Monolayer and bilayer pentacene on Cu (111)

Abstract

The morphology and electronic structure of pentacene (Pn) deposited on Cu(111) was studied using scanning tunneling microscopy (STM) and spectroscopy (STS). Deposition of a multilayer followed by annealing to reduce coverage to a monolayer results in the formation of either of two unique phases: a two-dimensional herringbone structure previously unobserved for any linear acene to our knowledge, or a “random-tiling” structure. Coverage greater than a monolayer promotes the formation of a bilayer phase similar to that observed for Pn/Ag(111). STS shows that the electronic structure of the first layer is strongly modified due to its proximity to the substrate, while the second layer exhibits nearly bulklike electronic structure.