Sol-Gel Processing of Thin Films with Metal Salts

Abstract

Metal salts are a good alternative to metal alkoxides in the sol-gel process. Typically, metal salts are less expensive, and, in some case, metal alkoxides are not available for the desired cation. In forming multicomponent thin films starting with metal salt solutions, a popular approach is called the Pechini method or the modified-Pechini method. In this approach, there is typically a complexing agent or chelating agent. Ethylene glycol and citric acid are a good combination that leads to polymerized gels with stoichiometric amounts of the components. Another common complexing agent is ethylenediamine tetraacetic acid (EDTA). In this way, multicomponent gels with fixed ratios of cations are produced, which lead to multicomponent oxide thin films.