Doping TiO
2 with nitrogen is recognized as a procedure to get sensitization of this material with visible light.In the present work, incorporation of nitrogen within the structure of TiO
2 thin films has been accomplishedby N
2+ ion implantation in TiO
2 anatase thin films (50 keV ion ener
gy for doses of 3 × 10
16, 6 × 10
16, and1.2 × 10
17 ions cm
-2) and during preparation by metalorganic chemical vapor deposition (MOCVD) usingnitrogen as carrier gas. The analysis of the samples by X-ray photoemission spectroscopy (XPS) and for theMOCVD samples also by secondary ion mass spectroscopy (SIMS) has shown that nitrogen, in the form ofnitride-like species, (N/Ti ratios of 0.03 and 0.12 for the MOCVD and the implanted samples, respectively)has become effectively incorporated within the structure of TiO
2. The water contact angle on the implantedthin films varied from about 80
![](/images/entities/deg.gif)
to around 30
![](/images/entities/deg.gif)
when illuminated with visible light, depending on the iondose. Similarly, the MOCVD samples showed a sharp decrease in wetting contact angle under visible lightfrom about 80
![](/images/entities/deg.gif)
to 55
![](/images/entities/deg.gif)
. In the two cases, the thin films reach total hydrophilicity by posterior UV irradiation.To account for these results, the possible existence of specific excitation mechanisms for visible or UV photons,the former involving the incorporated nitrogen atoms, is discussed.