Thin bismuth film as a template for pentacene growth

Abstract

Thin Bi(001) films grown by ultrahigh vacuum deposition on Si (111) -7×7 surfaces at room temperature, were annealed at ∼400 K in order to improve their morphology by reducing the step density on the surface. Annealed, well-ordered Bi(001) films have been subsequently used as substrates for growth of pentacene (Pn). It has been determined using low-energy electron microscope that Pn nucleates on Bi(001) into a highly ordered, crystalline layer, with Pn molecules "standing up" on the Bi surface, and the (001) plane on the growth front. Moreover, the Pn layer is aligned with the Bi(001) surface having a "point-on-line" commensurate relationship with the substrate. The PnBi (001) film crystallizes in a bulk-like structure directly from the first Pn layer. Formation of the thin film phase reported for the Pn growth on Si O2 and other inert substrates was not observed in our experiments. © 2005 American Institute of Physics.