Relationship between precursor chemistry and microstructure of CSD derived PZT films

Abstract
The microstructure of CSD PZT based thin films is mainly controlled by the substrate, electrode and/or thermal treatment. However, it can be significantly altered by the choice of starting compounds and solution-precursor synthesis conditions. The choice of transition metal alkoxide, namely propoxide or butoxide in the methoxyethanol based PZT route, results in different reactions with lead acetate. While the propoxides predominantly react via the addition reaction, the esterification reaction is predominant for butoxides. A finer microstructure of PbZrO₃ films is attained from propoxides and a coarser one starting from butoxides. Lead acetate can be replaced by lead oxide in the methoxyethanol based PZT route. The crystallisation of the latter is characterised by easy nucleation of the perovskite phase as compared to acetate derived films. The type of lanthanum precursor, i.e. acetate or nitrate in the acetic acid based CSD PLZT route, influences the functional group content of formamide modified sols and consequently affects the microstructure of the thin films. La-nitrate based films consist of about 100 nm sized grains and La-acetate ones are characterised by the cluster-type microstructure.