Effect of substrate temperature on the optical properties of CaBi4Ti4O15 thin films deposited by pulsed laser ablation

Thin films of CaBi 4 Ti 4 O 15 (CBTi) were deposited at different substrate temperatures (550–700 °C) using pulsed laser ablation technique. Structural, morphological and linear optical properties of the same were investigated. The CBTi thin films crystallize above 550 °C and forms single phase is confirmed by XRD and Raman spectroscopy. The lattice strain induced during deposition, controls the unit cell volume, grain size and crystallite size. The refractive index, real and imaginary parts of optical dielectric constant and optical band gap were extracted from transmission spectra (190–2500 nm). Tauc’s plot confirmed the direct band gap nature ranging from 3.4 to 3.6 eV. The study on CBTi thin films and their optical properties opens up a new window for optical applications.