Influence of annealing temperature and electrical conductivity of α-Fe₂O₃ nanoparticles for Schottky barrier diode

The microwave irradiation route is adopted for synthesizing hematite nanoparticles. The occurrence of different stages in iron oxide nanoparticles due to annealing temperature is validated from its phase transition. The temperature variation for annealing process is made subsequently in this experiment in steps of 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C and 900 °C. The formation and deformation of α-Fe₂O₃ (hematite) phase is identified from this work. The morphology, crystallinity and consistency in particles size are estimated from XRD, SEM and TEM image. The decrease in particle size is due to phase transformation which is identified from 78 to 24 nm. The specified involvement of thermal stability is tested from TGA analysis which is confirmed from phase transition in the XRD. Change in bandgap energy and respective blue shift for less particle sizes are elucidated from UV-DRS and PL spectra. The elemental presence Fe 2p and O 1s spectra indicates the valence states of Fe³⁺ and O²⁻ from XPS and the VSM results are confirmed according to the increase in saturation and decrease in coercivity tended towards soft magnetic behaviour due to phase transition. The DC electrical conductivity and activation energy are calculated from I–V studies. The Schottky barrier diode parameters of ideality factor (n), barrier height (Φ_b) and reverse saturation current (I₀) is calculated for both dark and light conditions.