Characterization of organic/metal interfaces using angle-resolved X-ray photoelectron spectroscopy

Interfaces between organic films and gold substrates were investigated by angle-resolved X-ray photoelectron spectroscopy (ARXPS). We examined the emission angle dependence of the peak position of the ARXP spectra in the Au 4f region, and firstly demonstrated that the ARXPS method enable the observation of the electronic structure of the surface layer of the Au film. By comparing two types of organic adsorbed layer on the An substrate between chemisorption (self-assembled monolayer) and physisorption [p-sexiphenyl (6P)], we found that the electronic structure of the first An layer was changed by the chemical interaction between the Au top layer with the organic adsorbates. We discussed ARXPS results of An deposition on the 6P film to confirm An diffusion in the organic film. These results indicate that ARXPS can elucidate the electronic structural changes of the surface layer of a substrate and the penetration of metals in organic/metal systems.