Macroscopically ordered thin films of an organic salt grown by low-pressure organic vapor-phase deposition

We demonstrate the process of low-pressure organic vapor-phase deposition ( LP-OVPD) for the growth of crystalline thin films of the organic charge-tra nsfer salt 4'-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) on amor phous TiO2 substrates. LP-OVPD grown films exhibit polycrystallinity with l ong-range structural ordering limited only by substrate size. Film surface coverage and macroscopic ordering are strongly determined by the preparatio n of the TiO2 surface Frier to growth, The morphology and ordering of the f ilms are also found to depend on the deposition temperature and the composi tion of the precursor molecules. These results suggest that LP-OVPD films a re of sufficient quality for use in optical waveguide and related photonic devices. (C) 1999 Elsevier Science B.V. All rights reserved.