formalism. After calibrating the model with experimental data, the thermal current, resistance, and conductivity of <100>-, <110>-, and <111>-oriented Si nanowires with different lengths and temperatures are investigated in the presence of anharmonic phononphonon scattering and compared to their ballistic limit. It is found that all the simulated thermal currents exhibit a peak at temperatures around 200 K if phonon scattering is turned-on while they monotonically increase when this effect is neglected. Finally, phonon transport through Si-Ge-Si nanowires is considered.

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Electron and phonon transport in silicon nanowires: Atomistic approach to thermoelectric properties

Cited by 188 publications

References 32 publications

Structural and tunneling properties of Si nanowires

Structural and tunneling properties of Si nanowires

Thermoelectric properties of finite graphene antidot lattices

Atomistic modeling of anharmonic phonon-phonon scattering in nanowires

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