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

Abstract

Herein, we have investigated the optical and microwave dielectric properties of Bi0.5Na0.5TiO3 (BNT) thin films grown under different oxygen pressure (PO2) using pulsed laser deposition (PLD) technique. The X-ray diffraction measurements confirms the single phase of BNT along with secondary phase and further reduction in secondary phase and increase in BNT phase with PO2, signifies the close relation between the crystal structure and oxygen content.The shift of Raman-active TO1, TO2 and TO3 modes towards higher wavelengths and increase in mode intensity with PO2 indicating the films degree of crystallinity. The local roughness (αloc) of all films obtained as  0.85, and the interface width () and lateral correlation length (ξ) of films varies with PO2. Also, the films exhibit the increase in refractive index and reduction in optical bandgap of due to improvement in crystallinity and reduction in the oxygen vacancies. The microwave dielectric properties show a strong PO2 depends with higher dielectric constant (εr = 336) with lower loss (tanδ = 0.0093) at 5 GHz which show the potential applications in high frequency devices.