Chromium-doped titanium oxide thin films

Undoped and Cr-doped titanium oxide thin films were deposited by using D.C. reactive sputtering technique. The films, deposited onto unheated glass substrates, show an amorphous structure as observed by XRD. SEM, AFM and EPR experiments evidence that Cr-doped samples are nanocrystalline and they are more compact than the undoped films. It was found that, by chromium doping, some parameters (optical transmittance, optical constants and optical band gap) significantly change. The decrease in optical band gap from 3.27 to 2.91 eV, means that the material becomes more absorbing by chromium doping and an extension of its photocatalytic activity to the visible part of the absorption spectrum, can be realized.