Rutherford backscattering and channeling studies of a TiO2(100) substrate, epitaxially grown pure and Nb-doped TiO2 films

We have investigated the crystalline quality of a TiO2(100) substrate, homoepitaxially grown TiO2 film and Nb-doped TiO2 films using Rutherford backscattering (RBS) and channeling experiments. The minimum yields obtained from the aligned and random spectra are 2.4 ± 0.2% for the TiO2(100) substrate, and 4.0 ± 0.2% for a homoepitaxial TiO2 film. The minimum yields for Ti and Nb are 1.6 ± 0.2% and 7.0 ± 1.0%, respectively, for a Nb-doped TiO2 film. Also, about 95% of the Nb atoms occupy cation sites in the Nb-doped TiO2 film. The angular yield curves for Ti and Nb from the Nb-doped film confirm the good crystalline quality of the film in which most Nb atoms occupy the cation sites. The calculated surface peak areas for Ti and Nb using a model which incorporates Nb surface segregation from the bulk, agree very well with the corresponding surface peak areas for Ti and Nb extracted from the experiment.