Single-layer MoS2 on mica: studies by means of scanning force microscopy

Abstract Molecular layers of molybdenum disulfide on mica were studied by scanning force microscopy (SFM). The measured unit cell dimensions, 0.32 and 0.52 nm, are consistent with the bulk structures of both MoS2 and mica, respectively. This is the first example of a study with atomic resolution of two chemically different materials obtained in one and the same SFM image. The MoS2 layer height was found to be 1.3 ± 0.3 nm and was interpreted as being due to the presence of single-layers with variable amounts of water adsorbed on either side and on the mica surface. Furthermore, the occurrence of friction effects between the sample and the probing tip is considered to influence the layer height determination.