Structural, optical, electrical and dielectrical properties of electrosynthesized nanocrystalline iron oxide thin films

Electrodeposition of semiconducting iron oxide (Fe2O3) thin film was carried out from an alkaline sulphate bath. A 0.1 M ferrous sulphate (FeSO4·7H2O) was complexed with 0.1 M citric acid. By addition of 1 N NaOH, pH of the solution was made alkaline (pH=9) and deposition of iron oxide (Fe2O3) thin films was carried out potentiostatically at room temperature (300 K). From cyclic voltametry (CV), electrochemical studies were carried out for deposition of iron oxide thin films. The XRD studies reveal that Fe2O3 with epsilon (ε) phase having monoclinic crystal structure is formed. By observing scanning electron microscope (SEM), it is seen that iron oxide films were homogeneous, uniform and well covered to surface of the substrate. Grain size was found to be in nanometers range from XRD analysis. The optical band gap of Fe2O3 thin film was estimated to be 1.90 eV. Electrical resistivity was order of 104 Ω cm. Dielectric constant and loss (tan δ) were found to be frequency dependent.