scholarly journals Inelastic phonon transport across atomically sharp metal/semiconductor interfaces

2021 ◽  
Author(s):  
Houfu Song ◽  
Fang Liu ◽  
Song Hu ◽  
Qinshu Li ◽  
Susu Yang ◽  
...  
Keyword(s):  
High Temperatures ◽  
Heat Dissipation ◽  
Thermal Conductance ◽  
Phonon Transport ◽  
Interface Roughness ◽  
Semiconductor Interfaces ◽  
Debye Temperatures ◽  
Sharp Interfaces ◽  
Heat Carriers ◽  
Interface Thermal Conductance

Abstract Understanding thermal transport across metal/semiconductor interfaces is crucial for heat dissipation of electronics The dominant heat carriers in non-metals, phonons, transport elastically across most interfaces, except for a few extreme cases where the two materials that formed the interface are highly dissimilar with a large difference in Debye temperature. In this work we show that even for two materials with similar Debye temperatures (Al/Si, Al/GaN), a substantial portion of phonons will transport inelastically across their interfaces at high temperatures, significantly enhancing interface thermal conductance. Moreover, we find that interface roughness strongly affects phonon transport process. For atomically sharp interfaces, phonons are allowed to transport inelastically and interface thermal conductance linearly increases at high temperatures. With increasing interface roughness, inelastic phonon transport rapidly diminishes. Our results provide new insights on phonon transport across interfaces and open up opportunities to engineering interface thermal conductance specifically for materials of relevance to microelectronics.

Growth of Carbon Nanotubes on Fully Processed Silicon-On-Insulator CMOS Substrates

2008 ◽  
Vol 8 (11) ◽  
pp. 5667-5672 ◽  
Author(s):  
M. Samiul Haque ◽  
S. Zeeshan Ali ◽  
P. K. Guha ◽  
S. P. Oei ◽  
J. Park ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
High Temperatures ◽  
Heat Dissipation ◽  
Thermal Conductance ◽  
Silicon On Insulator ◽  
High Current ◽  
Large Area ◽  
Growth Method ◽  
Soi Cmos

This paper describes the growth of Carbon Nanotubes (CNTs) both aligned and non-aligned on fully processed CMOS substrates containing high temperature tungsten metallization. While the growth method has been demonstrated in fabricating CNT gas sensitive layers for high temperatures SOI CMOS sensors, it can be employed in a variety of applications which require the use of CNTs or other nanomaterials with CMOS electronics. In our experiments we have grown CNTs both on SOI CMOS substrates and SOI CMOS microhotplates (suspended on membranes formed by post-CMOS deep RIE etching). The fully processed SOI substrates contain CMOS devices and circuits and additionally, some wafers contained high current LDMOSFETs and bipolar structures such as Lateral Insulated Gate Bipolar Transistors. All these devices were used as test structures to investigate the effect of additional post-CMOS processing such as CNT growth, membrane formation, high temperature annealing, etc. Electrical characterisation of the devices with CNTs were performed along with SEM and Raman spectroscopy. The CNTs were grown both at low and high temperatures, the former being compatible with Aluminium metallization while the latter being possible through the use of the high temperature CMOS metallization (Tungsten). In both cases we have found that there is no change in the electrical behaviour of the CMOS devices, circuits or the high current devices. A slight degradation of the thermal performance of the CMOS microhotplates was observed due to the extra heat dissipation path created by the CNT layers, but this is expected as CNTs exhibit a high thermal conductance. In addition we also observed that in the case of high temperature CNT growth a slight degradation in the manufacturing yield was observed. This is especially the case where large area membranes with a diameter in excess of 500 microns are used.

scholarly journals Heat transport through propagon-phonon interaction in epitaxial amorphous-crystalline multilayers

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Takafumi Ishibe ◽  
Ryo Okuhata ◽  
Tatsuya Kaneko ◽  
Masato Yoshiya ◽  
Seisuke Nakashima ◽  
...  
Keyword(s):  
Group Velocity ◽  
Density Of States ◽  
Heat Dissipation ◽  
Lattice Mismatch ◽  
Lead Telluride ◽  
Amorphous Layer ◽  
Interface Layer ◽  
Phonon Transport ◽  
Nanoscale Systems ◽  
Phonon Group Velocity

