EPITAXIAL-GROWTH OF NONLINEAR-OPTICAL 4'-NITROBENZYLIDENE-3-ACETAMINO-4-METHOXY-ANILINE THIN-FILMS ON ETHYLENEDIAMMONIUM TEREPHTHALATE SINGLE-CRYSTALS

Thin layers of nonlinear optical 4'-nitrobenzylidene-3-acetamino-4-met hoxy-aniline (MNBA) were grown heteroepitaxially by organic molecular beam epitaxy (OMBE) on the b-plane of lattice-matched single crystals of the organic salt ethylenediammonium terephthalate (EDT). Epitaxy wa s realized at a substrate temperature of 80 degrees C and moderate gro wth rates of 0.1-0.2 Angstrom/s. Optical microscopy showed formation o f oriented elongated islands aligned normally to the [001] direction o f the substrate. The in-plane orientation of the MNBA overgrowth coinc ided with that of the EDT surface. Second harmonic generation (SHG) ex periments showed as theoretically expected a cos(4) theta dependence o n the angle theta of the linear polarization of the fundamental beam f or an oriented MNBA thin film.