Ordered growth and crystal structure of Alq(3) on alkali halide surfaces

Ordered films of tris-8-hydroxyquionolate-aluminum (Alq(3)) were grown by m olecular beam deposition on cleaved KCl and KBr surfaces. The local molecul ar arrangements in the films were characterized by two-dimensional analysis of multiazimuth reflection medium energy electron diffraction (RMEED). A n ew type of curved one-dimensional crystallographic ordering was observed on KBr while a continuous point-on-line-type ordering was observed on KCl. Gr owth of the crystals consisting of mer isomers is suggested from the observ ed triple period superstructure.