Незаполненные электронные состояния ультратонких пленок тиофен-фенилен со-олигомеров на поверхности поликристаллического золота

The results of studying unoccupied electronic states in the energy range from 5 eV to 20 eV above the Fermi level of ultrathin films of dimethyl-substituted thiophene-phenylene co-oligomers CH3-phenylene-thiophene-thiophene-phenylene-CH3 (CH3-PTTP-CH3) are presented. The films were deposited on two types of surface of polycrystalline Au: ex situ Au layer thermally deposited in a separate chamber, and on the in situ Au surface prepared inside the analytical chamber. The structure of the films was studied by X-ray diffraction (XRD). The formation of a superposition of the amorphous and crystalline phases with a period of 3.8 nm is discussed. Investigations of the energy positioning of the maxima of unoccupied electronic states and of the process of the formation of the potential boundary barrier were carried out by the method of total current spectroscopy (TCS). The maxima of the fine structure of the total current spectra (FSTCS) of the CH3-PTTP-CH3 film 5–7 nm thick did not differ when using different types of Au substrates and the surface of the ZnO semiconductor prepared by the atomic layer deposition (ALD) method. When the CH3-PTTP-CH3 layer was deposited both on the ex situ Au surface and on the in situ Au surface, a slight (about 0.1 eV) increase in the electronic work function was observed with an increase in the coating thickness to 5–7 nm. At such CH3-PTTP-CH3 film thicknesses, the electron work function was determined as 4.7 ± 0.1 eV for the ex situ Au substrate and 4.9 ± 0.1 eV for the in situ Au substrate. The possible influence of the processes of physicochemical interaction at the film – substrate interface on the formation of the potential boundary barrier in the structures under study is discussed.