Synthesis, surface tension, optical and dielectric properties of bismuth oxide thin film

Bismuth oxide thin film was deposited by chemical bath deposition (CBD) technique onto a glass substrate. The grain size (D), dislocation density (δ) and number of crystallites per unit area (N), i.e. structural properties of the thin film were determined as 16 nm, 39.06× 10^–4 line/nm², 31.25 × 10^–3 1/nm², respectively. Optical transmittance properties of the thin film were investigated by using a UV-Vis spectrophotometer. The optical band gap (E_g) for direct transitions, optical transmission (T %), reflectivity (R %), absorption, refractive index (n_r), extinction coefficient (k), dielectric constant (∊) of the thin film were found to be 3.77 eV, 25.23 %, 32.25 %, 0.59, 3.62, 0.04 and 2.80, respectively. The thickness of the film was measured by AFM, and was found to be 128 nm. Contact angles of various liquids on the oxide thin film were determined by Zisman method, and surface tension was calculated to be 31.95 mN/m.