Thermal properties of amorphous/crystalline silicon superlattices

France‐Lanord, Arthur; Mérabia, Samy; Albaret, Tristan; Lacroix, David; Termentzidis, Konstantinos

doi:10.1088/0953-8984/26/35/355801

Cited by 62 publications

(63 citation statements)

References 43 publications

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“…Typically, structural disorders have been observed only by atomic visualization. 13,14,39,48,49 Therefore, using correct bins is necessary to provide insight into the interface characteristics.…”

Section: The Proper Bin Size For Correct Measurements At Grain Bmentioning

confidence: 99%

Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

Barışık

Kim

2016

The Journal of Chemical Physics

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This study focuses on the proper characterization of temperature profiles across grain boundaries (GBs) in order to calculate the correct interfacial thermal resistance (ITR) and reveal the influence of GB geometries onto thermal transport. The solid-solid interfaces resulting from the orientation difference between the (001), (011), and (111) copper surfaces were investigated. Temperature discontinuities were observed at the boundary of grains due to the phonon mismatch, phonon backscattering, and atomic forces between dissimilar structures at the GBs. We observed that the temperature decreases gradually in the GB area rather than a sharp drop at the interface. As a result, three distinct temperature gradients developed at the GB which were different than the one observed in the bulk solid. This behavior extends a couple molecular diameters into both sides of the interface where we defined a thickness at GB based on the measured temperature profiles for characterization. Results showed dependence on the selection of the bin size used to average the temperature data from the molecular dynamics system. The bin size on the order of the crystal layer spacing was found to present an accurate temperature profile through the GB. We further calculated the GB thickness of various cases by using potential energy (PE) distributions which showed agreement with direct measurements from the temperature profile and validated the proper binning. The variation of grain crystal orientation developed different molecular densities which were characterized by the average atomic surface density (ASD) definition. Our results revealed that the ASD is the primary factor affecting the structural disorders and heat transfer at the solid-solid interfaces. Using a system in which the planes are highly close-packed can enhance the probability of interactions and the degree of overlap between vibrational density of states (VDOS) of atoms forming at interfaces, leading to a reduced ITR. Thus, an accurate understanding of thermal characteristics at the GB can be formulated by selecting a proper bin size. Published by AIP Publishing. [http://dx

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Section: The Proper Bin Size For Correct Measurements At Grain Bmentioning

confidence: 99%

Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

Barışık

Kim

2016

The Journal of Chemical Physics

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“…In Ref. [216] similar results are obtained for a-Si/mass-heavy c-Si SLs where they show a very slight increase in thermal conductivity with temperature.…”

Section: Sensitivity To Ratiosupporting

confidence: 71%

The Role of Electronic and Vibrational Scattering on Thermal Transport Across Multiple Interfaces in Nanostructures

Giri¹

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Rapid miniaturization and faster working speeds in electronic devices has led to challenges in their thermal mitigation. However, thermal conductivity of the constituent materials in the nano-devices, even though a very critical parameter in their design, is mostly overlooked and the thermal performance of the device is mainly controlled through packaging techniques. However, it would be advantageous for a diverse spectrum of technologies, which ultimately fail due to either high density of interfaces or due to high operating frequencies, to control and tune thermal properties at the submicron length scale and femtoto-picosecond time scales. Therefore, a comprehensive understanding of how heat flows across nanosystems that are mostly limited by interfacial thermal transport would prove to be quintessential for the design of various electronic devices. For example, the contribution of electronic thermal resistance across metal/semiconductor interfaces has been a subject of debate for the past several decades; understanding the intrinsic electron-electron, electron-phonon and electron-boundary scattering mechanisms in these devices could potentially lead to transistors with higher operating frequencies. Moreover, with the advent of new fabrication technologies, the role of phononic-driven thermal resistances across hybrid interfaces of inorganic/organic materials and amorphous semiconductor superlattices (SLs) with high density of interfaces has largely been unexplored.It is the goal of this work to comprehensively explore interfacial thermal transport in these material systems by understanding the fundamental scattering mechanisms of the energy carriers, which dominate thermal transport at various length and time scales. In this regard, a combination of time-domain thermoreflectance (TDTR) experiments and non-equilibrium molecular dynamics (NEMD) simulations will be implemented to achieve these goals.The nonequilibrium between electrons and phonons at metal/semiconductor interfaces in high frequency microelectronic devices serves as a bottleneck to heat transfer in these ii devices. To understand this phenomena, TDTR is used to probe the highly non-equilibrium condition that is induced due to pulse absorption by thin Au films deposited on various dielectric substrates. For electron temperature excursions of ≤ 3,500 K in Au, it is shown that while the increase in the excited carrier density increases the e-p coupling in the metal, the bond strength between the metal and the substrate dictates the energy transfer rate across the interface during this highly non-equilibrium time regime. Furthermore, at time scales when the electrons have fully thermalized with the lattice, electron-phonon coupling does not influence the phonon-driven thermal boundary conductance.Another phenomena that lead to device failure are the phonon-driven thermal boundary resistance in multilayered semiconductors used in technologies such as thermoelectric power generation or phase change memory devices. TDTR is used to simultaneously...

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“…Thus, we compute the thermal conductivity of an infinite size system with spherical nano-pores periodically spread across the material. A shell of amorphous Silicon can be added around the pore with a "cut and paste technique" [6,7,8] . The thickness of the shell can also vary.…”

Section: Modeling the Structuresmentioning

confidence: 99%

“…It has been shown that phonons feel the existence of the crystalline/amorphous interface in a distance of almost 1 nm from the interface [6].…”

Section: Effect Of the Amorphous Shellmentioning

confidence: 99%

Effect of the amorphization around spherical nano-pores on the thermal conductivity of nano-porous Silicon

Verdier

Lacroix

Termentzidis

2017

J. Phys.: Conf. Ser.

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Abstract. The thermal conductivity of nano-porous Silicon with amorphous shells around the pores is computed by Molecular Dynamics simulations. For the latter property, a systematic investigation of the porosity and the thickness of the amorphous shells has been performed. Sub-amorphous thermal conductivity is reached for systems with large porosity and amorphous shell, while a non-negligible fraction of crystalline Silicon phase is still present. The thermal conductivity of all studied systems can be controlled by a key parameter which is the ratio of crystalline/amorphous or crystalline/void interface to the volume of material.

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Thermal properties of amorphous/crystalline silicon superlattices

Cited by 62 publications

References 43 publications

Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

Atomic density effects on temperature characteristics and thermal transport at grain boundaries through a proper bin size selection

The Role of Electronic and Vibrational Scattering on Thermal Transport Across Multiple Interfaces in Nanostructures

Effect of the amorphization around spherical nano-pores on the thermal conductivity of nano-porous Silicon

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