Investigation of surface scaling, optical and microwave dielectric studies of Bi0.5Na0.5TiO3 thin films

Herein, we have investigated the optical and microwave dielectric properties of Bi 0.5 Na 0.5 TiO 3 (BNT) thin films grown under different oxygen pressure (PO 2 ) using the pulsed laser deposition technique. The X-ray diffraction measurements confirm the single phase of BNT and the secondary phase and a further reduction in the secondary phase and increase in the BNT phase with PO 2 , which signifies the close relationship between the crystal structure and oxygen content. The shift of Raman-active TO 1 , TO 2 , and TO 3 modes towards higher wavelengths and increase in mode intensity with PO 2 indicating the degree of the film of crystallinity. The local roughness ( α loc ) of all films obtained as ∼ 0.85 and the interface width ( ω ) and lateral correlation length ( ξ ) of films vary with PO 2 . Also, the films exhibit an increase in refractive index and reduction in the optical bandgap due to improvement in crystallinity and reduction in the oxygen vacancies. The microwave dielectric properties show that a strong PO 2 depends on the higher dielectric constant ( ε r = 336) with lower loss (tan δ = 0.0093) at 5 GHz, which shows the potential applications in high-frequency devices.