| 1. |
- Jing, Lin, et al.
(författare)
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Thermal Conductivity Enhancement of Coaxial Carbon@Boron Nitride Nanotube Arrays
- 2017
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 9:17, s. 14555-14560
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the thermal conductivity enhancement of the vertically aligned carbon nanotube (CNT) arrays (from ?15.5 to 29.5 W/mK, ?90% increase) by encapsulating outer boron nitride nanotube (BNNT, 0.97 nm-thick with ?3-4 walls). The heat transfer enhancement mechanism of the coaxial C@BNNT was further revealed by molecular dynamics simulations. Because of their highly coherent lattice structures, the outer BNNT serves as additional heat conducting path without impairing the thermal conductance of inner CNT. This work provides deep insights into tailoring the heat transfer of arbitrary CNT arrays and will enable their broader applications as thermal interface material.
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| 2. |
- Zhang, Yong, 1982, et al.
(författare)
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Characterization and simulation of liquid phase exfoliated graphene-based films for heat spreading applications
- 2016
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 106, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- This paper concerns the thermal properties of graphene-based films for heat spreading applications. Following liquid phase exfoliation (LPE) films were made by two different methods, vacuum filtration and drop coating. Temperature decreases of up to 6 °C and 4 °C were measured at a heat flux density of 1200 W/cm2 for the vacuum filtrated and drop coated films respectively. For the first time in this paper, three different methods were combined to evaluate and predict the thermal performance of such graphene-based films. Resistance thermometers were used to monitor the hotspot temperature decrease versus the Joule heat flow as a result of using graphene-based heat spreaders. The 3ω method was used to experimentally determine the in-plane and through-plane thermal conductivities of such films. A finite element model of the hotspot test structure was setup using the in-plane and through-plane thermal conductivities (110 and 0.25 W/mK, respectively) obtained from the 3ω measurements. Simulations were performed to predict the hotspot temperature decrease with excellent agreement obtained between all methods. The results indicate that the alignment and purity of the graphene-based films, as well as their thermal boundary resistance with respect to the chip, are key parameters when determining the thermal performance of graphene-based heat spreaders.
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| 3. |
- Zhang, Yong, 1982, et al.
(författare)
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Synthesis and characterization of three-dimensional graphene foams by chemical vapor deposition
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 139-142
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Konferensbidrag (refereegranskat)abstract
- As a three-dimensional porous structure made of two-dimensional graphene building blocks, graphene foam, has gained enormous attention in recent years. Such graphene foam integrates graphene sheets into macroscopic structures meanwhile inheriting most of the fascinating intrinsic properties of graphene. Together with its ultralow density, high porosity and flexibility, graphene foam has been proposed in many applications, such as supercapacitors, microwave shielding, electrochemical sensing and lithium-ion batteries. In this paper, three-dimensional graphene foams were synthesized by low pressure chemical vapor deposition. The obtained graphene foams were characterized by scanning electron microscopy and Raman spectroscopy. The results show that nickel foam surface was fully covered by graphene. The Raman spectra show that most graphene were multilayer, but monolayer and bilayer graphene were also found in some areas. In addition to this, it was also found that the synthesized graphene has very small D peak, indicating high quality of the synthesized graphene.
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