Optical and Electrical Characterizations of Ultrathin Films Self-Assembled from 11-Aminoundecanoic Acid Capped TiO₂Nanoparticles and Polyallylamine Hydrochloride

11-Aminoundecanoic acid capped titanium dioxide (capped-TiO 2 ) nanoparticles (63 ± 2 Å total diameter and 20−24 Å core diameter) and polyallylamine hydrochloride, PAH, have been layer-by-layer self-assembled onto precoated (by poly(diallyldimethylammonium chloride), PDDA, or PAH) substrates. The ultrathin S-PDDA(capped-TiO 2 /PAH) n ( n = 5, 10, 15) films have been characterized by absorption and surface plasmon spectroscopies, cyclic voltammetry, and scanning force microscopy. A S-PDDA(capped-TiO 2 /PAH) 10 film coated by a layer of gold has been shown to function as a Schottky diode.