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 deg. 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