AbstractManaging heat dissipation is a necessity for nanoscale electronic devices with high-density interfaces, but despite considerable effort, it has been difficult to establish the phonon transport physics at the interface due to a “complex” interface layer. In contrast, the amorphous/epitaxial interface is expected to have almost no “complex” interface layer due to the lack of lattice mismatch strain and less associated defects. Here, we experimentally observe the extremely-small interface thermal resistance per unit area at the interface of the amorphous-germanium sulfide/epitaxial-lead telluride superlattice (~0.8 ± 4.0 × 10‒9 m2KW−1). Ab initio lattice dynamics calculations demonstrate that high phonon transmission through this interface can be predicted, like electron transport physics, from large vibron-phonon density-of-states overlapping and phonon group velocity similarity between propagon in amorphous layer and “conventional” phonon in crystal. This indicates that controlling phonon (or vibron) density-of-states and phonon group velocity similarity can be a comprehensive guideline to manage heat conduction in nanoscale systems.

Scanning Thermal Microscopy of Carbon Nanotubes

2000 ◽  
Author(s):  
Li Shi ◽  
Sergei Plyasunov ◽  
Adrian Bachtold ◽  
Paul L. McEuen ◽  
Arunava Majumdar
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Imaging ◽  
Heat Dissipation ◽  
Energy Transport ◽  
Imaging Technique ◽  
Mechanical Deformation ◽  
Phonon Transport ◽  
Scanning Thermal Microscopy ◽  
Thermal Microscopy ◽  
Nanoelectronic Circuits

Abstract This paper reports the use of scanning thermal microscopy (SThM) for studying heat dissipation and phonon transport in nanoelectronic circuits consisting of carbon nanotubes (CNs). Thermally designed and batch fabricated SThM probes were used to resolve the phonon temperature distribution in the CN circuits with a spatial resolution of 50 nm. Heat dissipation at poor metal-CN contacts could be readily found by the thermal imaging technique. Important questions regarding energy transport in nanoelectronic circuits, such as where is heat dissipated, whether the electrons and phonons are in equilibrium, how phonons are transported, and what are the effects of mechanical deformation on the transport and dissipation properties, are addressed in this work.

scholarly journals Temperature and interlayer coupling induced thermal transport across graphene/2D-SiC van der Waals heterostructure

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Md. Sherajul Islam ◽  
Imon Mia ◽  
A. S. M. Jannatul Islam ◽  
Catherine Stampfl ◽  
Jeongwon Park
Keyword(s):  
High Temperatures ◽  
Thermal Transport ◽  
Van Der Waals ◽  
Thermal Conductance ◽  
Interlayer Coupling ◽  
Phonon Modes ◽  
Out Of Plane ◽  
System Temperature ◽  
Non Equilibrium Molecular Dynamics ◽  
Increasing Temperature

AbstractGraphene based two-dimensional (2D) van der Waals (vdW) materials have attracted enormous attention because of their extraordinary physical properties. In this study, we explore the temperature and interlayer coupling induced thermal transport across the graphene/2D-SiC vdW interface using non-equilibrium molecular dynamics and transient pump probe methods. We find that the in-plane thermal conductivity κ deviates slightly from the 1/T law at high temperatures. A tunable κ is found with the variation of the interlayer coupling strength χ. The interlayer thermal resistance R across graphene/2D-SiC interface reaches 2.71 $$\times$$ × 10–7$${\text{Km}}^{2} /{\text{W}}$$ Km 2 / W at room temperature and χ = 1, and it reduces steadily with the elevation of system temperature and χ, demonstrating around 41% and 56% reduction with increasing temperature to 700 K and a χ of 25, respectively. We also elucidate the heat transport mechanism by estimating the in-plane and out-of-plane phonon modes. Higher phonon propagation possibility and Umklapp scattering across the interface at high temperatures and increased χ lead to the significant reduction of R. This work unveils the mechanism of heat transfer and interface thermal conductance engineering across the graphene/2D-SiC vdW heterostructure.

