• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1599-1602
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• 2002

$Zn_4SnSe_6$ and $Zn_4SnSe_6:Co^{2+}$ single crystals were by the chemical transport reaction method. They crystallized in the monoclinic structure. The direct energy band gaps of the $Zn_4SnSe_6$ and $Zn_4SnSe_6:Co^{2+}$ single crystals at 289K were found to be 2.146eV and 2.042eV. Optical absorption due to impurity in the $Zn_4SnSe_6:Co^{2+}$ single crystal was observed and described as originating from the electron transition between energy leveles of $Co^{2+}$ sited at $T_d$ symmetry point.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권1호
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• pp.1-5
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• 2003

Zn$_4$SnSe$_{6}$ and Zn$_4$SnSe$_{6}$ :Co$^{2+}$ single crystals were by the chemical transport reaction method. They crystallized in the monoclinic structure. The direct energy band gaps of the Zn$_4$SnSe$_{6}$ and Zn$_4$SnSe$_{6}$ :Co$^{2+}$single crystals at 289k were found to be 2.146eV and 2.042eV. Optical absorption due to impurity in the Zn$_4$SnSe$_{6}$ :Co$^{2+}$single crystal was observed and described as originating from the electron transition between energy levels of Co$^{2+}$ion sited at T$_{d}$ symmetry point.y point.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.88-93
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• 2002

$Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$ and $Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}:Co^{2+}$ + single crystals were grown by CTR method. The grown single crystals have defect chalcopyrite structure with lattice constant a= 5.5966A. c= 10.8042${{\AA}}$ for the pure. a= 5.6543${{\AA}}$. c= 10.8205${{\AA}}$ for the Co-doped single crystal. respectively. The optical energy band gap was given as indirect band gap. The optical energy band gap was decreased according to add of Co-impurity. Temperature dependence of optical energy band gap was fitted well to the Varshni equation. From this relation. we can deduced the entropy. enthalpy and heat capacity. Also. we can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• 한국결정성장학회지
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• 제11권5호
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• pp.203-206
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• 2001

The applicability of shaped growth of yttrium orthovanadate was approved by successful growth of rod-like single crystals with the rectangular shape. Nd-doped single crystals with content of $Nd^{3+}$ ions of 1,2,3,5 atomic % in the starting melt were grown by the EFG technique with the size up to $10^{*}10mm$ in section and up to 85 mm in length. For the testing of the multiple growth of the orthovanadates, two and three Nd-and Yb-doped $YVO_{4}$ single crystals were grown by the EFG technique simultaneously up to 110 mm in length.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.31-36
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• 2002

In this work $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}:Co^{2+}$ single crystals were grown by the chemical transport reaction method and the structure of $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}:Co$ single crystals were monoclinic structure. The temperature dependence of optical energy gap was fitted well to Varshni equation. Also, the entropy, enthalpy and heat capacity were deduced from the temperature dependence of optical energy gap.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.594-597
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• 2008

This presentation introduces a simple strategy for producing 2D photonic crystal layers (PCL) with different structures. In an attempt to improve extraction efficiency from the thin film phosphors (TFPs), this study have examined the effects of the structural variables of the 2D PCLs on the light extraction efficiency of TFPs.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.228-229
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• 2003

광자 크리스탈의 밴드 구조가 다른 물질이 접하는 경계면으로 구성되는 이종 접합 구조(Heteorostructure)는 단일 구조에서 관찰할 수 없는 특성을 보유하고 있으므로 관심을 끌고 있다. 이를 이용한 다 파장 add-drop 필터, 2D-3D 하이브리드 구조에 의한 무 회절 손실 도파로, beam splitter와 combiner 등의 연구 결과가 최근에 제시되었다. 본 논문에서는 positive 굴절율과 negative 굴절율을 갖는 광자 크리스탈이 이종 접합 구조를 형성할 때의 굴절 작용의 변화를 실린더의 반지름 변화에 따라 고찰하였다. (중략)

• Current Optics and Photonics
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• 제7권6호
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• pp.638-654
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• 2023

Holography is generally known as a technology that records and reconstructs 3D images by simultaneously capturing the intensity and phase information of light. Two or more interfering beams and illumination of this interference pattern onto a photosensitive recording medium allow us to control both the intensity and phase of light. Holography has found widespread applications not only in 3D imaging but also in manufacturing. In fact, it has been commonly used in semiconductor manufacturing, where interference light patterns are applied to photolithography, effectively reducing the half-pitch and period of line patterns, and enhancing the resolution of lithography. Moreover, holography can be used for the manufacturing of 3D regular structures (3D photonic crystals), not just surface patterns such as 1D or 2D gratings, and this can be broadly divided into (i) holographic recording and (ii) holographic lithography. In this review, we conceptually contrast two seemingly similar but fundamentally different manufacturing methods: holographic recording and holographic lithography. We comprehensively describe the differences in the manufacturing processes and the resulting structural features, as well as elucidate the distinctions in the diffractive optical properties that can be derived from them. Lastly, we aim to summarize the unique perspectives through which each method can appear distinct, with the intention of sharing information about this field with both experts and non-experts alike.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.245-249
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• 2010

Two dimensional(2D) pair-photonic crystals (pair-PCs) have been fabricated by a multiple-exposure nanosphere lithography (MENSL) method using the self-assembled nanospheres as lens-mask patterns and the collimated laser beam as a multiple-exposing source. The arrays of the 2D pair-PCs exhibited variable lattice structures and shape the control of rotating angle (${\Theta}$), tilting angle (${\gamma}$) and the exposure conditions. In addition, the base period or filling factor of pair-PCs as well as their shapes could be changed by experimental conditions and nanosphere size. A 1.18-${\mu}m$-thick resist was spincoated on Si substrate and the multiple exposure was carried out at change of ${\gamma}$ and ${\Theta}$. Images of prepared 2D pair-PCs were observed by SEM. We believe that the MENSL method is a suitable useful tool to realize the pair-periodic arrays of large area.

• 대한화학회지
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• 제21권5호
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• pp.339-352
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• 1977

소성변형에 대한 저자들의 이론(제1보)을 요업재료, 금속, 합금 및 단결정들에 적용하였다. 그 결과 다중 결정에서는 dislocation 운동과 grain boundary 운동이 실험조건에 따라 함께 또는 분리되어 나타나는 반면 단결정에서는 dislocation 운동만 나타났다. 유동식에 나타나는 파라미터$({\alpha}_{d1},\;1/{\beta}_{d1})와\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2) 및 활성화엔탈피 ${\Delta}H_{k1}^{\neq}$ (k = d 혹은 g)를 구하여 예측한 소성변형은 실험과 잘 일치함을 보았다. 여기서 첨자 d1는 첫번째의 dislocation 유동단위, gj는 j번째 grain boundary 유동단위를 나타낸다. 활성화엔탈피에 대하여 ${\Delta}H_{d1}^{\neq}$는 bulk의 자체확산에 대한 활성화엔탈피와 일치하고 ${\Delta}H_{g1}^{\neq}$는 grain boundary 자체확산에 대한 활성화엔탈피와 일치하였다. 이 사실은 저자들의 이론의 정당성을 보이고 있다.