Studies on phase transformations of Cu-phthalocyanine thin films

Copper phthalocyanine (CuPc) thin films were obtained by a sublimation technique on Si wafer substrates maintained at room temperature. As-deposited CuPc films with less than 0.1 mu m thickness crystallize primarily in the alpha-form with a preferential orientation of the crystallites in the [2 0 0] direction. The effect of randomizing of the orientation of the CuPc crystallites is observed as the film thickness increases, whereas the preference in appearance of the alpha-form remains. The changes in phase composition, structure, morphology and surface chemical composition of as-deposited CuPc thin films due to different heat treatment conditions were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS).