Characterization of Powder Beds by Thermal Conductivity: Effect of Gas Pressure on the Thermal Resistance of Particle Contact Points

2004 ◽  
Vol 21 (4) ◽  
pp. 268-275 ◽  
Author(s):  
Michael Shapiro ◽  
Vladislav Dudko ◽  
Victor Royzen ◽  
Yuri Krichevets ◽  
Samuel Lekhtmakher ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Gas Pressure ◽  
Particle Contact ◽  
Contact Points

Two-Step Raman Method for Interface Thermal Resistance and In-Plane Thermal Conductivity Characterization of Graphene Interface Materials

2016 ◽  
Author(s):  
Man Li ◽  
Yanan Yue
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Graphene Film ◽  
Phonon Transport ◽  
Interfacial Thermal Resistance ◽  
Transfer Model ◽  
Interface Thermal Resistance ◽  
Graphene Interface ◽  
Interface Materials

The negative influence of substrate on in-plane phonon transport in graphene has been revealed by intensive research, whereas the interaction between phonons couplings across graphene/substrate interface and within graphene is still needed to figure out. In this work, we put forward a two-step Raman method to accomplish interface thermal resistance characterization of graphene/SiO2 and in-plane thermal conductivity measurement of supported graphene by SiO2. In order to calculate the interfacial thermal resistance, the temperature difference between graphene and its substrate was probed using Raman thermometry after the graphene film was uniformly electrically heated. Combing the ITR and the temperature response of graphene to laser heating, the thermal conductivity was computed using the fin heat transfer model. Our results shows that the thermal resistance of free graphene/SiO2 is enormous and the thermal conductivity of the supported graphene is significantly suppressed. The phonons scattering and leakage at the interface are mainly responsible for the reduction of thermal conductivity of graphene on substrate. The morphology change of graphene caused by heating mainly determines the huge interfacial thermal resistance and partly contributes to the suppression of thermal conductivity of graphene. This thermal characterization approach simultaneously realizes the non-contact and non-destructive measurement of interfacial thermal resistance and thermal conductivity of graphene interface materials.

Interface Thermal Resistance and Length Effect on Thermal Conductivitiy of SWNT Bundles

2012 ◽  
Author(s):  
Kasim Toprak ◽  
Yildiz Bayazitoglu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Water Medium ◽  
Interface Thermal Resistance ◽  
Contact Points ◽  
Length Fraction ◽  
Vertically Aligned ◽  
Packing System

Using different calculations and measurement methods, the results for the thermal conductivity in a single wall carbon nanotube (SWNT) are compared. Then, the interface thermal resistance effects on the effective thermal conductivity of multiple SWNTs in a hexagonal packing system submerged in oil, air, and water are studied. The results show that as the interface thermal resistance increases, the effective thermal conductivity decreases. Moreover, length, length fraction, and volume fraction effects on the thermal conductivity of the system submerged in a water medium are approximated by including the interface thermal resistances of the nanotube-matrix and nanotube-nanotube. The systems’ length ranged between 500–3000 nm. The created models contain either vertically aligned or non-straight nanotubes. Non-straight nanotubes systems make one or two contact points with other nanotubes. These contact points’ location vary based on the length ratio known as the length fraction. It is found that the effective thermal conductivity of the SWNT bundle has the highest value when they are uniformly aligned and dispersed without contact. As the density and length of the SWNTs increase, the effective thermal conductivity of the bundle system also increases.

Characterization of Interconnect Defects Using Scanning Thermal Conductivity Microscopy

2004 ◽  
Author(s):  
H.W. Ho ◽  
J.C.H. Phang ◽  
A. Altes ◽  
L.J. Balk
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Large Scale

Abstract In this paper, scanning thermal conductivity microscopy is used to characterize interconnect defects due to electromigration. Similar features are observed both in the temperature and thermal conductivity micrographs. The key advantage of the thermal conductivity mode is that specimen bias is not required. This is an important advantage for the characterization of defects in large scale integrated circuits. The thermal conductivity micrographs of extrusion, exposed and subsurface voids are presented and compared with the corresponding topography and temperature micrographs.

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