Impact of Polymer Residue Level on the In-Plane Thermal Conductivity of Suspended Large-Area Graphene Sheets

2021 ◽  
Author(s):  
Elisha Mercado ◽  
Julian Anaya ◽  
Martin Kuball
Keyword(s):  
Thermal Conductivity ◽  
Residue Level ◽  
Graphene Sheets ◽  
Large Area

Enhanced thermal conductivity for polyimide composites with a three-dimensional silicon carbide nanowire@graphene sheets filler

2015 ◽  
Vol 3 (9) ◽  
pp. 4884-4891 ◽  
Author(s):  
Wen Dai ◽  
Jinhong Yu ◽  
Yi Wang ◽  
Yingze Song ◽  
Fakhr E. Alam ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Three Dimensional ◽  
Graphene Sheets ◽  
Polyimide Composites ◽  
Polyimide Matrix ◽  
Enhanced Thermal Conductivity

3DSG incorporated into a polyimide matrix greatly enhanced its thermal conductivity (up to 2.63 W m−1 K−1), approximately a 10-fold enhancement in comparison with that of neat polyimide.

Integration of Silver Heat Spreaders in LTCC utilizing Thick Silver Tape in the Co-fire Process

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000062-000066 ◽  
Author(s):  
T. Welker ◽  
S. Günschmann ◽  
N. Gutzeit ◽  
J. Müller
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Junction Temperature ◽  
Large Area ◽  
Heat Spreader ◽  
Integration Density ◽  
Heat Spreaders ◽  
Cte Mismatch ◽  
Pattern Resolution

The integration density in semiconductor devices is significantly increased in the last years. This trend is already described by Moore's law what forecasts a doubling of the integration density every two years. This evolution makes greater demands on the substrate technology which is used for the first level interconnect between the semiconductor and the device package. Higher pattern resolution is required to connect more functions on a smaller chip. Also the thermal performance of the substrate is a crucial issue. The increased integration density leads to an increased power density, what means that more heat has to dissipate on a smaller area. Thus, substrates with a high thermal conductivity (e. g. direct bonded copper (DBC)) are utilized which spread the heat over a large area. However, the reduced pattern resolution caused by thick metal layers is disadvantageous for this substrate technology. Alternatively, low temperature co-fired ceramic (LTCC) can be used. This multilayer technology provides a high pattern resolution in combination with a high integration grade. The poor thermal conductivity of LTCC (3 … 5 W*m−1*K−1) requires thermal vias made of silver paste which are placed between the power chip and the heat sink and reduce the thermal resistance of the substrate. The via-pitch and diameter is limited by the LTCC technology, what allows a maximum filling grade of approx. 20 to 25 %. Alternatively, an opening in the ceramic is created, to bond the chip directly to the heat sink. This leads to technological challenges like the CTE mismatch between the chip and the heat sink material. Expensive materials like copper molybdenum composites with matched CTE have to be used. In the presented investigation, a thick silver tape is used to form a thick silver heat spreader through the LTCC substrate. An opening is structured by laser cutting in the LTCC tape and filled with a laser cut silver tape. After lamination, the substrate is fired using a constraint sintering process. The bond strength of the silver to LTCC interface is approx. 5.6 MPa. The thermal resistance of the silver structure is measured by a thermal test chip (Delphi PST1, 2.5 mm × 2.5 mm) glued with a high thermal conducting epoxy to the silver structure. The chip contains a resistor and diodes to generate heat and to determine the junction temperature respectively. The backside of the test structure is temperature stabilized by a temperature controlled heat sink. The resulting thermal resistance is in the range of 1.1 K/W to 1.5 K/W depending on the length of silver structure (5 mm to 7 mm). Advantages of the presented heat spreader are the low thermal resistance and the good embedding capability in the co-fire LTCC process.

