| 1. |
- Liu, Johan, 1960, et al.
(författare)
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1. Thermal Characterization of Power Devices Using Graphene-based Film
- 2014
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Ingår i: Proceedings - Electronic Components and Technology Conference. - 0569-5503. - 9781479924073 ; , s. 459 - 463
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Konferensbidrag (refereegranskat)abstract
- Due to its atomic structure with sp2 hybrid orbitals and unique electronic properties, graphene has an extraordinarily high thermal conductivity which has been reported to be up to 5000 W/mK. As a consequence, the use of graphene-based materials for thermal management has been subject to substantial attention during recent years in both academia and industry. In this paper, the development of a new type of graphene-based thin film for heat dissipation in power devices is presented. The surface of the developed graphene based film is primarily composed of functionalized graphene oxide, that can be bonded chemically to the device surface and thus minimize the interface thermal resistance caused by surface roughness. A very high in-plane thermal conductivity with a maximum value of 1600 W/mK was detected by laser flash machine regarding to the graphene-based films. To investigate the structure of the graphene-based films, scanning electron microscopy (SEM) and raman spectroscopy were carried out. Finally, LED demonstrators were built to illustrate the thermal performance of graphene-based film and the functional layers. IR camera recorded a 5°C lower temperature of a LED demonstrator with SHT G1000 as the binding layer instead of a commercial thermal conductive adhesive.
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| 2. |
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| 3. |
- Zhao, Changhong, 1984, et al.
(författare)
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Graphene oxide based coatings on Nitinol for biomedical implant applications: Effectively promote mammalian cell growth but kill bacteria
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:44, s. 38124-38134
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Tidskriftsartikel (refereegranskat)abstract
- © The Royal Society of Chemistry 2016. An important clinical challenge is the development of implant surfaces which have good integration with the surrounding tissues and simultaneously inhibit bacterial colonization thus preventing infection. Recently, graphene oxide (GO) a derivative of graphene, has gained considerable attention in the biomedical field owing to its biocompatibility, surface functionalizability and promising antimicrobial activity. In this study gelatin-functionalized graphene oxide (GOGel) was synthesized by a simple one step modification where GO and GOGel were used to develop surface coatings on nitinol substrates. Mouse osteoblastic cell (MC3T3-E1) functions including cell attachment, proliferation and differentiation were investigated on GO-based coatings. The results indicated that MC3T3-E1 cell functions were significantly enhanced on both GO coated nitinol (GO@NiTi) and GOGel coated nitinol (GOGel@NiTi) compared with the control nitinol without coating (NiTi). Especially, the GOGel@NiTi surface exhibited the best performance for cell adhesion, proliferation and differentiation. Additionally the antimicrobial property of GO-based coatings against E. coli was studied with the evaluation of colony forming units (CFU) counting, live/dead fluorescent staining and scanning electron microscope (SEM). We found that the growth of E. coli was inhibited on GOGel@NiTi and particularly on GO@NiTi. SEM images revealed that the cell membrane of bacteria lost their integrity and live/dead fluorescent images confirmed the low live/dead ratio of E. coli after incubation on GOGel@NiTi and GO@NiTi. We conclude that GO-based coatings on NiTi combine the antimicrobial activity and improved biocompatibility and therefore present a remarkable potential in biomedical implant applications.
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| 4. |
- Bao, Jie, et al.
(författare)
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Application of two-dimensional layered hexagonal boron nitride in chip cooling
- 2016
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Ingår i: Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering. - 1005-0930. ; 24:1, s. 210-217
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Tidskriftsartikel (refereegranskat)abstract
- © 2016, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.Research into layered hexagonal boron nitride(h-BN)has recently intensified, due to its superior physicochemical properties compared to that of a typical two-dimensional material. H-BN can be utilized in power chips as both an insulating layer as well as a heat spreader for local hotspots with high heat flux. Single layer h-BN film grown by CVD and h-BN microparticles are respectively transferred onto the surfaces of the thermal evaluation chips, where the influence of h-BN on the heat dissipation performance of the chips can be observed at different power values. The resistance-temperature curve method and infrared thermal imager are both used to measure the temperature of hotspots on the thermal evaluation chips, which can be reduced by between 3~5℃ at 1W after the transfer of h-BN. The cooling efficiency is improved and it can be found that single layer h-BN film shows better heat dissipation ability.
