ELECTRICAL-PROPERTIES OF CR-DOPED AND NB-DOPED TIO2 THIN-FILMS

The series of thin films of solid solutions of TiO2 + xCr2O3 (0 < x < 0.013) and TiO2 + yNb2O5 (0 < y < 0.05) were deposited on fused silica by means of reactive RF co-sputtering. The obtained films remain in the amorphous state up to 673 K. Annealing at 1173 K produces a well-developed rutile structure while formation of the anatase structure has not been observed. The high temperature electrical properties such as electrical conductivity, thermopower and work function were investigated within the wide range of oxygen activity (10(-10)-10(5) Pa). The effect of both Cr and Nb concentrations and film thickness on the measured parameters was studied. A mechanism for the incorporation of dopants (Cr and Nb) and defect model has been proposed. The influence of both intrinsic and extrinsic defects on the electrical properties has been discussed. The distribution of main elements (Ti, Si, O) as well as impurities were determined by the SIMS method.