14. Chemical Bath Deposition

Chemical bath deposition encompasses a variety of routes for producing functional oxide films and coatings at relatively low temperature by immersing a substrate in a liquid solution. Films of dozens of single- and multi-component oxide materials have been synthesized, mostly from aqueous precursor solutions, at temperatures below 100 °C, and on substrates that vary widely in their chemistries and topographies. This chapter focuses on three aspects of the chemical principles that govern the formation of such films. The first aspect is solution chemistry: the interrelated effects of solution temperature, pH, and concentration needed to generate the oxide material, and which influence all subsequent considerations of the film deposition process. The second aspect is the interactions between the substrate and the growing film, which can be utilized to promote or suppress film attachment and to control the microstructure and spatial distribution of the film. The third aspect addresses practical considerations of a deposition process, such as design factors (other than solution parameters) that affect growth rates and film thicknesses. The chapter concludes with a discussion of the limitations of CBD processes for oxide film synthesis, and of the most promising potential applications and areas for future research.