AVS 50th International Symposium
    Contacts to Organic Materials Topical Conference Monday Sessions
       Session OM-MoA

Paper OM-MoA4
Au/CuPc Interface: A Photoemission Investigation

Monday, November 3, 2003, 3:00 pm, Room 318/319

Session: Contacts to Molecules and Molecular Films (II)
Presenter: L. Lozzi, INFM and University of L'Aquila, Italy
Authors: L. Lozzi, INFM and University of L'Aquila, Italy
S. Santucci, INFM and University of L'Aquila, Italy
S. La Rosa, Sincrotrone Trieste SCpa,Trieste, Italy
Correspondent: Click to Email
Copper phthalocyanine (CuPc) are deeply investigated for many different applications as thin films. One of the most promising application is the fabrication of photovoltaic cells, in which the CuPc film is the active part.@footnote 1@ Au is a widely used metal for metallic contact, in particular for organic photovoltaic cells, because of its high work fuction. In this study we will show our results on the investigation of the interface between CuPc and Au by means of photoemission. We have deposited, by means of thermal evaporation in ultra high vacuum conditions, very thin Au films on a 70 nm thick CuPc film and we have investigated both core levels and valence band features as a function of the Au thickness. We have used different photon energies (from X-ray to UV) to investigate surface and in depth properties. Moreover we have performed high spatial resolution photoemission experiments (Spectromicroscopy beamline at Elettra Synchrotron Radiation Center, spatial resolution about 0.5@micron@) to investigate the homogeneity of the Au film on the organic film. The evolution of the Au 4f spectrum, as a function of the Au film thickness shows indicates the formation of gold cluster.@footnote 2@ Comparing the valence band acquired using low photon energy with those using X-ray photons, it is evident that these clusters are dispersed inside the organic film. No evident variations are observed in the core levels of the CuPc elements. The spatially resolved photoemsiion spectra do not show any difference of the valence band spectra as a function of the position and also the images, acquired looking at different energies of the valence band, showed a very high homogeneity of the deposition, althought the CuPc surface is quite rough. @FootnoteText@ @footnote 1@ P. Peumans and S.R. Forrest, Appl.Phys.Lett. 79, 126 (2001) @footnote 2@ S.B. Di Censo, S.D. Berry, and E.H. Hartford Jr., Phys.Rev.B38, 8465 (1988).