Investigation and characterization of radio frequency sputtered Cr1.8Ti0.2O3−δ thin films derived by citrate, sol–gel and solid state routes

Cr1.8Ti0.2O3−δ (CTO) powders were prepared by citrate, sol–gel and solid-state routes, respectively. The effect of preparation methods on the morphology of sputtered thin films was further investigated. X-ray diffraction patterns of the powders and films confirmed a single phase CTO. No impurity was observed even after sintering the powders at 1000 °C for 24 h. X-ray photoelectron spectroscopy analysis showed that Cr 2p (577.8 eV), and O 1 s (531.5 eV) core levels of the sputtered films have ∼1 eV variation in their binding energy positions compared to those of CTO powders. The atomic force microscopy analysis showed the grains of the films obtained by sputtering sol–gel powders had the smallest size in the range of 7–58 nm. The surface roughness of the thin films had the lowest value at 0.70 nm, whereas those obtained from solid state solution had the maximum value of 2.51 nm.