The results of combined IR absorption and photoconductivity studies on hydrogen donors in ZnO and TiO2
are presented. It is shown that hydrogen donors in ZnO and rutile TiO2 can be detected as Fano resonances
in the photoconductivity spectra at the frequencies corresponding to the vibrational modes of these defects.
In the case of anatase TiO2 IR absorption lines at 3412 and 3417 cm−1 are assigned to the stretching local
vibrational modes of a donor in the neutral and the positive charge states, respectively. Interstitial hydrogen
is suggested as a tentative model for the defect giving rise to these vibrational modes.