Impact of NiO_<i>x</i> Buffer Layers on the Dielectric Properties of BaTiO₃ Thin Films on Nickel Substrates Fabricated by Polymer Assisted Deposition

Abstract

Structural health monitoring with piezoelectric thin films integrated on structural metals shows great advantages for potential applications. However, the integration of piezoelectric thin films on structure metals is still challenged. In this paper, we report the piezoelectric barium titanate [BaTiO 3 (BTO)] thin films deposited on polycrystalline Ni substrates by the polymer assisted deposition (PAD) method using NiO x as the buffer layers. The NiO x buffer layers with different thicknesses were prepared by varying immersing time from 5 minutes to 4 hours in H 2 O 2 solution. The dielectric and leakage current properties of the thin films have been studied by general test systems. The BTO/Ni heterostructure with 2‐hour immersing time exhibits better dielectric properties with a dielectric constant over 1500 and a 34.8% decrease of the dielectric loss compared to that with 5‐minute immersing time. The results show that the leakage current density is strongly affected by the thickness of the NiO x buffer layer. The conduction mechanisms of the BTO/Ni heterostructure have been discussed according to the J ‐ V characteristic curves.