Dresden 2009 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 25: Organic Thin Films V
DS 25.2: Vortrag
Mittwoch, 25. März 2009, 18:15–18:30, GER 37
Investigation of the structure of TCNQ molecules on Cu(100) by Helium Atom Scattering — •Katrin Fladischer1,2, Antonio Politano1, Daniel Farías3, and Rodolfo Miranda1,3 — 1Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) Cantoblanco, 28049 Madrid, Spain — 2Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria — 3Departamento de Física de la Materia Condensada and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
The relatively young field of organic electronics can be related to the discovery of the conducting charge-transfer salt TTF-TCNQ in 1973. The salt consists of the two organic compounds TTF (Tetrathiafulvalene) and TCNQ (Tetracyanochinodimethan). We have studied the structure formed by TCNQ on Cu(100) by Helium Atom Scattering (HAS), LEED and Temperature Programmed Desorption (TPD). We have found that adsorption at 110 K followed by thermal annealing leads to the appearance of a well-ordered structure, as demonstrated by the presence of pronounced diffraction peaks in the HAS spectra. The corresponding LEED pattern suggests that molecular self-assembly is accompanied by a reconstruction of the Cu(100) substrate. This information was used to determine the lattice parameters of the TCNQ adlayer structure. Three desorption peaks were observed in the TPD spectra, which indicates that TCNQ desorbs in the temperature range between 200-350K. Finally, HAS was used to measure the phonon dispersion curves of TCNQ/Cu(100) at different scattering conditions.