Multiscale Electrothermal Modeling of Nanostructured Devices

Romano, Giuseppe; Carlo, Aldo Di

doi:10.1109/tnano.2011.2129574

Cited by 15 publications

(18 citation statements)

References 27 publications

(27 reference statements)

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“…7 is solved iteratively and the first guess for T (r) is given by a Fourier simulation [25]. Further details regarding the implementation of the spatial domain and the solid angle can be found in [26,25]. Since Eq.…”

Section: Mfp Dependent Btementioning

confidence: 99%

Heat Conduction in Nanostructured Materials Predicted by Phonon Bulk Mean Free Path Distribution

Romano

Grossman

2015

Journal of Heat Transfer

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We develop a computational framework, based on the Boltzmann transport equation (BTE), with the ability to compute thermal transport in nanostructured materials of any geometry using, as the only input, the bulk cumulative thermal conductivity. The main advantage of our method is twofold. First, while the scattering times and dispersion curves are unknown for most materials, the phonon mean free path (MFP) distribution can be directly obtained by experiments. As a consequence, a wider range of materials can be simulated than with the frequency-dependent (FD) approach. Second, when the MFP distribution is available from theoretical models, our approach allows one to include easily the material dispersion in the calculations without discretizing the phonon frequencies for all polarizations thereby reducing considerably computational effort. Furthermore, after deriving the ballistic and diffusive limits of our model, we develop a multiscale method that couples phonon transport across different scales, enabling efficient simulations of materials with wide phonon MFP distributions length. After validating our model against the FD approach, we apply the method to porous silicon membranes and find good agreement with experiments on mesoscale pores. By enabling the investigation of thermal transport in unexplored nanostructured materials, our method has the potential to advance high-efficiency thermoelectric devices.Downloaded From: http://heattransfer.asmedigitalcollection.asme.org/ on 05/24/2015 Terms of Use: http://asme.org/terms

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Section: Mfp Dependent Btementioning

confidence: 99%

Heat Conduction in Nanostructured Materials Predicted by Phonon Bulk Mean Free Path Distribution

Romano

Grossman

2015

Journal of Heat Transfer

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“…which takes into account the applied temperature [23,24]. Once the temperature map has been computed by (6), the initial value for the equilibrium energy density is given using (3).…”

Section: Modelmentioning

confidence: 99%

“…Calculations are based on a module developed within the TiberCAD platform [13,14]. For details related to the numerical implementation of (1), refer to [23].…”

Section: Modelmentioning

confidence: 99%

Mesoscale modeling of phononic thermal conductivity of porous Si: interplay between porosity, morphology and surface roughness

2012

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In this work we compute the effective thermal conductivity of porous Si by means of the phonon Boltzmann transport equation. Simulations of heat transport across aligned square pores reveal that the thermal conductivity can be decreased either by increasing the pore size or decreasing the pore spacing. Furthermore, by including the surface specularity parameter we show that the roughness of the pore walls plays an important role when the pore size is comparable with the phonon mean free path, because to the increase in the surface-to-volume ratio. Thanks to these results, in qualitatively agreement with those obtained with Molecular Dynamics simulations, we gained insights into the scaling of thermal properties of porous materials and interplay between disorder at different length scales. The model, being based on a flexible multiscale finite element context, can be easily integrated with electrical transport models, in order to optimize the figure of merit ZT of thermoelectric devices

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“…These scattering self-energies drive both the electron and phonon populations out of equilibrium and allow for the consideration of coupled electrothermal transport phenomena such as self-heating or localized hot spots. The resulting improvement in the simulation accuracy can be compared to that brought by the extension of the drift-diffusion approach with an energy-balance and electrothermal model [21].…”

Section: Introductionmentioning

confidence: 99%

Atomistic modeling of coupled electron-phonon transport in nanowire transistors

Rhyner

Luisier

2014

Phys. Rev. B

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Self-heating effects are investigated in ultrascaled gate-all-around silicon nanowire field-effect transistors (NWFETs) using a full-band and atomistic quantum transport simulator where electron and phonon transport are fully coupled. The nonequilibrium Green's function formalism is used for that purpose, within a nearest-neighbor sp 3 d 5 s * tight-binding basis for electrons and a modified valence-force-field model for phonons. Electron-phonon and phonon-electron interactions are taken into account through specific scattering self-energies treated in the self-consistent Born approximation. The electron and phonon systems are driven out of equilibrium; energy is exchanged between them while the total energy current remains conserved. This gives rise to local variations of the lattice temperature and the formation of hot spots. The resulting self-heating effects strongly increase the electron-phonon scattering strength and lead to a significant reduction of the ON-current in the considered ultrascaled Si NWFET with a diameter of 3 nm and a length of 45 nm. At the same time, the lattice temperature exhibits a maximum close to the drain contact of the transistor.

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Multiscale Electrothermal Modeling of Nanostructured Devices

Cited by 15 publications

References 27 publications

Heat Conduction in Nanostructured Materials Predicted by Phonon Bulk Mean Free Path Distribution

Heat Conduction in Nanostructured Materials Predicted by Phonon Bulk Mean Free Path Distribution

Mesoscale modeling of phononic thermal conductivity of porous Si: interplay between porosity, morphology and surface roughness

Atomistic modeling of coupled electron-phonon transport in nanowire transistors

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