Atomic/molecular layer deposited thin-film alloys of Ti-4,4′-oxydianiline hybrid–TiO2 with tunable properties

Abstract

By combining atomic layer deposition (ALD) and molecular layer deposition (MLD) thin-film techniques, the latter being a variant of the former in which organic precursors are used, it is possible to deposit thin films containing precisely controlled portions of inorganic and organic constituents. This in turn enables the adjustment of material properties by changing the number of ALD and MLD cycles applied during the deposition. In this work, the properties of such thin-film “alloys” prepared by varying the portions of Ti-4,4′-oxydianiline (Ti-ODA) inorganic–organic hybrid and TiO₂ in the structure were investigated. The films were deposited at 280 °C using TiCl₄ and water as precursors for TiO₂, and TiCl₄ and ODA for the Ti-ODA hybrid. The results demonstrate excellent tunability of the film properties such as degree of crystallinity, roughness, refractive index, and hardness depending on the relative number of TiO₂ and Ti-ODA cycles employed.