Size Dependent Physical Properties of Nanostructured α-Fe2O3 Thin Films Grown by Successive Ionic Layer Adsorption and Reaction Method for Antibacterial Application

Thin films of nanostructured α-Fe2O3 with thickness of 156, 203 and 251 nm were deposited by successive ionic layer adsorption and reaction (SILAR) method onto glass substrates using FeCl3·6H2O and NaOH as cationic and anionic precursors. The X-ray diffraction studies revealed that, α-Fe2O3 thin films are nanocrystalline in nature with rhombohedral structure. The morphological properties were investigated by field emission scanning electron and atomic force microscopy. The optical studies showed that α-Fe2O3 exhibits direct as well as indirect optical band gap energy. The electrical resistivity of α-Fe2O3 at 305 K decreases from 11.76 × 102 to 9.46 × 102 Ω cm as film thickness increases from 156 to 251 nm. The thermo-emf measurements confirmed that α-Fe2O3 exhibits n-type conductivity. The nanocrystalline α-Fe2O3 exhibits antibacterial character against Staphylococcus aureus and its efficiency increases from 37.50% to 87.50% depending on crystallite size.