In situ investigation of structural properties during formation of pentacene thin film on Ag(110) with MBE-LEED

The structural transition of pentacene thin films on single Ag(110) crystals has been directly observed using a home-designed in situ low-energy electron diffraction during the course of absorption and subsequently changes of substrate temperature. The pentacene molecules showed the evolution from disordered structure in the submonolayer region to a well-ordered structure in the monolayer on the substrate at room temperature. The experimental and theoretical results showed that the molecules lay flat on the Ag(110) surface with two domain orientations mirrored with respect to the crystal axis of the silver substrate. Furthermore, the ordered structures can keep stable when the substrate temperature is below the sublimation temperature of pentacene.