Accurate Determination of Interlayer Resistivity of 2-D Layered Systems: Graphene Case Study

Abstract

In this article, we provide an accurate method to determine the interlayer resistivity of 2-D layered systems by directly measuring the resistance at a mono- to bi-layer step and feeding the measurement to a distributed resistance model. We take CVD-grown few-layer graphene (up to four layers) with different twist angles ranging from AB-stacked to totally decoupled graphene as an example. Our results show that the interlayer resistivity of AB-stacked CVD grown bilayer graphene (BLG) is in the range of 50–140 $\Omega $ .m, which is two to five orders of magnitude greater than the previously reported values for AB-stacked graphite. On the other hand, twisted BLG shows an interlayer resistivity as low as ${6}~\Omega $ .m and it decreases monotonically with increasing the twist angle, suggesting that interlayer conduction is not limited by phonon scattering, as previously reported. Furthermore, the total resistance of twisted BLG was found to be about one order of magnitude lower than its AB-stacked counterpart, which might lead to lower delay and energy-delay product in twisted graphene interconnects. In addition to that, the universality of our approach allows for accurate determination of interlayer resistivity of other 2-D layered systems such as metal dichalcogenides.