Improved Electrical Properties of Cr-Doped K_0.5Bi_4.5Ti₄O₁₅ Thin Films Fabricated by Chemical Solution Deposition

Abstract

Ferroelectric K_0.5Bi_4.5Ti₄O₁₅ (KBTi) and Cr-doped K_0.5Bi_4.5Ti₄O₁₅ ((K_0.5Bi_4.5Ti_3.97 Cr_0.03O_15-δ), (KBTC)) thin films were prepared on Pt(111)/Ti/SiO₂/Si substrates by using a chemical solution deposition method. The thin films were annealed at 750°C for 3 min by a rapid thermal annealing process under oxygen atmosphere. Compared to pure KBTi thin film, there was no structural change while improved ferroelectric and leakage current properties were observed. The values of remnant polarization (2P_r ) and coercive field (2E_c ) were 50.9 μC/cm² and 244 kV/cm at an applied electric field of 300 kV/cm, respectively. The 2P_r we observed is compatible with that of doped bismuth layer-structured ferroelectric thin films. Leakage current density was 6.00 × 10⁻⁷ A/cm² at 200 kV/cm. The enhanced properties of KBTC could be explained by a defect dipole (Cr′_Ti-V) and increased average grain size.

Keywords:

• Cr-doped K_0.5Bi_4.5Ti₄O₁₅ thin film
• electrical properties
• chemical solution deposition

Acknowledgments

This work was supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) (2010-0029634) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) (2010-0007494) funded by the Ministry of Education, Science and Technology.