Unoccupied Electron States and the Formation of Interface between Films of Dimethyl-Substituted Thiophene–Phenylene Coolygomers and Oxidized Silicon Surface
- St. Petersburg State University (Russian Federation)
- Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, Institute of Molecules and Crystals (Russian Federation)
- Russian Academy of Sciences, Enikopolov Institute of Synthetic Polymeric Materials (Russian Federation)
- AGH University of Science and Technology, Faculty of Material Science and Ceramics (Poland)
The unoccupied electron states and the boundary potential barrier during deposition of ultrathin films of dimethyl-substituted thiophene–phenylene coolygomers of the type of CH{sub 3}–phenylene–thiophene–thiophene–phenylene–CH{sub 3} (CH{sub 3}–PTTP–CH{sub 3}) 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 CH{sub 3}–PTTP–CH{sub 3} 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 CH{sub 3}–PTTP–CH{sub 3} 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/SiO{sub 2}/CH{sub 3}–PTTP–CH{sub 3} 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 CH{sub 3}–PTTP–CH{sub 3} films well corresponds to the chemical formula of CH{sub 3}–PTTP–CH{sub 3} molecules. The roughness of the CH{sub 3}–PTTP–CH{sub 3} coating surface was not higher than 10 nm on the ~10 × 10 μm areas as the total CH{sub 3}–PTTP–CH{sub 3}-layer thickness was about 100 nm.
- OSTI ID:
- 22771100
- Journal Information:
- Physics of the Solid State, Vol. 60, Issue 5; Other Information: Copyright (c) 2018 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7834
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electronic states of thiophene/phenylene co-oligomers: Extreme-ultra violet excited photoelectron spectroscopy observations and density functional theory calculations
Elastic, Adhesive, and Charge Transport Properties of a Metal-molecule-metal Junction: the Role of Molecular Orientation, Order, and Coverage
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC FORCE MICROSCOPY
COATINGS
CONCENTRATION RATIO
FERMI LEVEL
INTERFACES
LAYERS
MOLECULES
POLYCYCLIC SULFUR HETEROCYCLES
ROUGHNESS
SILICON
SILICON OXIDES
SUBSTRATES
SURFACE COATING
SURFACES
THICKNESS
THIN FILMS
THIOPHENE
WORK FUNCTIONS
X-RAY PHOTOELECTRON SPECTROSCOPY