| AVS 60th International Symposium and Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS1-ThA |
| Session: | Organic Layers on Surfaces |
| Presenter: | A. Ciszewski, University of Wroclaw, Poland |
| Authors: | K. Lament, University of Wroclaw, Poland P. Mazur, University of Wroclaw, Poland S. Zuber, University of Wroclaw, Poland W. Kaminski, University of Wroclaw, Poland A. Ciszewski, University of Wroclaw, Poland |
| Correspondent: | Click to Email |
Organic nanostructures on semiconductor surfaces offer a variety of applications in modern electronic such as light emitting diodes, transistors, solar cells, etc. In most cases well-ordered interfaces are required. Therefore interest in interfaces between organic molecules and inorganic semiconductors surface and the phenomenon of self-organization is still increasing. The growth of thin molecular films with a commensurate structural relationship to the substrate needs substrates that exhibit template structure into which the molecules can be locked. We apply STM, STS, XPS, UPS, and LEED techniques to study adsorption of PTCDI-C8 (N, N'-Dioctyl-3,4,9,10-perylenedicarboximide) on Si(110). The adsorbate of an average thickness from a fraction of monomolecular layer (ML) up to 1.3 ML was vapor deposited on (16x2) reconstructed surface of n-type, Sb-doped substrate. The reconstruction, typical for clean Si(110) surface, shows a stripe-like structure with alternately spaced lower and higher terraces lying along the [-112] and [1-12] directions. The distance between adjacent raised stripes is about 5 nm and the width of the stripes is about 0.2 nm.
We have found out that the PTCDI-C8 molecules are bound to the surface through oxygen atoms. We have measured the changes of electron affinity of the surface as a function of the average adsorption layer thickness. We were able to observe single molecules of the adsorbate for the layers of the thickness up to 0.6 ML. For these coverage values template effect of the substrate on the PTCDI-C8 ad-layer structure is clearly visible. The molecules form chains along the [-112] and [1-12] directions of the substrate. Conclusions are drawn concerning the chain structure and, with the help of model calculations, the topography of adsorption site for a single molecule in the chain.