TY - JOUR

T1 - Unoccupied Electron States and the Formation of Interface between Films of Dimethyl-Substituted Thiophene–Phenylene Coolygomers and Oxidized Silicon Surface

AU - Komolov, A. S.

AU - Lazneva, E. F.

AU - Gerasimova, N. B.

AU - Panina, Yu A.

AU - Zashikhin, G. D.

AU - Pshenichnyuk, S. A.

AU - Borshchev, O. V.

AU - Ponomarenko, S. A.

AU - Handke, B.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - The unoccupied electron states and the boundary potential barrier during deposition of ultrathin films of dimethyl-substituted thiophene–phenylene coolygomers of the type of CH3–phenylene–thiophene–thiophene–phenylene–CH3 (CH3–PTTP–CH3) on an oxidized silicon surface have been studied. The electronic characteristics have been measured in the energy range from 5 to 20 eV above the Fermi level using total current spectroscopy (TCS). The structure of the CH3–PTTP–CH3 film surfaces has been studied by atomic force microscopy (AFM), and the atomic compositions of the films have been studied by X-ray photoelectron spectroscopy (XPS). The changes in the maximum intensities measured by the TCS method obtained from the deposited CH3–PTTP–CH3 film and from the substrate during increasing in the organic coating thickness to 6 nm is discussed. The formation of the boundary potential barrier in the n-Si/SiO2/CH3–PTTP–CH3 is accompanied by the decrease in the surface work function from 4.2 ± 0.1 to 4.0 ± 0.1 eV as the organic coating thickness increases to 3 nm. The ratio of atomic concentrations C: S in the CH3–PTTP–CH3 films well corresponds to the chemical formula of CH3–PTTP–CH3 molecules. The roughness of the CH3–PTTP–CH3 coating surface was not higher than 10 nm on the ~10 × 10 μm areas as the total CH3–PTTP–CH3-layer thickness was about 100 nm.

AB - The unoccupied electron states and the boundary potential barrier during deposition of ultrathin films of dimethyl-substituted thiophene–phenylene coolygomers of the type of CH3–phenylene–thiophene–thiophene–phenylene–CH3 (CH3–PTTP–CH3) on an oxidized silicon surface have been studied. The electronic characteristics have been measured in the energy range from 5 to 20 eV above the Fermi level using total current spectroscopy (TCS). The structure of the CH3–PTTP–CH3 film surfaces has been studied by atomic force microscopy (AFM), and the atomic compositions of the films have been studied by X-ray photoelectron spectroscopy (XPS). The changes in the maximum intensities measured by the TCS method obtained from the deposited CH3–PTTP–CH3 film and from the substrate during increasing in the organic coating thickness to 6 nm is discussed. The formation of the boundary potential barrier in the n-Si/SiO2/CH3–PTTP–CH3 is accompanied by the decrease in the surface work function from 4.2 ± 0.1 to 4.0 ± 0.1 eV as the organic coating thickness increases to 3 nm. The ratio of atomic concentrations C: S in the CH3–PTTP–CH3 films well corresponds to the chemical formula of CH3–PTTP–CH3 molecules. The roughness of the CH3–PTTP–CH3 coating surface was not higher than 10 nm on the ~10 × 10 μm areas as the total CH3–PTTP–CH3-layer thickness was about 100 nm.

KW - FIELD-EFFECT TRANSISTORS

KW - THIOPHENE/PHENYLENE CO-OLIGOMERS

KW - THIN-FILMS

KW - TETRACARBOXYLIC DIANHYDRIDE

KW - POLYCRYSTALLINE GOLD

KW - SMALL HYSTERESIS

KW - MOLECULAR FILMS

KW - PERYLENE

KW - DERIVATIVES

KW - MOBILITY

UR - http://www.scopus.com/inward/record.url?scp=85047380011&partnerID=8YFLogxK

UR - http://link.springer.com/10.1134/S1063783418050128

UR - http://www.mendeley.com/research/unoccupied-electron-states-formation-interface-between-films-dimethylsubstituted-thiophenephenylene

U2 - 10.1134/S1063783418050128

DO - 10.1134/S1063783418050128

M3 - Article

AN - SCOPUS:85047380011

VL - 60

SP - 1029

EP - 1034

JO - Physics of the Solid State

JF - Physics of the Solid State

SN - 1063-7834

IS - 5

ER -