The Modulation of Interfacial Thermal Resistance in Graphite

2014 ◽  
Author(s):  
Chenhan Liu ◽  
Zhiyong Wei ◽  
Weiyu Chen ◽  
Juekuan Yang ◽  
Yunfei Chen
Keyword(s):  
Thermal Resistance ◽  
Basal Plane ◽  
Heat Dissipation ◽  
Interaction Strength ◽  
Thermal Conductance ◽  
Transmission Function ◽  
Low Frequency ◽  
Blue Shift ◽  
Mean Free Path ◽  
Interfacial Thermal Resistance

It is demonstrated through the nonequilibrium Green’s function method that the interfacial thermal resistance (Ω) of graphite can be modulated by loading pressure in x direction, x and y directions and all three directions respectively in this paper. For graphite without pressure, the interfacial thermal resistance is about 8×10−9 m2K/W. The pressure in the z direction from tensile −1GPa to compressive 10GPa can reduce the Ω by one order of magnitude, which is caused by the increase in the phonon transmission possibility resulting from the increase in the interlayer interaction strength. And the phonon transmission function has the phenomenon of blue shift in the low-frequency range during the process. The pressure in the x-y plane changes from −10GPa to 1.5GPa has slight impact on the phonon transmission and interfacial thermal resistance Ω while there has no pressure or a small pressure in the z direction. So pressure in the basal plane has slight effect on the interfacial thermal conductance and phonon transmission in the graphite. Furthermore, the discrete layer in the graphite separates mutually when the pressure reaches to the critical value 1∼2GPa in the basal plane or to −2∼−1GPa in the z direction. It is worth noted that low-frequency phonons have larger phonon transmission due to longer mean free path and the soft van der Waals interaction between the neighboring layers. Our results suggest that the interfacial thermal resistance of graphite or few-layer graphene can be modulated in a large scope and then can be applied for both heat dissipation and insulation through the pressure engineering.

Enhancement of Interfacial Thermal Transport by Carbon Nanotube-Graphene Junction

2013 ◽  
Author(s):  
Hua Bao ◽  
Shirui Luo ◽  
Ming Hu
Keyword(s):  
Carbon Nanotube ◽  
Thermal Resistance ◽  
Thermal Transport ◽  
Heat Dissipation ◽  
Thermal Conductance ◽  
Thermal Interface Material ◽  
Interfacial Thermal Resistance ◽  
Material Interfaces ◽  
Material Interface ◽  
Dynamics Simulations

Thermal transport across material interfaces is crucial for many engineering applications. For example, in microelectronics, small interfacial thermal resistance is desired to achieve efficient heat dissipation. Carbon nanotube (CNT) has extremely high thermal conductivity and can potentially serve as an efficient thermal interface material. However, heat dissipation through CNTs is limited by the large thermal resistance at the CNT-material interface. Here we have proposed a CNT-graphene junction structure to enhance the interfacial thermal transport. Non-equilibrium molecular dynamics simulations have been carried out to show that the thermal conductance can be significantly enhanced by adding a single graphene layer in between CNT and silicon. The mechanism of enhanced thermal transport is attributed to the efficient thermal transport between CNT and graphene and the good contact between graphene and silicon surface.

Thermal conductivity of V2O5 nanowires and their contact thermal conductance

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 1138-1143 ◽  
Author(s):  
Qilang Wang ◽  
Xing Liang ◽  
Bohai Liu ◽  
Yihui Song ◽  
Guohua Gao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
Thermal Conductance ◽  
Vital Role ◽  
Interfacial Thermal Resistance ◽  
Li Ion Batteries ◽  
Thermal Measurements ◽  
Li Ion

Thermal measurements of V2O5 nanowires suggest the vital role of interfacial thermal resistance in the heat dissipation in Li-ion batteries.

Thermal conductivity and interfacial Thermal Resistance Behavior for the Polyaniline (C3N)– boron carbide (BC3) Heterostructure

2021 ◽  
Author(s):  
Arian Mayelifartash ◽  
Mohammad Ali Abdol ◽  
Sadegh Sadeghzadeh
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Resistance ◽  
Boron Carbide ◽  
Molecular Dynamics Simulations ◽  
Thermal Conductance ◽  
Interfacial Thermal Resistance ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Non Equilibrium

In this paper, by employing non-equilibrium molecular dynamics simulations (NEMD), the thermal conductance of hybrid formed by polyaniline (C3N) and boron carbide (BC3) in both armchair and zigzag configurations has...

