Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 45: Joint Poster Session
HL 45.16: Poster
Tuesday, March 15, 2011, 18:00–21:00, P1
Structural analysis of homoepitaxial grown surface structures on rubrene single crystals — •T. Schmeiler1, R. J. Stöhr2, J. Wrachtrup2, and J. Pflaum1,3 — 1Inst. Exp. Phys. VI,Julius-Maximilians-Universtiy,97074 Würzburg — 23rd Phys. Inst.,Stuttgart University,70550 Stuttgart — 3ZAE Bayern,97074 Würzburg
Self-assembled pyramidal surface structures on 5,6,11,12-tetraphenyl- tetracen (rubrene) single crystals offer an interesting approach to study exciton transport under spatial confinement [1]. These structures grown by physical vapor deposition could be applicable as organic micro-resonators and e.g. be coupled to single photon sources. Therefore an understanding of structural formation is inevitable. We have used smooth rubrene single crystals as substrates and analyzed the nucleation and growth behavior of homoepitaxially grown rubrene thin films deposited on-top by sublimation in high vacuum. We display different growth phases as a function of substrate temperature T and deposition rate R. Choosing R= 0.25 Å/s a pronounced island growth was observed. In order to establish a relation between the pyramidal structures and the islands, their evolution was investigated at constant T and R for various film thicknesses. The surface topography was determined by AFM measurements and subsequently analyzed by Fourier transformation. We show a straight connection between the initial islands and the macroscopic pyramidal structures enabling the controlled growth of rubrene structures for opto-electronic applications. Financial support by the DFG (project PF385/4) is gratefully acknowledged.[1] R. Stoehr et al., Appl. Phys. Lett. 96 (2010) 231902