Photonic crystals of titanium dioxide fabricated by swift heavy ions

Koichi Awazu*, Makoto Fujimaki, Yoshimichi Ohki, Tetsuro Komatsubara


研究成果: Conference article査読

13 被引用数 (Scopus)


We have developed a method of fabricating nano-micro-structures in a rutile TiO2 single crystal using swift heavy-ion irradiation that takes advantage of the good etching selectivity induced by ion irradiation. The areas into which ions heavier than Cl and accelerated with MeV-order high energy had been irradiated were readily etched by 20% hydrofluoric acid. By comparison, etching was not observed in pristine TiO2 single crystals. We discovered that the irradiated area could be etched to a depth at which the electronic stopping power of the ion decayed to a value of 6.2 keV/nm. In other words, etching was not observed in TiO2 single crystals possessing electron stopping power below a threshold value of 6.2 keV/nm. We also found that the value of the electronic stopping power first increased, and then decreased with depth in TiO2 single crystals when irradiated with, for example, 84.5 MeV Ca ion. Using this type of beam, the inside of the TiO2 single crystal was selectively etched with 20% hydrofluoric acid, while the top surface of the TiO2 single crystal subjected to irradiation was not etched. It initially appeared that an air gap was created in the region 4-8μm from the top surface subjected to irradiation by 84.5 MeV Ca ion at an accumulated dosage of 3×1014cm-2 followed by etching. The roughness of the new surface created in the single crystal was within 7 nm as measured by atomic force microscopy. X-ray diffraction and high-resolution electron microscope analyses indicated that the irradiated area was composed of amorphous and stressed rutile phases. Both phases were highly soluble in 20% hydrofluoric acid.

ジャーナルRadiation Measurements
出版ステータスPublished - 2005 11月
イベントProceedings of the 22nd International Conference on Nuclear Tracks in Soils -
継続期間: 2004 8月 232004 8月 27

ASJC Scopus subject areas

  • 放射線
  • 器械工学


「Photonic crystals of titanium dioxide fabricated by swift heavy ions」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。