| 희토류 첨가 광소재의 나노구조 : Dy 첨가 Ge-As-S 유리의 X-선 흡수 스펙트럼 분석 |
| 최용규, 송재혁1, 신용범2, Vladimir A. Chernov3, 허종1 |
한국항공대학교 항공재료공학과
1포항공과대학교 정보신소재연구소 및 신소재공학과
2한국생명공학연구원 바이오나노연구센터 |
| Nanostructure of Optical Materials Doped with Rare-Earths: X-Ray Absorption Spectroscopy of Dy-Doped Ge-As-S Glass |
| Yong-Gyu Choi, Jay-Hyok Song1, Yong-Beom Shin2, Vladimir A. Chernov3, Jong Heo1 |
Department of Materials Science and Engineering, Hankuk Aviation University
1Center for Information Materials and Department of Materials Science and Engineering, Pohang University of Science and Technology
2Bio-Nanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology
3Siberian Synchrotron Radiation Center, Budker Institute of Nuclear Physics |
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| ABSTRACT |
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Dy $L_3$-edge XANES and EXAFS spectra of chalcogenide Ge-As-S glass doped with ca. 0.2 wt% dysprosium have been investigated along with some reference Dy-containing crystals. Amplitude of the white-line peak in XANES spectrum of the glass sample turns out to be stronger than that of other reference crystals, i.e., $DY_2S_3,;Dy_2O_3;and;DyBr_3$. It has been verified from the Dy $L_3$-edge EXAFS spectra that a central Dy atom is surrounded by $6.7{pm}0.5$ sulfur atoms in its first coordination shell in the Ge-As-S glass, which is relatively smaller than 7.5 of the $Dy_2S_3$ crystal. Averaged Dy-S inter-atomic-distance of the glass ($2.78{pm}0.01{AA}$) also turns out to be somewhat shorter than that of the $Dy_2S_3$ crystal ($2.82{pm}0.01{AA}$). Such nanostructural changes occurring at Dy atoms imply there being stronger covalency of Dy-S chemical bonds in the Ge-As-S glass than in the crystal counterpart. The enhanced covalency in the nanostructural environment of $Dy^{3+}$ ions inside the glass would then be responsible for optical characteristics of the $4f{leftrightarrow}4f$ transitions of the dopants, i.e., increase of oscillator strengths and spontaneous radiative transition probabilities. |
| Key words:
Nanostructure, Dysprosium, Sulfide glasses, Ge-As-S glasses, EXAFS, XANES |
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