Synthesis of cubic and monoclinic hafnia nanoparticles by pulsed plasma in liquid method

Weijian Ma, Tsutomu Mashimo, Makoto Tokuda, Shota Tamura, Shinichi Yoda, Masayuki Tsushida, Hiroshi Isobe, Akira Yoshiasa

Research output: Contribution to journalArticlepeer-review

Abstract

Hafnia (HfO2, hafnium dioxide) is a wide band gap and high-κ material, and the metastable cubic hafnia has a much higher permittivity compared with the normal monoclinic hafnia. Here, we employ a one-step process, the pulsed plasma in liquid (PPL) method to synthesize two types of hafnia nanoparticles (NPs): one which is mainly in cubic phase (cubic: 81.7 at%, monoclinic: 18.3 at%) and the other which is in monoclinic phase. High-resolution transmission electron microscopy images showed that the particles were small (particle size ~3 nm). X-ray absorption fine structure analysis showed no chemical shifts, indicating that the synthetic hafnia NPs contained no oxygen vacancy. The synthetic hafnia NPs mainly in cubic phase showed a much higher relative permittivity than that of the commercial hafnia (monoclinic), and have a larger band gap than the synthetic monoclinic hafnia NPs.

Original languageEnglish
Pages (from-to)33988-33996
Number of pages9
JournalCeramics International
Volume47
Issue number24
DOIs
Publication statusPublished - 2021 Dec 15

Keywords

  • Hafnia
  • Nanoparticles
  • Pulsed plasma in liquid
  • Relative permittivity
  • XAFS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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