Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.4: Poster

Wednesday, February 27, 2008, 16:30–19:00, Poster D

Electronic Structure and Charge Transport in Durene Crystals — •Christoph Arndt¹, Frank Ortmann², Karsten Hannewald², Friedhelm Bechstedt², and Jens Pflaum¹ — ¹3. Phys. Institut, Univ. Stuttgart — ²European Theoretical Spectroscopy Facility and IFTO, Friedrich-Schiller-Univ. Jena

The intrinsic charge-carrier mobility defines an important material parameter and allows an understanding of the microscopic transport processes in organic semiconductors. Durene has shown one of the best transport performances in single crystals with room-temperature mobilities up to 5 cm²/Vs [1]. The bandlike transport behavior in combination with the small conjugated pi-electron system makes durene also attractive for theoretical descriptions by ab-initio DFT calculations [2].

In this contribution we present experimental data on the mobility tensor of durene crystals accompanied by a theoretical analysis including the influence of fundamental vibrational modes. Bridgman crystals were grown from purified material and electronically characterized by the time-of-flight technique. To access the anisotropy of the mobility, durene slabs along different crystallographic orientations were prepared and the charge-carrier mobility was determined in the temperature range between 5K and 300K. The measurements showed a significant increase of the hole mobilities towards lower temperatures reaching values as high as 100 cm²/Vs.

[1] Z. Burshtein and D.F. Williams, Phys. Rev. B 15, 5769 (1977).

[2] F. Ortmann, K. Hannewald, and F. Bechstedt, Phys. Rev. B 75, 195219 (2007).