Investigations of Sputtered Thin Film TiO2 Electrodes with Low Donor Densities

The photoelectrochemical behavior of sputtered low‐doped titanium oxide electrodes was investigated and compared with low‐doped single‐crystal material. All low donor density electrodes yielded anodic and cathodic photocurrents upon illumination with bandgap light. The photoresponse spectra are characterized by two apparent current maxima centered around 380 and 300 nm. It is suggested that the low‐doped sputtered oxide acts as a photoconductor with a nearly linear photocurrent/potential dependence in a limited potential range, or as a photosemiconductor depending on doping of the material and on the wavelength of illumination. The occurrence of two maxima in the photoresponse spectra is attributed to the inhomogeneous layered structure of the sputtered electrodes.