Influence of the annealing temperature of the Bi4Ti3O12 seeding layer on the structural and electrical properties of Bi3.15Nd0.85Ti2.99Mn0.01O12 thin films

Abstract

Highly (117)-preferred Bi_3.15Nd_0.85Ti_2.99Mn_0.01O₁₂ (BNTM) thin films with a Bi₄Ti₃O₁₂ (BTO) seeding layer were fabricated on Pt(111)/Ti/SiO₂/Si(100) substrates by using a sol–gel method. The effects of the Bi₄Ti₃O₁₂ (BTO) seeding layer under different annealing temperatures ranging from 550 to 700 °C on the structural and electrical properties of BNTM were investigated. X-ray diffraction results indicated that the BNTM thin films with a BTO layer processed with the annealing temperature of 600 °C exhibited the highest (117) orientation at a degree of 97.33%. This typical BNTM film also had the largest remanent polarization (2P_r = 114.5 μC cm⁻²), dielectric constant (ε_r = 614.9) and dielectric tunability (16.9%) as compared to the BNTM thin films without a seeding layer or with the BTO layer processed at a different temperature. It is also found that the significant enhancement of the piezoelectric properties was achieved in these typical BNTM thin films. Additionally, the BNTM thin films with BTO seeding layers displayed better fatigue properties, degraded by only 1.1% after 10⁹ pulse cycles as compared to 30.2% for those without seeding layers. The mechanism of the temperature dependence of BTO seeding layer on the properties of BNTM will be discussed.