Preparation and Characterization of Nanocrystalline α-Fe₂O₃ Thin Films Grown by Successive Ionic Layer Adsorption and Reaction Method

摘要

Nanocrystalline α-Fe₂O₃ thin films were deposited by successive ionic layer adsorption and reaction method onto glass substrates. The X-ray diffraction study revealed that α-Fe₂O₃ films are nanocrystalline in nature with rhombohedral structure. The morphological investigations were carried out by using field emission scanning electron and atomic force microscopy studies. The random distribution of α-Fe₂O₃ nano-grains with agglomeration is observed on the substrate surface. The room temperature electrical resistivity of α-Fe₂O₃ film is of the order of 9.46 ×10² Ω cm. The thermo-emf measurements confirmed n-type semiconducting nature of SILAR grown α-Fe₂O₃ films. The optical absorption measurements showed that α-Fe₂O₃ exhibits direct and indirect band gap energies of the order of 1.92 and 2.97eV respectively. These encouraging results make preparation of α-Fe₂O₃ by SILAR method useful in the development of optoelectronic devices such as sensing and photovoltaic devices.