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DS: Fachverband Dünne Schichten

DS 19: Organic Interfaces (SYSA 6)

DS 19.3: Vortrag

Mittwoch, 27. Februar 2008, 15:15–15:30, H 2013

Structural and optical properties of self-organized surface structures on rubrene single crystals — •Rainer Stöhr¹, Gareth Beirne², Peter Michler², Jörg Wrachtrup¹, and Jens Pflaum¹ — ¹3. Physikalisches Institut, Univ. Stuttgart,Germany — ²IHFG, Univ. Stuttgart, Germany

On the surface of rubrene single crystals high hole mobilities up to 15 cm²/Vs have been observed making this material interesting for organic device applications. However, the optical properties of rubrene single crystals are yet barely analysed.

We present first structural and optical studies on sublimation grown rubrene single crystals with self-organized pyramidal microstructures on the (001) surfaces. From OMBD growth at various conditions we conclude on the stabilization mechanisms of these crystallographically aligned structures.

Measuring the time- and locally-resolved micro-photoluminescence at various positions on the structured rubrene (001) surface, four peaks could be identified in the wavelength range between 500nm and 900nm. The generated microstructures on the crystal surface enhanced the peak intensities by up to an order of magnitude. A clear dependence between structure size and enhancement could be shown. The results are carefully discussed by assigning these peaks to various exciton species with respect to studies currently reported in literature [1].

The DFG (projects WR28/5 and FOR 730) is acknowledged for financial support.

[1] H. Najafov et al., PRL 96, 056604 (2006)