Effect of thiol adsorption on the electrical resistance of copper ultrathin films

• Thin copper films (20 nm) were deposited via thermal evaporation , with variations in substrate temperature (T s = RT, 330 K, and 390 K). • Films deposited at 330 K exhibited the smallest percolation thickness (12 nm) and aging rates due to their compact morphology, showcasing lower surface roughness (δ) and correlation length (ξ). • Immersion of the films in a dodecanethiol solution (1 mM) in ethanol resulted in significant resistance increment, ranging from 0.1 % to 0.4 %. • By depositing a chromium surfactant layer, the impact of the electron-surface scattering mechanism on resistivity was amplified, leading to a resistance increase of up to 1.2% due to thiols adsorption. • The negatively charged S-head of the adsorbed thiols on the copper oxide surface, altering the charge balance below the Cu 2 O/Cu interface, enhancing the electrical resistance. The impact of thiol adsorption on thin copper films, covered with a copper oxide layer, was investigated using electrical resistance measurements at various stages: during film growth, aging, exposure to air, and immersion in thiol solutions. Thin copper films (20 nm) were thermally evaporated, with variations in substrate temperature (RT, 330 and 390 K). Films deposited at 330 K exhibited the smallest percolation thickness and aging rates due to their compact morphology, showcasing lower surface roughness and correlation length. Exposure to air led to the formation of a Cu 2 O layer on the film surface. Subsequent immersion in a dodecanethiol solution in ethanol resulted in a resistance increase, ranging from 0.1 % to 0.4 %. This change was dependent on the substrate temperature, with the largest difference observed at 330 K. This observation suggests that samples grown at this temperature exhibited the highest electron-surface scattering. Moreover, by depositing a chromium surfactant layer, the impact of this scattering mechanism was amplified, leading to a resistance increase of up to 1.2 %. Mayadas-Shatzkes theory provided a good description of these resistance changes. The negatively charged S-head of the adsorbed thiols alters the electric field experienced by conduction electrons in the Cu 2 O/Cu interface, modifying the electron-surface scattering.