Structure, optical, and magnetic properties of facing-target reactive sputtered Ti1-xFexO2-δ films

Structure, optical, and magnetic properties of the anatase Ti1-xFexO2-delta films fabricated by facing-target reactive sputtering were investigated. Structural analyses indicate that there are no impurity phases in the films and the grain size reaches maximum when Fe content x is 0.017. The optical band gap of the Ti1-xFexO2-delta films decreases with the increasing x. Photoluminescence (PL) spectra show that direct and indirect band-to-band transitions coexist, and the indirect radiative recombination can be regarded as a one photon and two phonon coupling courses. The PL intensity due to oxygen vacancies enhances and the refractive index of the fims increases with the increasing x. The Ti1-xFexO2-delta films exhibit room-temperature ferromagnetism due to the oxygen vacancies.