Electronic structure of α-sexithiophene ultrathin films grown on

We investigated the electronic states of α-sexithiophene (α-6T) on by means of angle-resolved photoelectron spectroscopy using synchrotron radiation. The characteristic features of π states are observed in the valence region. The increase in the population of the S1 band, assigned to the surface state of , upon deposition of α-6T was measured and the change in the electron density was evaluated. The band diagram was constructed based on the measurement of the HOMO level and work function. The work function was found to change with the α-6T thickness in a characteristic manner. We constructed a model of the electron transfer at each growth stage based on the core levels of the substrate (Si 2p, Ag 3d) and α-6T molecule (C 1s, S 2p), as well as the valence state and work function change.