Regensburg 2007 – scientific programme
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DS: Fachverband Dünne Schichten
DS 2: Organic Thin Films II
DS 2.3: Talk
Monday, March 26, 2007, 11:45–12:00, H32
Arrays of crystalline C60 and pentacene nanocolumns — •jian zhang1, ingo salzmann1, fujun zhang1,2, zheng xu2, siegfried rogaschewski1, jürgen p rabe1, and norbert koch1 — 1Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin — 2Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
Organic nanocolumn arrays have been the focus of many research studies owing to the wide range of potential applications for these structures, particularly in the field of optoelectronics. In our work, crystalline nanocolumnar arrays of two widely studied organic semiconductors, i.e., Fullerene (C60) and pentacene were fabricated by glancing angle deposition (GLAD), and characterized by scanning electron microscopy and X-ray diffraction. For both materials, column diameters of typically 100 nm are found on the transparent conductive oxide ITO, essentially independent of column height (up to 360 nm for pentacene). However, on Si-oxide only C60 formed nanocolumns, while pentacene exhibited a morphology resembling that obtained by regular normal incidence deposition. The molecular surface diffusion length on the substrate is thus identified as critical parameter for the formation of columnar nanostructures by GLAD. Our results indicate that glancing angle deposition is a simple technique to fabricate organic crystalline nanocolumn arrays, and that controlling the molecular surface diffusion via chemical and/or morphological patterning may lead to entirely new functional organic nanostructures.