Oxygen effect on the interfacial electronic structure of C60 film studied by ultraviolet photoelectron spectroscopy

Oxygen effect on the electronic structure of C60/graphite interface was studied by ultraviolet photoelectron spectroscopy. The film deposited in ultrahigh vacuum showed downward band bending, while the film deposited in O2 (1.3 × 10−2 Pa) did not show such band bending. This change was ascribed to possible origins such as deactivation of unintentional dopant, compensation by O2 working as acceptor, and trap formation by O2.