Review: deposition of ceramic thin films at low temperatures from aqueous solutions

Several techniques for the synthesis of ceramic thin films from aqueous solutions at low temperatures (25–100 °C) have been reported. This paper reviews non-electrochemical, non-hydrothermal, low-temperature aqueous deposition routes. Originally used for sulfide and selenide thin films, such techniques have also been applied to oxides since the 1970s. Films of single oxides (e.g. transition metal oxides, In2O3, SiO2, SnO2) and multicomponent films (doped ZnO, ferrites, perovskites) have been produced. The maximum thicknesses of the films obtained have ranged from 100 to 1000 nm, and deposition rates have ranged from 2 to 20,000 nm/h. Advantages and limitations of these techniques are discussed. This review groups the reported techniques into four main categories, based on distinctions in the solution chemistry used: chemical bath deposition (CBD), selective ion layer adsorption and reaction (SILAR), liquid phase deposition (LPD), and electroless deposition (ED). Then the paper discusses variations on the main techniques—ferrite plating, liquid flow deposition, the use of functionalized surfaces, photochemical deposition, and the use of external forces or fields—which significantly expand the capabilities of the main techniques.