Heat transport enhancement of heat sinks using Cu-coated graphene composites

Thermally conductive graphene nanosheets (GNs) decorated with Cu nanoparticles or nanoclusters are synthesized through an efficient microwave-assisted (MA) route followed by thermal reduction. The MA approach incorporated with thermal reduction is capable of uniformly disperse Cu deposits onto GNs, forming Cu/GN heterogeneous films. The dependence of thermal conductivity (k) on the amount of Cu deposits displays a general increasing trend as the Cu loading increases from 15.4 to 51.2 wt%. The k value of Cu/GN films can attain as high as 1912 W/m K at 50 °C. With the aid of Cu deposits, a remarkably improved electrical conductivity (σ) of Cu/GN heterogeneous films is observed, and the relation of k versus σ is also investigated. The enhanced k and σ values is attributed to the fact that the Cu deposits serve not only as interconnecting points but also as fillers, forming stereo conductive framework for thermal transport and electronic conduction. To inspect thermal properties, we employ one software (Comsol, pseudo 3D model) to simulate thermal conduction on Cu, GN, and Cu/GN heat sinks. The simulation result reveals that the Cu/GN heat sink displays more efficient thermal transport as compared to the others. As a result, this work proves that the robust design of Cu/GN heterogeneous film offers an integrated skeleton for thermal diffusivity, benefiting practical applications such as Si-based integrated chip.