Balance thermal conductivity and thermal expansion in RGO/Cu composites through alignment engineering

Abstract

Electronic components often exhibit a low service lifetime due to low thermal conductivity (TC) of heat sink plates and large coefficient of thermal expansion (CTE) mismatch between Si heat source and the plate. Herein, high TC and low CTE are achieved simultaneously in Cu composites with aligned reduced graphene oxide (RGO) inside prepared by molecular-level mixing (MLM) combined with spark plasma sintering (SPS). The RGO/Cu pellets exhibit obvious anisotropic alignment morphology between in-plane direction (perpendicular to sintering pressure) and through-plane direction (parallel to sintering pressure). The in-plane TC of RGO/Cu pellets reached up to 332 W m−1K−1, which was close to that of pure Cu. In addition, the through-plane CTE (9.8 ppm K−1) is remarkably smaller than the CTE of pure Cu. On the premise of balancing TC and CTE, this work shows high potential in scalable industrial fabrication for its simple processing, short fabrication duration and low cost.