Berlin 2005 – scientific programme

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DS: Dünne Schichten

DS 24: Postersitzung II

DS 24.10: Poster

Tuesday, March 8, 2005, 17:00–19:00, Poster TU B

Influence of superlattice structure on the optical properties of organic materials — •Sascha Hermann, Ovidiu Gordan, Marion Friedrich, and Dietrich Zahn — Institut für Physik-Halbleiterphysik TU-Chemnitz, D-09107 Chemnitz, Germany

While the optical properties of inorganic superlattices are well known there is so far only very little work on organic superlattices. This work deals with the preparation and investigation of multilayered organic heterostructures. The organic superlattices of alternating layers consist of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and copper phthalocyanine (CuPc). Samples were prepared by organic molecular beam deposition in high vacuum on H-passivated Si(111) kept at room temperature. Typical thicknesses of individual layers are in the range of 2.5-10nm. The samples were studied by spectroscopic ellipsometry in the range of 0.73 to 5eV and infrared spectroscopy (IR). The IR-results reveal that there is no chemical interaction between the constituents at the interface. The evaluation of the ellipsometry measurements however reveal that the optical response can not be described by superimposing the optical response of single layers. This suggests that there is electronic coupling between the orbitals of the PTCDA and CuPc at the interface.