EFFECT OF APPLIED ELECTRIC-FIELD ON THE MOLECULAR-ORIENTATION OF EPITAXIALLY GROWN ORGANIC FILMS

In order to control and obtain desired molecular orientations, we inve stigated the effects of applying an electric field during the epitaxia l growth of organic crystals in this study. We deposited interdigitate d gold electrodes on polished KCl (001) substrates, and then grew copp er phthalocyanine (CuPc) thin films, applying the voltages during evap oration process. Using an energy dispersive grazing incidence x-ray di ffraction system, we evaluated the orientations of alpha-CuPc crystals relative to the KCl substrates. The CuPc crystals with applied electr ic fields were found to orient in different directions from those of t he usual epitaxially grown films without applied electric fields. Thes e facts suggest that the combination of applying an electric field and epitaxial growth provide us a new method to control the molecular ori entation in the organic thin films. (C) 1997 American Institute of Phy sics.