Epitaxial growth behavior of copper phthalocyanine films under applied voltages

In order to develop the noble molecular arrangement techniques, we investigated the effects of the electric field on the epitaxial growth process of organic thin films. We deposited interdigitated gold electrodes on KCl substrates, and then grew copper phthalocyanine (CuPc) thin films, with applying the electric voltages during the evaporation process. Using an energy dispersive grazing incidence x-ray diffraction (ED-GIXD) system, we evaluated the in-plane structures of the film samples by detecting the 200 reflection from CuPc crystallites. The CuPc molecules subjected to the electric field were found to orient to the different direction from those of the ordinally epitaxially grown films. These facts suggest that the combination of applying voltage and epitaxial growth provide us a new method to control the molecular orientation in the organic thin films.