Graphene Interlayer for Much Enhanced Interface Thermal Conductance in Metal Matrix Composites: An Approach Beyond Surface Metallization and Matrix Alloying

Abstract

Effective heat dissipation in highly integrated electronic (nano-)devices is being a technical bottleneck in the microelectronic industry, where diamond/copper matrix (Dia/Cu) composite is considered as a promising heat sink material for thermal management applications. However, poor wettability and acoustic mismatch between diamond and Cu lead to low interfacial thermal conductance (ITC), producing much lower thermal conductivity (TC) of such a composite than that of pure Cu. Surface metallization and matrix alloying have widely been utilized for interface engineering by introducing carbide interlayer, while an uniform and nano-sized (< 100 nm) interlayer cannot be obtained and alloying decreases overall TC of matrix. Here, a novel and highly thermal conductive Dia/Cu composite component, using in-situ grown graphene as the highly effective interlayer, was prepared by vacuum hot pressing. The graphene interlayer improves interfacial wetting and mitigates acoustic mismatch between diamond and Cu, thereby improving ITC of composite. As results, the TC of diamond/graphene/copper (Dia/Gr/Cu) composite is 61% higher than that of the Dia/Cu counterpart. Differential effective medium (DEM) calculation further indicates that the Dia/Gr/Cu interface exhibits an ITC ~3.7 times higher than the Dia/Cu counterpart. This study provides a new approach for interface modification by 2D materials for high TC Dia/Cu composite beyond surface metallization and matrix alloying.

Keywords: thermal conductivity, interface modification, diamond, graphene, copper