| 1. |
- Darmawan, C. C., et al.
(författare)
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Graphene-CNT hybrid material as potential thermal solution in electronics applications
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac). - 9781538630556 ; , s. 190-193
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Konferensbidrag (refereegranskat)abstract
- Graphene and CNT have great potential in electronics applications. This work explored the possibility of integrating 1D CNT and 2D graphene into a 3D covalently bonded structure, i.e. a graphene-CNT hybrid material for thermal management application. The graphene-CNT hybrid material was later investigated morphologically and thermally to observe its heat dissipation capability.
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| 2. |
- Han, H. X., et al.
(författare)
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Functionalization mediates heat transport in graphene nanoflakes
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The high thermal conductivity of graphene and few-layer graphene undergoes severe degradations through contact with the substrate. Here we show experimentally that the thermal management of a micro heater is substantially improved by introducing alternative heat-escaping channels into a graphene-based film bonded to functionalized graphene oxide through amino-silane molecules. Using a resistance temperature probe for in situ monitoring we demonstrate that the hotspot temperature was lowered by similar to 28 degrees C for a chip operating at 1,300 Wcm(-2). Thermal resistance probed by pulsed photothermal reflectance measurements demonstrated an improved thermal coupling due to functionalization on the graphene-graphene oxide interface. Three functionalization molecules manifest distinct interfacial thermal transport behaviour, corroborating our atomistic calculations in unveiling the role of molecular chain length and functional groups. Molecular dynamics simulations reveal that the functionalization constrains the cross-plane phonon scattering, which in turn enhances in-plane heat conduction of the bonded graphene film by recovering the long flexural phonon lifetime.
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| 3. |
- Kabiri Samani, Majid, 1976, et al.
(författare)
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Improving Thermal Transport at Carbon Hybrid Interfaces by Covalent Bonds
- 2018
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Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 5:15
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Tidskriftsartikel (refereegranskat)abstract
- Graphene and carbon nanotubes have received much attention for thermal management application due to their unique thermal performance. Theoretical work suggests that a covalent bond can combine 1D carbon nanotubes with 2D graphene together to extend the excellent thermal property to three dimensions for heat dissipation. This paper experimentally demonstrates the high heat dissipation capability of a freestanding 3D multiwall carbon nanotube (MWCNT) and graphene hybrid material. Using high-resolution transmission electron microscopy and pulsed photothermal reflection measurement method, the covalent bonds between MWCNT and planar graphene are microscopically and numerically demonstrated. Thermal resistance at the junction with covalent bonds is 9×10^−10 Kelvin square meter per watt, which is three orders of magnitude lower than van der Waals contact. Joule heating method is used to verify the extra cooling effect of this 3D hybrid material compared to graphite film. A demonstrator using high power chip is developed to demonstrate the applicability of this hybrid material in thermal application. Temperature at hot spots can be decreased by around 10°C with the assistance of this hybrid material. These findings are very significant for understanding the thermal conduction during combining 1D and 2D carbon material together for future thermal management application.
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| 4. |
- Kabiri Samani, Majid, 1976, et al.
(författare)
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Thermal conductivity measurement of densified carbon nanotube bundles by pulsed photothermal reflectance technique
- 2016
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Ingår i: IMAPS Nordic Annual Conference 2016 Proceedings. - 9781510827226
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Konferensbidrag (refereegranskat)abstract
- Carbon nanotubes (CNTs) were proposed as a promising interconnection material in future miniaturized electronics, owing to their exceptional electrical and thermal properties. A series of CNT bundles with 1 mm diameter were grown on silicon substrate by thermal Chemical Vapor Deposition (CVD) at temperature 700 oC. The as grown CNT bundles were densified by a vapor densification method. SEM analysis shows that the vapor densification is densified the CNT forests, which reduces the air volume fraction to increase thermal conductivity of the CNT bundles. The pulsed photothermal reflectance technique is applied to measure thermal conductivity of the CNT bundle before and after densification and the results show the thermal conductivity of densified CNT bundles increases and capability of making CNT filled through silicon via with better thermal and electrical performance.
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| 5. |
- Nylander, Andreas, 1988, et al.
(författare)
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Reliability investigation of a carbon nanotube array thermal interface material
- 2019
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- As feature density increases within microelectronics, so does the dissipated power density, which puts an increased demand on thermal management. Thermal interface materials (TIMs) are used at the interface between contacting surfaces to reduce the thermal resistance, and is a critical component within many electronics systems. Arrays of carbon nanotubes (CNTs) have gained significant interest for application as TIMs, due to the high thermal conductivity, no internal thermal contact resistances and an excellent conformability. While studies show excellent thermal performance, there has to date been no investigation into the reliability of CNT array TIMs. In this study, CNT array TIMs bonded with polymer to close a Si-Cu interface were subjected to thermal cycling. Thermal interface resistance measurements showed a large degradation of the thermal performance of the interface within the first 100 cycles. More detailed thermal investigation of the interface components showed that the connection between CNTs and catalyst substrate degrades during thermal cycling even in the absence of thermal expansion mismatch, and the nature of this degradation was further analyzed using X-ray photoelectron spectroscopy. This study indicates that the reliability will be an important consideration for further development and commercialization of CNT array TIMs.
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| 6. |
- Nylander, Andreas, 1988, et al.
(författare)
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Thermal Reliability Study of Polymer Bonded Carbon Nanotube Array Thermal Interface Materials
- 2018
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Ingår i: THERMINIC 2018 - 24th International Workshop on Thermal Investigations of ICs and Systems, Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Following Moores law, the development of electronics has led to an exponential increase of transistor density over the last couple of decades. Unfortunately, this trend also gives an increased heat power density in active components. Thermal interface materials (TIMs) are used to decrease the thermal resistance in thermal packages by filling out air gaps that naturally form there. TIMs are at the same time identified as a bottleneck due to their relatively low thermal conductivity. Carbon nanotubes (CNTs) are proposed as a future material for TIMs due to their high thermal conductivity and conformable nature. However, no reliability studies for CNT array TIMs can be found in literature that would demonstrate how these types of interfaces would perform. This is to the authors best knowledge the first reported study on thermal reliability for a CNT array TIM, which will be an important step towards a market realisation.
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