Interface electronic structure of zinc-phthalocyanine on the silver thin-film quantum-well

Electronic structures of a novel interface formed by coverage of organic semiconductor zinc-phthalocyanine (ZnPc) onto a nanometer-thick Ag thin-film with quantized electronic states were investigated by means of angle-resolved photoelectron spectroscopy (ARPES). While the highest occupied molecular orbital position of ZnPc accords with those of a ZnPc overlayer on a bulk Ag substrate having been reported previously, an interface state (IS) revealed different energy position with respect to the bulk case. Absence of the angular-dependence of the IS position strongly suggests that this state is localized at each ZnPc molecule.