Influence of Substrate Temperature on the Structural and Optoelectronic Properties of BiFeO ₃ Thin Films

Abstract Bismuth ferrite, BiFeO 3 (BFO) thin films were successfully deposited onto indium tin oxide (ITO) glass substrates at different substrate temperatures such as 200 °C, 300 °C, and 400 °C using thermal evaporation technique. The results were analyzed to make use the films for potential device applications. The X‐ray diffraction (XRD) results confirmed the formation of a rhombohedral perovskite phase structure. Using Scherrer's relation the crystallite size was calculated, and the average crystallite size was 39 nm. From the SEM micrographs it was observed that the films were uniform, crack free with well denied grains. The optical properties were studied using UV–Vis‐NIR spectrophotometer. The films exhibited high optical absorption in the visible region and shown a band gap of 2.2 eV. The average film thickness was measured using a stylus Ellipsometer and it was 264 nm. The chromaticity diagram CIE (Commission Internationale de l'Éclairage) provides a quantitative validation of the blue light‐emitting nature of the thin film, suggesting its potential for applications in light emitting diode (LED) devices. BFO thin films grown at a substrate temperature of 400 °C possess desired physical properties for the use in photovoltaic devices, memory storage, and spintronic systems, paving the way for further exploration of their multifunctional capabilities.