SURFACE-MORPHOLOGY STUDY OF CORONA-POLED THIN-FILMS DERIVED FROM SOL-GEL PROCESSED ORGANIC-INORGANIC HYBRID MATERIALS FOR PHOTONICS APPLICATIONS

Dye-doped and a dye-attached sol-gel films using the chromophore bis(2 -hydroxyethyl)amino]phenyl}ethenyl)pyridinium tetraphenylborate (BPTP) and thyl)amino-N'-methylstibazoliumtoluene-p-sulfonate (BAST) were fa bricated by sol-gel processing. Surface morphology of the films was st udied using an atomic force microscope. In the dye-doped film, many su rface defects were observed. The morphology of the surface defects var ied as a function of chromophore concentration. The shapes of the defe cts became more complicated as the chromophore concentration increased . On the other hand, no evidence of such defects was present in the dy e-attached sim and the quality of the film was high. Also for the dye- attached film, the surface was optically hat and smooth, and the surfa ce roughness was measured to be less than 4 nm. It was found that coro na poling processes also affected the quality of the dye-attached film significantly. Corona poling with a needle electrode resulted in many irregular shaped defects in the film. However, poling with a tungsten wire stabilized the corona discharge and thus prevented the formation of defects, which led to films of excellent quality. The electro-opti c coefficient, r(33), of the BPTP dye-attached film was measured to be 5.0 pm V-1 and this value was maintained even after 54 days at room t emperature.