Thermal Property Measurements of Nanotubes, Nanowires, and Nanobelts

2002 ◽  
Author(s):  
Deyu Li ◽  
Arun Majumdar ◽  
Wanyoung Jang ◽  
Zhen Yao ◽  
Philip Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Boundary Scattering ◽  
Theoretical Expectation ◽  
Low Dimensions ◽  
Vlsi Interconnects ◽  
Nanoelectronic Devices ◽  
Ideal Candidate ◽  
Structure Boundary

As materials are confined to low dimensions with a size comparable to the scattering mean free paths, the thermal conductivity is often reduced due to increased boundary scattering. The reduced thermal conductivity is desirable in some applications such as thermoelectric cooling, but is often unwanted for others especially for nanoelectronic devices. An exception of this scaling trend is carbon nanotubes (CNTs). Due to the unique crystalline structure, boundary scattering is nearly absent in CNTs, giving rise to super high thermal and electrical conductivity that makes the CNT an ideal candidate for replacing Cu in future VLSI interconnects. The potential electronic applications have inspired several groups to employ a variety of techniques for measuring the Seebeck coefficient [1], specific heat [2–3], and thermal conductivity [4] of CNT bundles and mats. Estimated thermal conductivity from these measurements is significantly reduced by numerous tube-tube junctions in the sample and is much lower than the theoretical expectation [5–7].

Improving Electrical Conductivity and Thermal Properties of Polymers by the Addition of Carbon Nanotubes as Fillers

MRS Bulletin ◽  
2007 ◽  
Vol 32 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Karen I. Winey ◽  
Takashi Kashiwagi ◽  
Minfang Mu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Polymer Composites ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Aspect Ratios ◽  
Polymer Properties ◽  
The Matrix ◽  
Conductivity Of Nanotubes

AbstractThe remarkable electrical and thermal conductivities of isolated carbon nanotubes have spurred worldwide interest in using nanotubes to enhance polymer properties. Electrical conductivity in nanotube/polymer composites is well described by percolation, where the presence of an interconnected nanotube network corresponds to a dramatic increase in electrical conductivity ranging from 10−5 S/cm to 1 S/cm. Given the high aspect ratios and small diameters of carbon nanotubes, percolation thresholds are often reported below 1 wt% although nanotube dispersion and alignment strongly influence this value. Increases in thermal conductivity are modest (∼3 times) because the inter facial thermal re sis tance between nanotubes is considerable and the thermal conductivity of nanotubes is only 104 greater than the polymer, which forces the matrix to contribute more toward the composite thermal conductivity, as compared to the contrast in electrical conductivity, >1014. The nanotube network is also valuable for improving flame-retardant efficiency by producing a protective nanotube residue. In this ar ticle, we highlight published research results that elucidate fundamental structure–property relationships pertaining to electrical, thermal, and/or flammability properties in numerous nanotube-containing polymer composites, so that specific applications can be targeted for future commercial success.

Thermal Transport Properties of Ag-Based Nanocomposites Containing MWCNTs

2012 ◽  
Vol 1404 ◽  
Author(s):  
M. Inoue ◽  
Y. Hayashi ◽  
H. Takizawa
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Electronic Contribution ◽  
Nanocomposite Powder ◽  
Multi Walled Carbon Nanotubes ◽  
Experimental Values ◽  
Walled Carbon Nanotubes ◽  
Percolation Network

ABSTRACTVariation in thermal conductivity of Ag-based composites by introduction of multi-walled carbon nanotubes (MWCNTs) was investigated. The Ag/MWCNT nanocomposite powder was successfully prepared when appropriate surfactants were used via a sonoprocess. The nanocomposite powder was subsequently cured at 280-300 ºC in air. After curing, the thermal conductivity of the nanocomposites was compared with the electronic contribution to thermal conductivity that was estimated from experimental values of the electrical conductivity. The thermal conductivity of Ag/MWCNT nanocomposites was much higher than the electronic contribution. Therefore, the increase in thermal conductivity of the Ag-based nanocomposites is attributed to phonon transfer along the percolation network of MWCNTs.

Characterization of Thermo-Electric Interface Material with Carbon Nanotubes

2007 ◽  
Vol 1056 ◽  
Author(s):  
Piyush R Thakre ◽  
Yordanos Bisrat ◽  
Dimitris C Lagoudas
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Matrix ◽  
Loss Modulus ◽  
Single Wall Carbon Nanotubes ◽  
Electrical Percolation

ABSTRACTAn approach has been presented in the current work to fabricate and characterize nanocomposite systems for optimizing electrical and thermal properties without sacrificing mechanical properties. An epoxy matrix based nanocomposite system has been processed with different volume fractions of carbon nanotubes. The purpose was to tailor macroscale properties to meet competing performance requirements in microelectronics industy. The nanofiller consisted of comparatively low cost XD grade carbon nanotubes (XD-CNTs) that are optimized for electrical properties. This system was compared with another system consisting of single wall carbon nanotubes (SW-CNTs) as nano-reinforcements in epoxy matrix. The electrical percolation threshold (about seven orders of magnitude increase in electrical conductivity) measured by dielectric spectroscopy was found to be at lower loading weight fraction of SWCNTs (0.015 weight %) as compared to XD-CNTs (0.0225 weight %). However, the electrical conductivity after percolation was higher for XD-CNTs reinforced epoxy with respect to SW-CNTs filled nanocomposites. The governing mechanisms for this phenomenon were investigated using transmission optical microscope. The enhancement in thermal conductivity, measured using differential scanning calorimetry, was found to be moderate at lower weight loadings corresponding to electrical percolation. However, a 90% improvement in thermal conductivity was observed for 0.3 weight percent of XD-CNTs. Dynamic mechanical analysis was performed to measure the storage and loss modulus along with the glass transition temperature. No significant change in modulus values and glass transition temperature was measured for nanocomposites varied filler contents with respect to neat matrix.

