Effects of substrates and annealing temperatures on the friction of single layer graphene

Abstract Graphene is regarded as a promising solid-state lubricant; however, its frictional properties under varying conditions remains limited. In this study, atomic force microscopy (AFM) is used to measure the frictional behavior of graphene supported on four different substrates. It is found that for hard substrates, roughness reduces the interactions between graphene and substrate, which increases the puckering and consequently leads to the increase of friction. For soft substrates, the large deformation of the substrate is an important reason for the increase of friction. Oxygen plasma treatment and annealing treatment in ambient air are performed to regulate the interactions between graphene and SiO 2 substrate. It is found that the friction on graphene surface decreases gradually with the increase of plasma treatment time. However, increasing the annealing temperature leads to the increase of the friction due to the formation of defects on the graphene surface. These experimental results are interpreted by analyzing the adhesion between the AFM probe and graphene and as well as the defect concentration. This work is of great significance for understanding and regulating the frictional properties of graphene under various conditions.