Chip Level Refrigeration of Portable Electronic Equipment Using Thermoelectric Devices

2003 ◽  
Author(s):  
Gary L. Solbrekken ◽  
Kazuaki Yazawa ◽  
Avram Bar-Cohen
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Electronic Equipment ◽  
Interfacial Thermal Resistance ◽  
Maximum Heat ◽  
Power Efficient ◽  
System Sensitivity ◽  
Heat Pumping

It is well established that the power dissipation for electronic components is increasing. At the same time, high performance portable equipment with volume, weight, and power limitations are gaining widespread acceptance in the marketplace. The combination of the above conditions requires thermal solutions that are high performance and yet small, light, and power efficient. This paper explores the possibility of using thermoelectric (TE) refrigeration as an integrated solution for portable electronic equipment accounting for heat sink and interface material thermal resistances. The current study shows that TE refrigeration can indeed have a benefit over using just a heat sink. Performance maps illustrating where TE refrigeration offers an advantage over an air-cooled heat sink are created for a parametric range of CPU heat flows, heat sink thermal resistances, and TE material properties. During the course of the study, it was found that setting the TE operating current based on minimizing the CPU temperature (Tj), as opposed to maximizing the amount of heat pumping, significantly reduces Tj. For the baseline case studied, a reduction of 20–30°C was demonstrated over a range of CPU heat dissipation. The parametric studies also illustrate that management of the heat sink thermal resistance appears to be more critical than the CPU/TE interfacial thermal resistance. However, setting the TE current based on a minimum Tj as opposed to maximum heat pumping reduces the system sensitivity to the heat sink thermal resistance.

Molecular Dynamics Simulation of the Thermal Resistance of Carbon Nanotube – Substrate Interfaces

2009 ◽  
Author(s):  
Daniel J. Rogers ◽  
Jianmin Qu ◽  
Matthew Yao
Keyword(s):  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulation ◽  
Thermal Resistance ◽  
Copper Substrate ◽  
Harmonic Approximation ◽  
Thermal Conductance ◽  
Dynamics Simulation ◽  
Interfacial Thermal Resistance ◽  
Non Equilibrium Molecular Dynamics

The interfacial thermal resistance (ITR) between a carbon nanotube (CNT) and adjoining carbon, silicon, or copper substrate is investigated through non-equilibrium molecular dynamics simulation (NEMD). The theoretical phonon transmission also is calculated using a simplified form of the diffuse mismatch model (DMM) with direct simulation of the phonon density of states (DOS) under quasi-harmonic approximation. The results of theory and simulation are reported as a function of temperature in order to estimate the importance of anharmonicity and inelastic scattering. At 300K, the thermal conductance of CNT-substrate interfaces is ∼1500 W/mm2K for diamond carbon, ∼500 W/mm2K for silicon, and ∼250 W/mm2K for copper.

Thermal transport of small systems

2017 ◽  
Author(s):  
Takahiro Yamamoto ◽  
Kazuyuki Watanabe ◽  
Satoshi Watanabe
Keyword(s):  
Thermal Transport ◽  
Thermal Conductance ◽  
Transmission Function ◽  
Mean Free Path ◽  
Phonon Transport ◽  
Fourier Law ◽  
Small Systems ◽  
One Dimensional ◽  
Sample Dimension ◽  
The Mean

This article focuses on the phonon transport or thermal transport of small systems, including quasi-one-dimensional systems such as carbon nanotubes. The Fourier law well describes the thermal transport phenomena in normal bulk materials. However, it is no longer valid when the sample dimension reduces down to below the mean-free path of phonons. In such a small system, the phonons propagate coherently without interference with other phonons. The article first considers the Boltzmann–Peierls formula of diffusive phonon transport before discussing coherent phonon transport, with emphasis on the Landauer formulation of phonon transport, ballistic phonon transport and quantized thermal conductance, numerical calculation of the phonon-transmission function, and length dependence of the thermal conductance.

