2004 Fiscal Year Final Research Report Summary
Study on the three-dimensional structures in silica glass induced by micro- and nano-scale irradiation effects using focused ion beam
| Project/Area Number |
15510112
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Microdevices/Nanodevices
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| Research Institution | Shibaura Institute of Technology |
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Principal Investigator |
NISHIKAWA Hiroyuki Shibaura Institute of Technology, Department of Electrical Engineering, Associate Professor, 工学部, 助教授 (40247226)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Silica glass / microbeam / photoluminescence / Raman scattering / atomic force microscope / refractive index change / optical elements |
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| Research Abstract |
We studied three dimensional structures in silica glass induced by micro- and nano-scale irradiation effects by means of ion microbeam irradiation. Spatial distribution of irradiation effects by ion microbeam on silica glass was investigated by micro-PL/Raman spectroscopy and atomic force microscopy(AFM). High-purity silica glass was irradiated by 1.7-MeV H^+, 15-MeV O^<4+>, or 18-MeV Si^<5+> up to fluences of 1.0×10^<17> ions/cm^2 using microbeam lines at the facility of TIARA(JAERI Takasaki, Japan). The irradiation effects include defect formation, structural changes, and compaction, whose spatial distribution can be mapped out by micro-Raman/PL and AFM. We observed the formation of small ring structures associated with densification and dangling bond defects along with the tracks of ions in silica glass. Surface deformation observed by AFM suggests the internal densification of silica glass by 0.4 %. The H^+ microbeam irradiation shows radiation effects up to depth of 30 μm in the form of refractive index change. On the other hand, the heavy ion irradiations such as O^<4+> and Si^<5+> induce radiation effects limited to the depth of less than 10 μm from the surface with relatively homogeneous distribution. Evaluation of the refractive index change using a microscopic two-beam interferometer shows the change as high as 6×10^<-3> for H^+ microbeam irradiation to the fluence of 1×10^<17> ions/cm^2. We also discuss technological implications of these results on the applications of microbeam irradiation effects to the fabrication of optical elements.
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