Grain Boundary Effect on Electrical Transport Properties of Graphene

Abstract

The presence of grain boundary affects the mechanical strength, thermal dissipation, and charge transport of polycrystalline graphene flakes. There is still a debate on whether the electronic transmission is severely degraded by the grain boundary, especially between simulations and experiments. To address this issue, we performed electrical transport simulations based on pi-orbital tight-binding Hamiltonian. Our results show that the intrinsic grain boundary is almost transparent for the carrier transport, but extrinsic chemical species (e.g., oxygen, hydroxyl) favor the adsorption on interdomain sites and increase the scattering substantially at the boundary region. The experiment, which shows degraded carrier transport due to grain boundary, can be plausibly explained with our theoretical results. To minimize the extrinsic effects of grain boundaries, we suggest doing electrical measurements under ultrahigh-vacuum condition after thermal annealing or applying pulsed current for desorbing the adsobates.