Details

Autor(en) / Beteiligte

• Hlawacek, Gregor
• Puschnig, Peter
• Frank, Paul
• Winkler, Adolf
• Ambrosch-Draxl, Claudia
• Teichert, Christian

Titel

Characterization of Step-Edge Barriers in Organic Thin-Film Growth

Ist Teil von

• Science (American Association for the Advancement of Science), 2008-07, Vol.321 (5885), p.108-111

Ort / Verlag

Washington, DC: American Association for the Advancement of Science

Erscheinungsjahr

2008

Quelle

Science Online科学在线

Beschreibungen/Notizen

• Detailed understanding of growth mechanisms in organic thin-film deposition is crucial for tailoring growth morphologies, which in turn determine the physical properties of the resulting films. For growth of the rodlike molecule para-sexiphenyl, the evolution of terraced mounds is observed by atomic force microscopy. Using methods established in inorganic epitaxy, we demonstrate the existence of an additional barrier (0.67 electron volt) for step-edge crossing--the Ehrlich-Schwoebel barrier. This result was confirmed by transition state theory, which revealed a bending of the molecule at the step edge. A gradual reduction of this barrier in the first layers led to an almost layer-by-layer growth during early deposition stage. The reported phenomena are a direct consequence of the complexity of the molecular building blocks versus atomic systems.