Modulation of structural phase, morphology, optical, electrical and magnetic properties of Fe2O3 films by Ag9+, O5+ and Li2+ irradiated ions

Hematite (α – Fe₂O₃) films have been grown on p-Si substrates by using the thermal evaporation method and post-heat treatment at 550 °C to stabilize in the rhombohedral phase. The α – Fe₂O₃ films have been irradiated with Ag⁹⁺, O⁵⁺ and Li²⁺ metal ions to modify the structure and physical properties. The stopping and range of ions in matter (SRIM) simulation has been used to estimate the presence of oxygen vacancies in the films. Apart from the surface amorphization and damages, the irradiation effect has shown a partial transformation of the α-Fe₂O₃ phase into the α-Fe (bcc structure) phase and preferential grain orientation of the films. Rutherford backscattering spectroscopy provided the depth profile of the elemental distribution. It indicated the elemental mixing at the interfaces of the films and substrate. The irradiated films have shown the direct optical band gap in the range of (∼2.2–2.7 eV) and indirect optical band gap in the range of (∼1.29–2.09 eV) in comparison to (∼2.2 eV) for the pristine α – Fe₂O₃ films. The irradiation of Ag, O and Li has enhanced the electrical conductivity up to an order of 10⁻⁴ S/m. The irradiated films exhibited ferromagnetic character in the surface and bulk contributions. The results suggest that the Ag, O and Li irradiated Fe₂O₃ films could be potential candidates for applications in solar cells, magneto-opto-electronic devices, and photodetectors in the deep UV range of radiation.