Abstract
We report measurements of the diffusion rate of isolated ion-implanted within of the surface of oriented single-crystal rutile using a radiotracer technique. The particles from the decay provide a sensitive monitor of the distance from the surface and how the depth profile of evolves with time. The main findings are that the implanted diffuses and traps at the (001) surface. The dependence of the diffusivity is described by a bi-Arrhenius expression with activation energies of 0.3341(21) eV above 200 K, whereas at lower temperatures it has a much smaller barrier of 0.0313(15) eV. We consider possible origins for the surface trapping, as well the nature of the low- barrier.
- Received 4 March 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.095901
© 2019 American Physical Society