Thermal Conductance of Nanoparticles: A Study of Phonon Transport in Functionalized Nanodiamond Suspensions

2020 ◽  
Author(s):  
Aaron Bain ◽  
Ethan Languri ◽  
Venkat Padmanabhan ◽  
Jim Davidson ◽  
David Kerns
Keyword(s):  
Thermal Conductivity ◽  
Density Functional ◽  
Transport Theory ◽  
Constitutive Relations ◽  
Thermal Conductance ◽  
Phonon Transport ◽  
Suspension Stability ◽  
Kapitza Resistance ◽  
Conductivity Enhancement ◽  
Underlying Mechanisms

Abstract Nanoparticle additives, with their anomalous thermal conductivity, have attracted attention in research and industry as a novel mode of enhancing the heat transfer mediums. Most studies conducted on nanoparticle suspensions in liquids, pastes, or composites at present have relied on constitutive relations using properties of the bulk substance and of the nanoparticle to explain the effective thermal conductivity. In order to utilize nanoparticles in real world engineering applications, chemical functionalization of the surface of the nanoparticle is frequently employed, either to suspend in liquid applications or to stabilize in arrays. In this study, we have sought to explain the underlying mechanisms of thermal conductivity enhancement taking into consideration the nanoscale effects, such as phonon transport in the nanoparticle coupled with vibrational modes of the surface functional molecules, in order to tailor the functional groups not only for suspension stability but also for minimizing Kapitza resistance at the surface of the nanoparticle. Density functional theory simulations in SIESTA and equilibrium transport theory analysis via GOLLUM2 were used in tandem to evaluate the thermal transport at the nanoparticle to surface ligand junction. By treating the nanoparticle surface and the polymer or acid coating as distinct homogeneous substrates, a model for thermal conductivity becomes more tractable.

scholarly journals High thermal conductive copper/diamond composites: state of the art

2020 ◽  
Vol 56 (3) ◽  
pp. 2241-2274
Author(s):  
S. Q. Jia ◽  
F. Yang
Keyword(s):  
Thermal Conductivity ◽  
Electronic Devices ◽  
Thermal Conductance ◽  
High Thermal Conductivity ◽  
Power Electronic ◽  
Practical Application ◽  
Boundary Area ◽  
Interface Characteristics ◽  
Composite Interface ◽  
Interface Thermal Conductance

Abstract Copper/diamond composites have drawn lots of attention in the last few decades, due to its potential high thermal conductivity and promising applications in high-power electronic devices. However, the bottlenecks for their practical application are high manufacturing/machining cost and uncontrollable thermal performance affected by the interface characteristics, and the interface thermal conductance mechanisms are still unclear. In this paper, we reviewed the recent research works carried out on this topic, and this primarily includes (1) evaluating the commonly acknowledged principles for acquiring high thermal conductivity of copper/diamond composites that are produced by different processing methods; (2) addressing the factors that influence the thermal conductivity of copper/diamond composites; and (3) elaborating the interface thermal conductance problem to increase the understanding of thermal transferring mechanisms in the boundary area and provide necessary guidance for future designing the composite interface structure. The links between the composite’s interface thermal conductance and thermal conductivity, which are built quantitatively via the developed models, were also reviewed in the last part.

Strained effects on the thermal conductance of flexural and in-plane modes in graphene nanoribbons

2019 ◽  
Vol 33 (31) ◽  
pp. 1950383
Author(s):  
Bengang Bao ◽  
Gao-Hua Liao ◽  
Jun He ◽  
Chang-Ning Pan
Keyword(s):  
Transport Properties ◽  
Phonon Mode ◽  
Graphene Nanoribbons ◽  
Thermal Conductance ◽  
Low Frequency ◽  
Phonon Transport ◽  
Frequency Region ◽  
Function Approach ◽  
Non Equilibrium Green’S Function ◽  
Plane Mode

Ballistic thermal transport properties in graphene nanoribbon modulated with strain are investigated by non-equilibrium Green’s function approach. The results show that the strain can suppress the phonon transport of flexural phonon mode (FPM) and enhance the phonon transport of in-plane mode (IPM) in low-frequency region, leading to the reduction in the thermal conductance of FPM and the enhancement in the thermal conductance of IPM. The total thermal conductance is decreased by strain as the reduction in the thermal conductance of FPM overcomes the enhancement in the thermal conductance of IPM.

Large effects of pressure induced inelastic channels on interface thermal conductance

2012 ◽  
Vol 101 (22) ◽  
pp. 221903 ◽  
Author(s):  
Yann Chalopin ◽  
Natalio Mingo ◽  
Jiankuai Diao ◽  
Deepak Srivastava ◽  
Sebastian Volz
Keyword(s):  
Thermal Conductance ◽  
Interface Thermal Conductance
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