Controlling geometric and electronic properties of highly ordered CuPc thin films

Geometric and electronic properties of ordered copper phthalocyanine (CuPc) thin films grown on hydrogen- and antimony-passivated Si(1 1 1) surfaces have been studied using near edge X-ray absorption fine structure (NEXAFS) and photoemission spectroscopy. The H- and Sb-passivations of vicinal Si surfaces resulted in different molecular orientations in thick films, namely upright and near lying molecules, respectively. In the absence of the vicinality, the molecules on the Sb-passivated surface changed towards upright orientation. The work function of the films was monitored during the growth and correlated with the molecular orientation.