Acentric films of 4-[trans-(pyridin-4-ylvinyl)] benzoic acid (PVBA) are grown on amorphous substrates by oblique incidence organic molecular beam deposition. The molecules in the bulk of the films show a preferential noncentrosymmetric in-plane orientation determined by the molecular beam direction. We investigate this symmetry-breaking mechanism by studying the structural and nonlinear optical properties of the films as a function of deposition conditions, with special focus on the molecular beam angle of incidence. The most pronounced preferential orientation of the molecules is found for an incident angle of 50±10 deg relative to the substrate normal.
© 2004 Optical Society of America
Axelle Tapponnier, Erik Delvigne, Ivan Biaggio, and Peter Günter, "Nonlinear optical and structural properties of noncentrosymmetric organic thin films obtained by oblique incidence molecular beam deposition," J. Opt. Soc. Am. B 21, 685-690 (2004)