Effect of substrates on the molecular orientation of silicon phthalocyanine dichloride thin films

Deng, J.; Baba, Yuji  ; Sekiguchi, Tetsuhiro  ; Hirao, Norie*; Honda, Mitsunori   

Molecular orientations of silicon phthalocyanine dichloride (SiPcCl) thin films deposited on three different substrates have been measured by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. For thin films about 5 monolayers, the polarization dependences of the Si K-edge NEXAFS spectra showed that the molecular planes of SiPcCl on three substrates were nearly parallel to the surface. Quantitative analyses of the polarization dependences revealed that the tilted angle on HOPG was only 2 degree, which is interpreted by the perfect flatness of HOPG surface. While the tilted angle on indium tin oxide (ITO) was 26. It is concluded that the morphology of the top surface layer of the substrate affects the molecular orientation of SiPcCl molecules not only for mono-layered adsorbates but also multi-layered thin films.