Probing interactions at two-dimensional heterointerfaces by boron nitride-wrapped tip

Abstract

Non-covalent interactions are important for two-dimensional heterointerfaces but challenged to be accurately determined, especially when the dielectric hexagonal boron nitride (BN) is involved. Here, we present a comprehensive quantitative investigation on the interactions at the interfaces of BN-BN, BN-molybdenum disulfide, and BN-graphite using a BN-wrapped atomic force microscope tip and first-principle theory. The critical adhesion forces at BN-molybdenum disulfide and BN-graphite interfaces are measured to be 1.107 ± 0.062 and 0.999 ± 0.053 times that at BN-BN interface, respectively, while increase to 1.195 ± 0.076 and 1.085 ± 0.075 a.u. after exposure of the tip to radiation in scanning electron microscopy, with data repeatability higher than 86%. The result with non-radiated tip agrees with the van der Waals interactions predicted by the state-of-the-art density functional theory-based vdW2D method, whereas the effect of radiation comes from the introduced charges in the tip, indicating the crucial roles of both dispersion and electrostatic interactions in construction, manipulation and device application of two-dimensional heterostructures.