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| 5. |
- Bao, Jie, et al.
(författare)
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Synthesis and Applications of Two-Dimensional Hexagonal Boron Nitride in Electronics Manufacturing
- 2016
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Ingår i: Electronic Materials Letters. - : Springer Science and Business Media LLC. - 1738-8090 .- 2093-6788. ; 12:1, s. 1-16
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Forskningsöversikt (refereegranskat)abstract
- In similarity to graphene, two-dimensional (2D) hexagonal boron nitride (hBN) has some remarkable properties, such as mechanical robustness and high thermal conductivity. In addition, hBN has superb chemical stability and it is electrically insulating. 2D hBN has been considered a promising material for many applications in electronics, including 2D hBN based substrates, gate dielectrics for graphene transistors and interconnects, and electronic packaging insulators. This paper reviews the synthesis, transfer and fabrication of 2D hBN films, hBN based composites and hBN-based van der Waals heterostructures. In particular, this review focuses on applications in manufacturing electronic devices where the insulating and thermal properties of hBN can potentially be exploited. 2D hBN and related composite systems are emerging as new and industrially important materials, which could address many challenges in future complex electronics devices and systems.
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| 6. |
- Bao, Jie, 1982, et al.
(författare)
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Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:July 2016, s. 265501-
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Tidskriftsartikel (refereegranskat)abstract
- The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10°C at a 1000 W/cm2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised.
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| 9. |
- Chen, Huang, et al.
(författare)
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A portable micro glucose sensor based on copper-based nanocomposite structure
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 43:20, s. 7806-7813
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Tidskriftsartikel (refereegranskat)abstract
- Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or treat diabetes. Portable glucose sensors with non-enzymatic catalytic materials have received great attention in recent years. Herein, a facile strategy for fabricating a high-performance electrochemical sensor is proposed. A non-enzymatic three-electrode integrated glucose sensor device based on CuO nano-coral arrays/nanoporous Cu (NCA/NPC) is designed and fabricated. The portable NCA/NPC glucose sensor device exhibits high catalytic activity for glucose. The great performance of the NCA/NPC glucose sensor device derives from the excellent conductivity of the NPC substrate and the high electrocatalytic activity of CuO nano-coral arrays. This device exhibits a high sensitivity of 1621 μA mM -1 cm -2 in the linear range of 0.0005-5.0 mM, low detection limit of 200 nM (S/N = 3), fast response time of 3 s, good anti-interference performance, excellent repeatability and considerable stability for glucose detection. This work will certainly provide an efficient structure and proper catalytic material choices for future non-enzymatic glucose sensors.
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| 10. |
- Chen, S., et al.
(författare)
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An overview of carbon nanotubes based interconnects for microelectronic packaging
- 2017
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Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. - 9781538630556 ; , s. 113-119
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Konferensbidrag (refereegranskat)abstract
- Owing to the great demand in more functions and miniaturization in microelectronic packaging, the dimensions of interconnects has decreased extremely, which has resulted in electrical, thermal, and mechanical reliability issues. To address these issues, carbon nanotube (CNT) has been selected as a promising alternative material for the interconnects in packaging due to its large current density, high thermal conductivity, great flexibility, and low coefficient of thermal expansion (CTE). In this paper, the development of CNTs based vertical interconnects was reviewed. However, the resistivity of CNTs based interconnects was much higher than that of copper interconnects. Thus, this review focused on the resistivity of CNTs-based interconnects in different fabrication process and pointed out what improves the resistivity. In the future, CNTs-Cu nanocomposite with unique properties could be the suitable material for bumps to reduce the resistivity of CNTs based bumps further.
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