Orientation and morphology of chloroaluminum phthalocyanine films grown by vapor deposition: Electrical field-induced molecular alignment

Abstract

The electric field influence on the molecular orientation and the surface morphology of the chloroaluminum(III) phthalocyanine (AlClPc) films has been studied using polarization dependent Raman spectroscopy and atomic force microscopy. The experimental studies were supported by DFT quantum chemical computations of the AlClPc vibrational spectra and 15N isotopic shifts. The electric field of 1.4 kV mm −1 applied parallel to the substrate plane during the physical vapour deposition modified the film structure noticeable. The AlClPc molecules were aligned nearly perpendicular to the substrate surface (the mean tilt angle increased to ∼80° from ∼20° in the films grown without the electric field). The AFM images of the AlClPc films grown in the absence of electric field revealed a predominant amount of crystallites of polyhedron shape, whereas in the case of the applied electric field the surface was more ordered and consisted of the crystallites of a smoother shape.