RBS/channeling analysis of damage and annealing processes of Nb-implanted TiO2

Single crystalline TiO2 (0 0 1) was implanted with Nb+ ions RT (room temperature) and at 130 K to the doses of 1.1 x 10(16) and 0.9 x 10(16) Nb/cm(2), respectively. The damage and its recovery processes during isochronal annealing were analyzed by the RBS/channeling method. As a result, the TiO2 crystal was found to be amorphized by 130 K implantation while a crystalline part remained after RT-implantation. The partially damaged layer produced by RT-implantation almost recovered with one annealing stage at 500 degrees C. The layer amorphized by 130 K implantation showed two annealing stages, i.e., 300-600 degrees C and above 800 degrees C. Between these two stages, 800 degrees C annealing made the substitutionality of Nb decrease to almost 0%, which suggests a phase transition of the crystal. After annealing at 1200 degrees C, the mixed oxide of NbxTi1-xO2 was formed in either sample, which was confirmed by RBS angular scan measurement and XPS analysis. (C) 1998 Elsevier Science B.V.