On electrical and photoconductive properties of mixed Nb2O5/TiO2 sol–gel thin films

Pure TiO2 and mixed Nb2O5/TiO2 oxides were prepared on silica glass substrates using the sol–gel technique. The electrical conductivity of the films, heat-treated at 800 °C, was studied in the temperature range of 27–107 °C in vacuum and in air. The transient photoconductivity was examined in vacuum and in air as a function of temperature and light intensity.The dark conductivity in air was slightly higher than in vacuum. The Nb addition caused a significant increase. The transient photoconductivity of a pure sample was sensitive to the environment and reached very high values. The addition of Nb sharply decreased the photoconductivity.