Investigation of Vapor Adsorption on Molybdenum Disulfide Surfaces by Auger Electron Spectroscopy

The adsorption characteristics of the cleavage and edge surfaces of MoS2 were studied by Auger electron spectroscopy, and the following conclusions were obtained. The cleavage surface of MoS2 has difficulty in adsorbing the vapors, and the adsorbed vapor is easily evaporated from the surface in vacuum. On the contrary, the edge surface of MoS2 adsorbs vapors easily, and is difficult to evaporate. These experimental results could explain the difference in the frictional behaviors of cleavage and edge surfaces of MoS2. Sulfur is usually richer than the estimated stoichiometric value on the MoS2 surface, and even on the adsorbed surface. Ion etching can reduce the sulfur contents to the stoichiometric value. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in New Orleans, Louisiana, October 5–7, 1981