Two stage formation of silver nanoparticles in PZT thin films controlled by re-nucleation through transition phase of Ag-Pb alloy

• Ag nanoparticle-PZT film with high dielectric properties is successfully prepared.
• Lead-rich Ag-Pb alloy particles formed in the thin film in the first stage.
• Ag nanoparticles formed through re-nucleating from lead-rich Ag-Pb alloy particles.

Ag nanoparticles were formed in PbZr0.52Ti0.48O3 (PZT) thin films by the sol–gel technique through two stage processes. In the first stage, Ag-Pb alloy particles formed in all film heat treated for different time from 1 min to 10 min. The average size of the particles increased from 0.16 μm to 0.43 μm while the mole ratio of Pb/(Pb + Ag) in the alloy particles increased from 0.7% to 27%. After that in the second stage with the heat treatment time above 10 min, the lead rich Ag-Pb alloy particles started to decompose gradually. The silver nanoparticles formed in the thin film to form nano-Ag/PZT composite. The number of the silver nanoparticles of about 6 nm in size increased with increasing the heat treatment time from 20 min to 180 min. The permittivity and tunability of the nano-Ag/PZT composite thin film were 120% and 46% higher than those of the PZT thin film without Ag nanoparticles, respectively.