Simulation of Interfacial Phonon Transport in Si–Ge Heterostructures Using an Atomistic Green’s Function Method

2006 ◽  
Vol 129 (4) ◽  
pp. 483-491 ◽  
Author(s):  
W. Zhang ◽  
T. S. Fisher ◽  
N. Mingo
Keyword(s):  
Thin Film ◽  
Thermal Resistance ◽  
Green’S Function ◽  
Green's Function ◽  
Function Method ◽  
Thermal Conductance ◽  
Transmission Function ◽  
Phonon Transport ◽  
Silicon Thin Film ◽  
Green’S Function Method

An atomistic Green’s function method is developed to simulate phonon transport across a strained germanium (or silicon) thin film between two semi-infinite silicon (or germanium) contacts. A plane-wave formulation is employed to handle the translational symmetry in directions parallel to the interfaces. The phonon transmission function and thermal conductance across the thin film are evaluated for various atomic configurations. The contributions from lattice straining and material heterogeneity are evaluated separately, and their relative magnitudes are characterized. The dependence of thermal conductance on film thickness is also calculated, verifying that the thermal conductance reaches an asymptotic value for very thick films. The thermal boundary resistance of a single Si∕Ge interface is computed and agrees well with analytical model predictions. Multiple-interface effects on thermal resistance are investigated, and the results indicate that the first few interfaces have the most significant effect on the overall thermal resistance.

Maximum Resolution of a Probe-Based, Steady-State Thermal Interface Material Characterization Instrument

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Ronald J. Warzoha ◽  
Andrew N. Smith ◽  
Maurice Harris
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
High Performance ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Interfacial Thermal Resistance ◽  
Uniform Heat Flux ◽  
Thermal Probe ◽  
Thermal Interface

Thermal interface materials (TIMs) constitute a critical component for heat dissipation in electronic packaging systems. However, the extent to which a conventional steady-state thermal characterization apparatus can resolve the interfacial thermal resistance across current high-performance interfaces (RT < 1 mm2⋅K/W) is not clear. In this work, we quantify the minimum value of RT that can be measured with this instrument. We find that in order to increase the resolution of the measurement, the thermal resistance through the instrument's reference bars must be minimized relative to RT. This is practically achieved by reducing reference bar length. However, we purport that the minimization of reference bar length is limited by the effects of thermal probe intrusion along the primary measurement pathway. Using numerical simulations, we find that the characteristics of the probes and surrounding filler material can significantly impact the measurement of temperature along each reference bar. Moreover, we find that probes must be spaced 15 diameters apart to maintain a uniform heat flux at the interface, which limits the number of thermal probes that can be used for a given reference bar length. Within practical constraints, the minimum thermal resistance that can be measured with an ideal instrument is found to be 3 mm2⋅K/W. To verify these results, the thermal resistance across an indium heat spring material with an expected thermal contact resistance of ∼1 mm2⋅K/W is experimentally measured and found to differ by more than 100% when compared to manufacturer-reported values.

scholarly journals Study on Design of Novel Function/Structure Integration Mounting Plate for Space borne SAR Antenna for Wireless Communication

2021 ◽  
Vol 2083 (2) ◽  
pp. 022095
Author(s):  
Shouli Jiang ◽  
Jia Li ◽  
Tongtong Leng ◽  
Rui Xiao ◽  
Zihao Yang ◽  
...  
Keyword(s):  
High Precision ◽  
Large Scale ◽  
Heat Dissipation ◽  
Control Function ◽  
High Reliability ◽  
Signal Transmission ◽  
Transmission Function ◽  
Low Frequency ◽  
Thermal Control ◽  
Antenna Structure

Abstract A novel lightweight and high-precision synthetic aperture radar (SAR) antenna mounting plate scheme based on functional structure integration technology is proposed. The thermal control function, high and low frequency blind insertion signal transmission function of the system are combined with the antenna structure to greatly reduce the size and weight of SAR antenna. The design verification of a high-density integrated SAR antenna mounting plate breaks through the key process technologies such as accurate splicing of multiple interfaces of the mounting plate, highly reliable cementation of non-uniform honeycomb and large-scale warpage control, and solves the key technical difficulties of high precision, high temperature and high reliability. The results show that the antenna mounting plate (size 649mm × 430mm) the overall flatness is better than 0.28mm, the thickness limit dimension deviation is less than 0.1mm, and the temperature consistency is less than 1.8°C. It can meet the requirements of lightweight, structural stiffness and strength, RF blind plug connection and heat dissipation for space borne SAR antenna.

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