TY - JOUR

T1 - Unoccupied electronic states and the interface formation between oligo(phenylene-vinylene) films and a Ge(111) surface

AU - Komolov, AS

PY - 2004

Y1 - 2004

N2 - 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".

AB - 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".

KW - TARGET CURRENT SPECTROSCOPY

KW - CU-PHTHALOCYANINE FILMS

KW - ENERGY-LEVEL ALIGNMENT

KW - PHOTOELECTRON-SPECTROSCOPY

KW - SEMICONDUCTOR SURFACES

KW - BAND-STRUCTURE

KW - OLIGO(PHENYLENEVINYLENE)S

KW - HYDROCARBONS

KW - POLYMERS

M3 - статья

VL - 49

SP - 630

EP - 634

JO - Technical Physics

JF - Technical Physics

SN - 1063-7842

IS - 5

ER -