Influence of Cu ions on the photo-transport properties in KTaO3:(Cu,V) single crystals.

Photoconductivity kinetics, temperature dependence and excitation spectra were measured in the intervals 15-300 K and 2-4.2 eV in KTaO3:(Cu,V) single crystals processed by oxidation/reduction treatments. The kinetics, excited by band-gap excitation, present very slow saturation times, while faster time responses were observed using excitation below the band-gap. The oxidized crystal exhibited higher photoconductivity when Elight > 3 eV. Linear dependence on light intensity was measured, suggesting one center recombination processes. Optical absorption at room temperature was checked as complementary informatio