SINGLE-LAYER MOS2 ON MICA - STUDIES BY MEANS OF SCANNING FORCE MICROSCOPY

Molecular layers of molybdenum disulfide on mica were studied by scann ing force microscopy (SFM). The measured unit cell dimensions, 0.32 an d 0.52 mm, are consistent with the bulk structures of both MoS2 and mi ca, respectively. This is the first example of a study with atomic res olution 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 a nd was interpreted as being due to the presence of single-layers with variable amounts of water adsorbed on either side and on the mica surf ace. Furthermore, the occurrence of friction effects between the sampl e and the probing tip is considered to influence the layer height dete rmination.