Organic molecular nanowires: N,N′-dimethylperylene-3,4,9,10-bis(dicarboximide) on KBr(001)

Abstract

The growth of N,N′-dimethylperylene-3,4,9,10-bis(dicarboximide) (DiMe-PTCDI) on KBr(001) has been studied by frequency modulation atomic force microscopy. At low coverages, DiMe-PTCDI forms molecular wires with a length of up to 600nm; at higher coverages, wire networks were found. The height of the wires is two or more molecular layers; if the sample is cooled to 250K during evaporation, also wires of one layer are found. All wires grow along the [110] and [1¯10] directions of the KBr(001) substrate. There is no wetting layer of molecules. Atomic resolution of the substrate could be achieved between the wires. Due to their size and shape, the molecular nanowires might act as a model system for organic electronics research on insulating substrates.