Engineering the Microstructure and Functional Properties of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 Thin Films
Auteurs
Konsago S.W., Žiberna K., Matavž A., Mandal B., Glinšek S., Fleming Y., Benčan A., Brennecka G.L., Uršič H., Malič B.
Référence
ACS Applied Electronic Materials, vol. 6, n° 6, pp. 4467-4477, 2024
Description
Lead-free piezoelectric 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) thin films deposited by chemical solution deposition on platinized silicon substrates using ethylene glycol and ethanol solvents for alkaline-earth carboxylates and transition-metal alkoxides, respectively, are studied. Undoped and manganese-doped BZT-BCT films prepared by repeated deposition of a 0.1 M precursor solution and multistep annealing at 850 °C until reaching the thickness of about 120 nm exhibit a predominantly columnar microstructure with preferential (111) orientation of the perovskite phase. The Mn-doped films’ room-temperature permittivity is about 670 at 1 kHz, which is ≈30% higher than the permittivity of their undoped counterparts at the same frequency and temperature while maintaining a similar tan δ ≈ 0.02. Mn-doping effectively reduces the leakage of BZT-BCT films, contributing to a saturated ferroelectric hysteresis loop with a remnant polarization of 5 μC cm-2 and a coercive field of 80 kV cm-1. The maximum polarization and recoverable energy storage density are about 32 μC cm-2 and 10 J cm-3, respectively, with 69% efficiency at 1160 kV cm-1. The energy-storage properties remain almost unaffected after 2 million cycles at a field of 800 kV cm-1. The piezoelectric d33 coefficient measured by double-beam laser interferometry is about 20 pm V-1, while the corrected value of d33 ≈ 34 pm V-1 taking into account the ratio of the electrode size to substrate thickness being equal to unity.
