Rb deposition on alkanethiolate monolayers on Au

The performance of many devices utilizing alkali metal (AM) atoms is dependent upon properties of organic thin films used to line the inner walls of the glass vessel in which the system is contained. In this study, two alkanethiolate self-assembled monolayers on Au, 1-dodecanethiolate and 1-octanethiolate, are employed as model systems to investigate alkali metal atom-thin film interactions. Before and after Rb deposition, the alkanethiolate surface is analyzed with x-ray photoelectron spectroscopy (XPS), including angle-resolved XPS and XPS with an applied dc bias. Following Rb deposition, a shift of the C1s core-level to higher binding energy was observed; additionally, with continued Rb deposition, the atomic percent of Rb on the surface was found to saturate. The importance of these observations with regard to atomic magnetometers and the light induced atomic desorption effect are discussed.