Characterization of Vanadyl-Phthalocyanine Single Crystal Films Grown on KBr and Muscovite Mica by Molecular Beam Epitaxy

Vanadyl phthalocyanine (VOPc) thin films were prepared with molecular beam epitaxy (MBE) technique an KBr (100) and muscovite substrates. Their morphologies are discussed with their scanning electron microscopy (SEM) images and UV/VIS spectra. The VOPc thin film on a muscovite substrate forms phase I at substrate temperature (Ts): 100°C and forms phase II (triclinic structure) at Ts: 200°C and Ts: 300°C.The VOPc thin film deposited for 60 minutes at Ts: 80°C on a KBr (100) substrate composes of unidirectionally-oriented single crystals. The UV/VIS spectrum shows the absorption peaks at about 680 and 780nm. This indicates that the VOPc thin film has a bulk monoclinic phase. The crystals prepared at Ts: 150°C are lager than those at Ts: 100°C and have an absorption peak at 780nm and a shoulder at 810nm. This means that the VOPc thin film on a KBr (100) surface is a composite film of monoclinic and epitaxial growth crystals. At Ts: 200°C, the average size of crystals is about 1×1×0.1μn. The crystal has an absorption peak at 810nm. The film is dominated by eptaxially-grown crystals. The VOPc film prepared with MBE method is dominated by epitaxially-grown crystals with increasing Ts. This means that molecules on KBr surface can migrate with increasing Ts to form epitaxially-grown crystals.