The Relationship between Contact Resistance and Contact Force on Au coated Carbon Nanotube surfaces

Carbon-nanotube (CNT) coated surfaces are investigated to determine the electrical contact performance under low force conditions. The surfaces under investigation are multi-walled CNTs formed on a silicon substrate and coated with an Au film. These planar surfaces are mated with a hemispherical Au plated probe mounted in a nano-indentation apparatus. The maximum contact force used is 1 mN. The contact resistance of these surfaces is investigated as a function of the applied force and is also studied under repeated loading cycles. The surfaces are compared with a reference Au-Au contact under the same experimental conditions and the results compared to established contact theory. The results show that the multi-walled CNT surface provides a stable contact resistance, but that the performance could be improved further with the application of single-walled CNT coatings. This initial study shows the potential for the application of CNT surfaces as an interface in low force electrical contact applications.