Improving functional properties in Cr₂O₃ thin films through annealing: a route toward sustainable materials engineering

Cr₂O₃ thin films were deposited by DC magnetron sputtering under varying oxygen flow rates to investigate the influence of oxygen content and annealing effect on their structural and electronic properties. XRD and Raman confirmed pure phase Cr₂O₃ with improved crystallinity and reduced lattice strain after annealing. XPS analysis indicated predominant Cr³⁺ states with oxygen defects that decreased upon annealing, showing chemical stability. The Schottky diode current-voltage analysis demonstrated rectification, with thermionic emission and Norde models confirming reduced ideality factor, series resistance, and a stabilized barrier height (~ 0.78 eV). The Mott-Gurney space charge limited conduction model was used to determine mobility and trap density in the deposited films. Dielectric studies revealed that the thermal annealing suppressed polarization, lowered the dielectric loss, enhanced the AC conductivity and reduced Nyquist arc diameters.