Chemical states of implanted ions in an oxide crystal

TLDR: The chemical states of implanted copper and bismuth in an oxide crystal were investigated by using X-ray photoelectron spectroscopy (XPS) in this article, where metal ions were implanted into strontium titanate single crystals with a fluence of 1 × 1016 ions/cm2 at an energy of 150 keV.

Abstract: The chemical states of implanted copper and bismuth in an oxide crystal were investigated by using X-ray photoelectron spectroscopy (XPS). Metal ions were implanted into semiconductive strontium titanate single crystals with a fluence of 1 × 1016 ions/cm2 at an energy of 150 keV. Subsequently oxygen ions were implanted with the appropriate fluences and energies to fit the depth profiles to those of implanted metals. Chemical states of ions were determined by XPS with sputter-etching. The state of implanted Cu which was Cu0 in the as-implanted sample could be changed to Cu1+ by the post-annealing at 800°C in air or by the co-implantation of oxygen. The state of implanted Bi which was Bi0 in the samples as-implanted, post-annealed, and oxygen co-implanted could be changed to Bi3+ by the co-implantation of oxygen followed by heating. Electrical properties were also measured.