Fluorine-doping in titanium dioxide by ion implantation technique

Abstract

We implanted 200 keV F + in single crystalline titanium dioxide (TiO 2) rutile at a nominal fluence of 1 × 10 16 to 1 × 10 17 ions cm −2 and then thermally annealed the implanted sample in air. The radiation damage and its recovery process during the annealing were analyzed by Rutherford backscattering spectrometry in channeling geometry and variable-energy positron annihilation spectroscopy. The lattice disorder was completely recovered at 1200 °C by the migration of point defects to the surface. According to secondary ion mass spectrometry analysis, the F depth profile was shifted to a shallower region along with the damage recovery and this resulted in the formation of an F-doped layer where the impurity concentration steadily increased toward the surface. The F doping proved to provide a modification to the conduction-band edge of TiO 2, as assessed by theoretical band calculations.