Mo-interlayer-mediated thermal conductance at Cu/diamond interface measured by time-domain thermoreflectance

The interfacial thermal conductance (G) in Cu/diamond composites is generally determined by a deduction from thermal conductivity measurement of the composites. In this article, we prepare a Cu/Mo/diamond sandwich structure by magnetron sputtering to directly measure G between Cu and diamond using time-domain thermoreflectance and to probe the effect of the interlayer on G. The interlayer is tuned to a 105 nm-thick Mo layer on a 5 nm-thick Mo2C layer, to a full Mo2C layer, and to a Mo2C layer on a mixed Mo2C and fullerene layer with annealing temperature. The partial conversion of Mo interlayer benefits the thermal transport between Cu and diamond and a maximum G value of 132 MW m−2 K−1 is obtained for the case of 105 nm-thick Mo layer on 5 nm-thick Mo2C layer. This study highlights the importance of appropriate interlayer insertion to mediate thermal transport at Cu/diamond interface for thermal management applications.