Figure 4From: Influence of transition metal doping on the structural, optical, and magnetic properties of TiO2 films deposited on Si substrates by a sol–gel processNormalized and fitted XPS core level spectra of oxygen 1 s level. Normalized XPS core level spectra of oxygen 1 s level of undoped and Co-doped TiO2(a). Fitted XPS core level spectra of oxygen 1 s level of TiO2 film (b), Ti0.99Co0.01O2 film (c), and Ti0.97Co0.03O2 film (d).Back to article page