3-Omega Measurements of Vertically Oriented Carbon Nanotubes on Silicon

Hu, Xuejiao; Padilla, Antonio A.; Xu, Jun; Fisher, Timothy S.; Goodson, Kenneth E.

doi:10.1115/1.2352778

Cited by 221 publications

(174 citation statements)

References 14 publications

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“…155 For thin-films on a substrate, 3 method usually measure thermal conductivity in the direction perpendicular to the film plane. By using heaters with width comparable to the film thickness to explore heat spreading inside the film, however, both in-plane and cross-plane thermal conductivity can be 45 determined.…”

Section: 1 3 Methodsmentioning

confidence: 99%

Nanoscale heat transfer – from computation to experiment

Luo

Chen

2013

Phys. Chem. Chem. Phys.

249

208

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Heat transfer can differ distinctly at the nanoscale from that at the macroscale. Recent advancement in computational and experimental techniques has enabled a large number of interesting observations and 5 understanding of heat transfer processes at the nanoscale. In this review, we will first discuss recent advances in computational and experimental methods used in nanoscale thermal transport studies, followed by reviews of novel thermal transport phenomena at the nanoscale observed in both computational and experimental studies, and discussion on current understanding of these novel phenomena. Our perspectives on challenges and opportunities on computational and experimental 10 methods are also presented. IntroductionHeat transfer at the nanoscale can differ distinctly from that predicted by classical laws.1 Understanding nanoscale heat transfer will help thermal management of electronic, optical, and 15 optoelectronic devices, and design new materials with different thermal transport properties for energy conversion and utilization. Research on nanoscale heat transfer has advanced significantly over the past two decades, and a large number of interesting phenomena have been observed. 20The record-high thermal conductivities were computationally calculated (6600 W/mK at room temperature) 2 and experimentally measured (3500 W/mK at room temperature) 3 in a single-walled carbon nanotube (CNT), a one-dimensional system with thermal conductivity exceeding that of diamond -25 the best known heat conductor in bulk form. The thermal conductivities of CNTs are not only high but could also be diverging due to the one-dimensional nature of thermal transport. [4][5][6] Graphene 7 has also been reported to have exceptionally high thermal conductivity (5800 W/mK). Polymers, such as polyethylene, are usually regarded as thermal insulators in the amorphous phase (~0.3 W/mK). 9 However, simulations suggest that along a polyethylene molecular chain, thermal conductivity is high and could even be divergent.10 Ultradrawn polyethylene nanofibers are found to have thermal 35 conductivities (~100 W/mK) hundreds of times higher than their amorphous counterparts. 11 In fluids suspended with nanoparticles, thermal conductivity enhancement way beyond the amount predicted by traditional effective medium theory has been reported. 12,13 This observation has inspired a large amount of 40 research both theoretically and experimentally to explore the mechanism and applications of the enhanced thermal transport in nanofluids. [14][15][16][17][18][19] Theories have predicted that radiative heat transfer between objects separated at small distances increase significantly with decreasing separations, supported by a few 45 prior experiments performed at micrometer or larger separations. [20][21][22] Recent experiments have pushed the separations between surfaces to tens of nanometers, and radiative heat transfer many orders of magnitude higher than that predicted by Planck's blackbody radiation law has been reported. Besides the high and inc...

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Section: 1 3 Methodsmentioning

confidence: 99%

Nanoscale heat transfer – from computation to experiment

Luo

Chen

2013

Phys. Chem. Chem. Phys.

249

208

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“…Another similar scenario is nanowire or nanotube arrays used as thermal interface materials. [11][12][13][14][15][16][17] Although heat spreading from an isolated nanotube to a substrate is highly ballistic, [18][19][20] it is not clear whether the same effect exists for arrays of nanowires and nanotubes as used for real thermal interface materials.…”

Section: Introductionsmentioning

confidence: 99%

Disparate quasiballistic heat conduction regimes from periodic heat sources on a substrate

Zeng

Chen

2014

Journal of Applied Physics

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ABSTRACT:We report disparate quasiballistic heat conduction trends for periodic nanoscale line heaters deposited on a substrate, depending upon whether measurements are based on the peak temperature of the heaters or the temperature difference between the peak and the valley of two neighboring heaters. The degree of quasiballistic transport is characterized by the effective thermal conductivities of the substrate which are obtained by matching the diffusion solutions to the phonon Boltzmann transport equation (BTE) results. We find that while the ballistic heat conduction effect based on the peak temperature diminishes as the two heaters become closer, it becomes stronger based on the peak-valley temperature difference. Our results also show that the collective behavior of closely spaced heaters can counteract the nonlocal effects caused by an isolated nanoscale hot spot. These results are relevant to thermal conductivity spectroscopy techniques under a) To whom correspondence should be addressed. Electronic mail: gchen2@mit.edu 2 development and also have important implications for understanding nonlocal heat conduction in integrated circuits and carbon nanotube array thermal interface materials.

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“…This trend has been observed in independent thermal measurements with aligned MWCNT 14 and SWCNT films, 15,16 however there could be a wide variation in the measured conductivities depending on the presence of noncarbon content and structural order of the tubes. To interpret this difference, we performed thermal resistance measurements as a function of applied pressure on the sprayed MWCNT and SWCNT samples using the ASTM D5470 17 thermal resistance test method.…”

Section: Resultsmentioning

confidence: 69%

High-performance carbon nanotube coatings for high-power laser radiometry

Ramadurai

Cromer

Lewis

et al. 2008

Journal of Applied Physics

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Radiometry for the next generation of high-efficiency, high-power industrial lasers requires thermal management at optical power levels exceeding 10 kW. Laser damage and thermal transport present fundamental challenges for laser radiometry in support of common manufacturing processes, such as welding, cutting, ablation, or vaporization. To address this growing need for radiometry at extremely high power densities, we demonstrate multiwalled carbon nanotube (MWCNT) coatings with damage thresholds exceeding 15 000 W/cm2 and absorption efficiencies over 90% at 1.06 μm. This result demonstrates specific design advantages not possible with other contemporary high-power laser coatings. Furthermore, the results demonstrate a performance difference between MWCNTs and single-walled carbon nanotube coatings, which is attributed to the lower net thermal resistance of the MWCNT coatings. We explore the behavior of carbon nanotubes at two laser wavelengths (1.06 and 10.6 μm) and also evaluate the optical-absorption efficiency and bulk properties of the coatings.

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3-Omega Measurements of Vertically Oriented Carbon Nanotubes on Silicon

Cited by 221 publications

References 14 publications

Nanoscale heat transfer – from computation to experiment

Nanoscale heat transfer – from computation to experiment

Disparate quasiballistic heat conduction regimes from periodic heat sources on a substrate

High-performance carbon nanotube coatings for high-power laser radiometry

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