title: The growth of α-sexithiophene films on Ag(111) studied by means of PEEM with linearly polarized light.
abstract: In this study, we used photo electron emission microscopy (PEEM) to investigate the growth of α-sexithiophene (α-6 T) on Ag(111) surfaces. The experiments were carried out with linearly polarized ultraviolet-light (Hg lamp with hν=4.9 eV) in order to probe the alignment of the molecules on the surface. In particular, we acquired images before, during, and after growth while changing the polarization in a stepwise manner. For the stationary states of the clean and the α-6 T covered surfaces, we monitored the local electron yield and the intensity of the ultraviolet C-light (100-280 nm) reflected from the whole sample using PEEM and a photodiode, respectively. Due to the high ionization potential (IP>5 eV), there is no direct photoelectron emission from the organic crystallites. However, the photoelectron emission of the metal/organic interface is influenced by anisotropic absorption of the incident light beam, since the adsorbed molecules act as dichroic filters with distinct orientations.
authors.affiliation: Institute of Experimental Physics at the Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria. Electronic address: thorsten.wagner@jku.at.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Wagner
authors.affiliation: Institute of Experimental Physics at the Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria. Electronic address: ebrahim.ghanbari@jku.at.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Ghanbari
authors.affiliation: Institute of Experimental Physics at the Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Huber
authors.affiliation: Institute of Experimental Physics at the Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria. Electronic address: peter.zeppenfeld@jku.at.
authors.forename: Peter
authors.initials: P
authors.lastname: Zeppenfeld
keywords: Ag(111); Linearly polarized light; Optical reflectivity; Photo electron emission microscopy (PEEM); Surface anisotropy; Wetting layer; α-Sexithiophene