Elaboration of nanostructured TiO2/SiO2 films by plasma enhanced chemical vapor deposition at atmospheric pressure

This paper reports a rapid and simple method for the co-deposition of TiO2/SiO2 films, using a microwave plasma torch and organometallic precursors. Both structure and microstructure of the films have particularly been investigated. The results show that the characteristics of the deposits mainly depend on the torch to substrate distance (d). When this distance is short (d = 10 mm), the co-deposits are quite dense and exhibit crystalline TiO2 phases. By contrast, when d = 30 mm, the co-deposits are amorphous. At d = 30 mm, it was also shown that silica could act as an encapsulation matrix for titania particles in only one step. Moreover, for d = 30 mm, the adjunction of silica, about 40 mol% allows enhancing the adherence of the films, whereas pure titania deposits are not adherent at all.