Preparation and Characterization of In Situ Nanocomposites of Graphene Nanosheets/Polyurethane

2019 ◽  
Vol 814 ◽  
pp. 90-95 ◽  
Author(s):  
Guang Lei Lv ◽  
Yuan Yuan Li ◽  
Chen Fei ◽  
Zhi Hao Shan ◽  
Jing Gan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Graphene Nanosheets ◽  
Graphene Sheets ◽  
Microstructural Properties ◽  
Wear Performance ◽  
Polyurethane Composites

Graphene nanosheets/polyurethane (GNS/PU) was prepared in situ by polymerization technique for the manufacture of PU safety shoes soles. The graphene nanosheets/polyurethane composites were characterized for their mechanical properties, thermal conductivity and abrasion resistance, and comparison is made with those of the neat polyurethane. The microstructural properties of GNS/PU were characterized by SEM. The results show that with the increase of the amount of graphene within the range of weight-percentages analyzed, the tensile strength of the composites gradually increases. The tensile strength of the GNS/PU composites increased to 64.14 MPa with 2 wt% GNS, compared with 55.1 MPa for neat PU. When the graphene sheets reached 2 wt%, the abrasion volume reached 71 mm3. Compared with the pure PU, the wear performance of GNS/PU composites was significantly improved.

New method for preparing graphene by peeling graphite and facile fabrication of bulk Bi0.45Sb1.55Te3.02/graphene composites with dense texture and high ZT

RSC Advances ◽  
2015 ◽  
Vol 5 (53) ◽  
pp. 42492-42499 ◽  
Author(s):  
Jingying Cui ◽  
Shanming Li ◽  
Qing Hao ◽  
Huaizhou Zhao ◽  
Hongbo Zhao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
New Method ◽  
Graphene Sheets ◽  
Facile Fabrication

The incorporated graphene sheets acted as a growth template and result in dense texture with laminates, an increased Seebeck efficient, a decreased thermal conductivity, and therefore a 25%-enhanced-ZT in pressure direction.

Strain engineering of thermal conductivity in graphene sheets and nanoribbons: a demonstration of magic flexibility

2011 ◽  
Vol 22 (10) ◽  
pp. 105705 ◽  
Author(s):  
Ning Wei ◽  
Lanqing Xu ◽  
Hui-Qiong Wang ◽  
Jin-Cheng Zheng
Keyword(s):  
Thermal Conductivity ◽  
Strain Engineering ◽  
Graphene Sheets

Effect of Fe on the Microstructure and the Thermal Storage Performances of High-Silicon Aluminum Alloy

2014 ◽  
Vol 915-916 ◽  
pp. 775-779
Author(s):  
Xiao Song Li ◽  
An Hui Cai ◽  
Ji Jie Zeng
Keyword(s):  
Thermal Conductivity ◽  
Expansion Coefficient ◽  
Surface Defect ◽  
Primary Silicon ◽  
High Thermal Conductivity ◽  
Large Area ◽  
Performance Impact ◽  
Storage Performance ◽  
Low Thermal Expansion ◽  
Silicon Sheet

The influence of Fe on microstructure and the expansion coefficient and thermal conductivity of Al-30 wt.% Si alloy was studied. Results show that the primary silicon morphology and size changed significantly after joining the Fe, by angular blocky primary silicon sheet or plate into small pieces and then into a polygonal large lump, edge and angle are passivated. As the content of Fe is 0.3 wt.%, material expansion coefficient and high thermal conductivity. Later, with the increase of the content of Fe, alloy point defect and line defect, surface defect and large area defect increase, the thermal conductivity of materials and inflation performance declined. When the content of Fe is 0.1 wt.%, materials with high thermal conductivity and low thermal expansion coefficient, the heat storage performance impact is minimal.

scholarly journals Multiscale modeling of thermal conductivity of polycrystalline graphene sheets

Nanoscale ◽  
2014 ◽  
Vol 6 (6) ◽  
pp. 3344-3352 ◽  
Author(s):  
Bohayra Mortazavi ◽  
Markus Pötschke ◽  
Gianaurelio Cuniberti
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Multiscale Modeling ◽  
Graphene Sheets ◽  
Multiscale Approach

We developed a multiscale approach to explore the effective thermal conductivity of polycrystalline graphene sheets.

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