Photoelectrochemical characterization of oxidized films of titanium nitride and titanium obtained by reaction sputtering

Abstract Layers of titanium and titanium nitride obtained by reactive sputtering were studied in 0.5M H 2 SO 4 solution in the domain of potentials from −1000 to 900 mV (SSE) (saturated sulphate electrode) corresponding to the formation of a potentiodynamic passive layer. An irreversible electrochemical formation of an oxide base for the passive layer takes place during the first positive scan. Impedance measurements show a high number of donors and lead to the flat-band potential values. Photocurrent measurements indicate that nitrogen atoms slightly increase the band gap energy but it seems that the gap energies are essentially related to TiO 2 bindings, as are the energetic levels near the band edges. The validity of the Poole-Frenkel model is discussed.