Optimization Techniques for CNT Based VLSI Interconnects — A Review

2016 ◽  
Vol 26 (03) ◽  
pp. 1730002 ◽  
Author(s):  
A. Karthikeyan ◽  
P. S. Mallick
Keyword(s):  
Carbon Nanotubes ◽  
Integrated Circuits ◽  
Grain Boundary ◽  
Vlsi Circuits ◽  
Optimization Techniques ◽  
Boundary Scattering ◽  
Vlsi Interconnects ◽  
Technology Node ◽  
Wire Sizing ◽  
Interconnect Material

Interconnects plays an important role in integrated circuits. Copper is used as an interconnect material, but beyond 22[Formula: see text]nm technology node it faces many problems due to grain boundary scattering, and therefore carbon nanotubes are the most promising future interconnect materials. Various techniques and approaches such as driver sizing, repeater sizing, repeater insertion, wire sizing, wire spacing, shielding, boos table repeater were used by various researchers. Many of these techniques can be utilized for future CNT based VLSI interconnects as well. This paper presents a detailed discussion on the techniques and approaches of past, present and future relevant for interconnects of VLSI circuits.

Thermal conductivity from hierarchical heat sinks using carbon nanotubes and graphene nanosheets

Nanoscale ◽  
2015 ◽  
Vol 7 (44) ◽  
pp. 18663-18670 ◽  
Author(s):  
Chien-Te Hsieh ◽  
Cheng-En Lee ◽  
Yu-Fu Chen ◽  
Jeng-Kuei Chang ◽  
Hsi-sheng Teng
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Thermal Management ◽  
Graphene Nanosheets ◽  
Consumer Electronics ◽  
Experimental Results ◽  
Heat Sinks ◽  
Empirical Equations ◽  
The Relationship

The relationship between thermal conductivity (k) and electrical conductivity (ε) values was well described by two empirical equations. The experimental results were obtained within the 323–373 K range, suitably complementing the thermal management of chips for consumer electronics.

scholarly journals Comparative Characterization of Multiscale Carbon Fiber Composite with Long and Short MWCNTs at Higher Weight Fractions

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Michael Zimmer ◽  
Qunfeng Cheng ◽  
Shu Li ◽  
James Brooks ◽  
Richard Liang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Fiber Composite ◽  
Carbon Fiber Composite ◽  
Multiwalled Carbon ◽  
The Matrix ◽  
Carbon Fiber Reinforced Composites ◽  
Multi Walled Carbon Nanotubes

There are documented advantages to using carbon nanotubes (CNTs) in composites for various property enhancements. However, to date, only limited studies have been conducted on using of longer CNTs over 1 mm in length. This study used long multiwalled carbon nanotubes (LMWCNTs) and their longer extended networks to test multiple properties in thermal conductivity, electrical conductivity, mechanical strength, and modulus and then compared these properties to those of shorter multi-walled carbon nanotubes (SMWCNTs). For carbon fiber-reinforced composites, the longer graphite paths from LMWCNTs in the matrix were expected to improve all properties. The longer networks were expected to allow for more undisturbed phonon transportation to improve thermal conductivity. This in turn relates to improved electrical conductivity and better mechanical properties. However, results have shown that the LMWCNTs do not improve or decrease thermal conductivity, whereas the shorter MWCNTs provide mixed results. LMWCNTs did show improvements in electrical, mechanical, and physical properties, but compared to shorter MWCNTs, the results in other certain properties varied. This perplexing outcome resides in the functioning of the networks made by both the LMWCNTs and shorter MWCNTs.

scholarly journals Hybridization effect on Electrical Conductivity and Thermal Behavior of Epoxy/Carbon Nanotubes and Biosynthesized Silver Nanoparticles Composites

2021 ◽  
Author(s):  
Aigbodion Victor Sunday ◽  
Solomon Chijioke Madu ◽  
Uche Chinweoke Ogbuefi ◽  
C.U Nwoji
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Silver Nanoparticles ◽  
Epoxy Polymer ◽  
Electronic Devices ◽  
Potential Reduction ◽  
Hybridization Effect ◽  
Enhanced Thermal Conductivity ◽  
Made In

Abstract An attempt was made in this work to decorated carbon nanotubes(CNTs) in a polymer matrix using biosynthesized silver nanoparticles (GAgNPs) using Cashew leaves as a reduction agent. The new hybrid epoxy-CNTs+ GAgNPs composites were produced by modified solution-stir-cast method. The microstructure, thermal properties, strength, and electrical conductivity of the produced composites were determined. The electrical conductivity of the epoxy polymer has been enhanced from 5.6x10-13S/cm to 4.80x10-3S/cm for epoxy-0.5%CNTs and 9.1x10-3S/cm epoxy-0.5%CNTs-0.5%GAgNPs. GAgNPs was effective used to improve the strength of conducting epoxy-CNTs for electronic devices. The addition of CNTs and GAgNPs to epoxy increases the glass transition temperature. It was established that GAgNPs can be promising materials to enhanced thermal conductivity, strength, electrical conductivity of epoxy-CNTs and recover the potential reduction for electronic devices application.

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