The effect of oxygen partial pressure on the properties of CuFeO2 thin films prepared by RF sputtering

Single phase CuFeO2 thin films with c-axis orientation were prepared by RF sputtering method at room temperature under oxygen partial pressure PO from 5% to 15% and then post annealed at 900 °C for 4 h in flowing N2 atmosphere. The grains of the films show layer-by-layer structure and are closely gathered and densely arranged. The Eg at near-UV region shows a redshift with increment of PO which may due to the impurity levels induced by oxygen interstitials. The resistivity of the films first decreased and then increased with increasing PO. The minimum resistivity of 0.32 Ωcm at room temperature for the sample 10%-PA is nearly two-order magnitude smaller than that (18 Ωcm) for 5%-PA. Oxygen interstitial doping can effectively enhance the conductivity of CuFeO2 thin films.