1 The Mads Clausen Institute, Faculty of Engineering, SDU2 SDU NanoSYD, The Mads Clausen Institute, Faculty of Engineering, SDU3 Graz University of Technology, Institute of Solid State Physics4 SDU NanoSYD, The Mads Clausen Institute, Faculty of Engineering, SDU5 The Mads Clausen Institute, Faculty of Engineering, SDU
Organic molecular beam grown -sexithiophene (-6T) forms nanostructured thin films on buckminsterfullerene (C60) thin film layers. At substrate temperatures of 300K during growth a rough continuous film is observed, which develop to larger elongated islands and dendritic- as well as needle like structures at temperatures around 390K. X-ray diffractrometry reveals (100) crystalline orientation in the films grown at higher surface temperatures, which corresponds to upright oriented molecules. Rocking curves reveal the lowest mosaicity for samples grown at the highest substrate temperatures. From fluorescence polarimetry measurements the in-plane orientation of the crystalline sites within the needle like structures is determined. The polarimetry investigations strongly indicate that the needle like structures consist of lying molecules.