Characterizing Adsorbate-induced Resistivity Changes of Au(111)

A four-probe lock-in technique was used to measure resistivity changes caused by adsorption on 150 nm Au(111) thin films in UHV at a base pressure of 2×10⁻¹⁰ Torr. Samples were cleaned by various combinations of Ar ion sputtering and annealing, and then dosed with either Diethyl Disulfide or Butane Thiol. Auger Electron Spectroscopy was used to characterize the surface condition, and various cleaning protocols were tested to find the greatest resistivity changes. No correlation between Auger results and the size of resistivity change was established. The largest resistivity changes were observed for Diethyl Disulfide adsorption on sputtered films.