Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 88: Metal substrates: Adsorption of organic / bio molecules IX
O 88.9: Vortrag
Donnerstag, 17. März 2011, 19:15–19:30, PHY C213
Impact of spontaneous structural imperfection on the energy level alignment — •Takuya Hosokai1, Hiroyuki Machida2, Alexander Gerlach1, Satoshi Kera2, Nobuo Ueno2, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, Germany — 2Graduate School of Advanced Integration Science, Chiba university, Japan
We report that structural imperfection in an organic layer affects the electronic structure to result in a serious band-bending in the organic layer and change in the energy level alignment (ELA). Ultraviolet photoelectron spectroscopy (UPS) and metastable atom electron spectroscopy (MAES) were adopted to investigate the thickness dependence of the valence electronic structure and molecular orientation of polar phthalocyanine molecules (chlorogallium phthalocyanine) in thin films grown on graphite. We observed a large band-bending-like shift of occupied molecular orbital bands towards the Fermi level and the vacuum level increases continuously for the as-grown film, whereas these phenomena were considerably less pronounced after annealing the film. High-resolution UPS and MAES measurements showed that structural defects, i.e. Cl-up molecules in bilayer domain boundaries, are the origin of the change in the ELA. Our results indicate that controlling the spontaneous structural imperfection is a key for the desired energy level alignment of polar organic thin films on this substrate.