Vanadium oxide precipitates in sapphire formed by ion implantation

Hiroaki Abe, Hiroshi Naramoto, Shunya Yamamoto

Research output: Contribution to journalConference articlepeer-review


Some vanadium oxides undergo phase transformations which give rise to attributable for large variations in optical and electronic properties. Since one can expect dynamic rearrangement of implanted species and a distorted lattice due to implantation, we investigated the precipitation process under ion implantation at high temperature. Sapphire samples were implanted with 300-keV V+ ions at temperatures from 470 to 1070 K in a transmission electron microscope interfaced with ion accelerators. Evolution of vanadium oxide precipitates was observed simultaneously. Damage evolution such as dislocation loops and voids were observed at fluences of the order of 1018-1019 and 1020 ions/m2, respectively. At implantation fluence of the order of 1021 ions/m2, dot and plate contrast was observed in addition to radiation damage. Electron diffraction analysis reveals that hexagonal and monoclinic V2O3, tetragonal and monoclinic VO2, and V7O13 precipitates were formed in the substrate depending on the surface normal of the substrate. Some of precipitates were thermally unstable phases. Crystallographic relationship between matrix and the precipitates was investigated as well as the swelling effect both in the substrate and in the precipitates. Temperature dependence reveals precipitation starts at temperature higher than 670 K.

Original languageEnglish
Pages (from-to)393-398
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Publication statusPublished - 1999 Jan 1
EventProceedings of the 1997 MRS Fall Symposium - Boston, MA, USA
Duration: 1997 Nov 301997 Dec 4

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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