Lattice disorder distribution and recovery in Hg implanted TiO2

The damage distribution of ion implanted crystalline oxides often reveals two subpeaks, one near the surface and one near the mean projected range, R(p), of the implanted ions. For Hg implanted TiO2 (rutile) single crystals two well separated peaks were observed for [001], [111] and [100] oriented crystals. Implantations at 77 K and 300 K, followed by annealing experiments were performed to study the mechanisms of near surface peak formation. It was shown that this peak is exactly located at the surface. Long range atomic migration and pinning at the surface as well as changes of the composition by preferential oxygen sputtering could be excluded as sources of surface damage peak formation. A recovery of this peak was not observed below 300 K, in contrast to the damage near R(p), which recovered by about 65%. Recovery of both subpeaks were noted, however, at temperatures of 500 K and above.