1 research outputs found
Double-Wall Nanotubes and Graphene Nanoplatelets for Hybrid Conductive Adhesives with Enhanced Thermal and Electrical Conductivity
Improving the electrical and thermal
properties of conductive adhesives is essential for the fabrication
of compact microelectronic and optoelectronic power devices. Here
we report on the addition of a commercially available conductive resin
with double-wall carbon nanotubes and graphene nanoplatelets that
yields simultaneously improved thermal and electrical conductivity.
Using isopropanol as a common solvent for the debundling of nanotubes,
exfoliation of graphene, and dispersion of the carbon nanostructures
in the epoxy resin, we obtain a nanostructured conducting adhesive
with thermal conductivity of ∼12 W/mK and resistivity down
to 30 μΩ cm at very small loadings (1% w/w for nanotubes
and 0.01% w/w for graphene). The low filler content allows one to
keep almost unchanged the glass-transition temperature, the viscosity,
and the curing parameters. Die shear measurements show that the nanostructured
resins fulfill the MIL-STD-883 requirements when bonding gold-metalized
SMD components, even after repeated thermal cycling. The same procedure
has been validated on a high-conductivity resin characterized by a
higher viscosity, on which we have doubled the thermal conductivity
and quadrupled the electrical conductivity. Graphene yields better
performances with respect to nanotubes in terms of conductivity and
filler quantity needed to improve the resin. We have finally applied
the nanostructured resins to bond GaN-based high-electron-mobility
transistors in power-amplifier circuits. We observe a decrease of
the GaN peak and average temperatures of, respectively, ∼30
°C and ∼10 °C, with respect to the pristine resin.
The obtained results are important for the fabrication of advanced
packaging materials in power electronic and microwave applications
and fit the technological roadmap for CNTs, graphene, and hybrid systems