Maximizing Alloy Graphene Interface Conductance

We present high throughput thermal conductance data at alloy/graphene interfaces as a function of alloy composition and adhesion layer thickness, with a maxima observed at 10 at. % Pd in Ni without an adhesion layer. Graphene contact research has been exclusively limited to pure metals, where the metal/graphene interface inhibits the flow phonons, quantified by the thermal interface conductance. For future electronics to fully capitalize on the revolutionary transport properties of graphene, sufficient heat dissipation at the contact interface is critical to performance. [1]
To make high throughput measurements, metal films with a continuous alloy composition gradient spanning two pure metals were deposited on monolayer graphene on SiO₂/Si substrates. Frequency domain thermoreflectance was used to measure thermal interface conductance as a function of metal composition. Future measurements of electrical contact resistance will be done through transmission line measurement structures, in order to determine the optimal alloy concentration for both electrical and thermal transport across the interface.

[1] P. E. Hopkins, M. Baraket, E. V. Barnat, T. E. Beechem, S. P. Kearney, J. C. Duda, J. T. Robinson, and S. G. Walton, Nano Lett. 12, 590 (2012).