Thin films of tri-oligo(phenylene-vinylene) end-terminated by di-butyl-thiole (tOPV) were thermally deposited in UHV on Ge(111) substrates. The surface potential and the structure of unoccupied electron states (DOUS) located 5-20 eV above the Fermi level (E-F) were monitored during the film deposition using an incident beam of low-energy electrons according to the total current electron spectroscopy (TCS) method. The electronic work function of the surface changed during the film deposition until it reached a stable value of 4.3 +/- 0.1 eV at a tOPV film thickness of 8-10 nm. Deposition of the tOPV under 3 nm led to the formation of intermediate DOUS structures that were replaced by another DOUS structure along with an increase in the tOPV deposit thickness up to 8-10 nm. The occurrence of the intermediate DOUS structure is indicative of a substantial reconfiguration of the electronic structure of the tOPV molecules due to the interaction with the Ge(111) surface. Analysis of the TCS data allowed us to assign the unoccupied electronic bands in tOPV located at 5.5-6.5 and 7.5-9.5 eV above the E-F as pi* bands and at 11-14 and 16-19 eV above E-F as sigma* bands. (C) 2004 MAIK "Nauka/Interperiodica".

Original languageEnglish
Pages (from-to)630-634
Number of pages5
JournalTechnical Physics
Volume49
Issue number5
StatePublished - 2004

    Research areas

  • TARGET CURRENT SPECTROSCOPY, CU-PHTHALOCYANINE FILMS, ENERGY-LEVEL ALIGNMENT, PHOTOELECTRON-SPECTROSCOPY, SEMICONDUCTOR SURFACES, BAND-STRUCTURE, OLIGO(PHENYLENEVINYLENE)S, HYDROCARBONS, POLYMERS

ID: 18881277