반도체 조명 및 AVR 디스플레이 광원 적용을 위한 나노 구조 및 공정 개발

김제원 한국조명.전기설비학회 2018 조명·전기설비학회논문지 Vol.32 No.12

The purpose of this study is to produce the three-dimensional structure with the application of nano-mold process. The three-dimensional structure and growth will be more appropriately provided through nano manufacturing process using mask patterning and etching process. This study will show multiple wavelength of light emitting diodes different from the single wavelength of existing ones through formation of nano-mold with uniformity and reproducibility. This study will show the characteristics of various wavelengths beyond blue and green through newly developed nano-mold and its nanorod array. This research will also prove the feasibility of the white light emitting diode without phosphor as multiple wavelength in a single chip can be realized. This kind of study about the light emitting diode with nano structure is actively being conducted to develop the next generation technology for semiconductor lighting, AVR and wearable displays. This study is aimed at forming new nano-mold applied with semiconductor's manufacturing process, suggesting the new characteristics of nano structure by the way of realizing the light emitting diode of three-dimensional structure by this mold.

세차전자회절을 이용한 $BaTiO_3$ 나노 결정의 구조분석

송경,김윤중,권기현,김진규,문선민,조남희,Song, Kyung,Kim, Youn-Joong,Kwon, Ki-Hyun,Kim, Jin-Gyu,Moon, Sun-Min,Cho, Nam-Hee 한국현미경학회 2009 Applied microscopy Vol.39 No.4

본 연구에서는 평균 입자크기가 100 nm인 $BaTiO_3$ 나노 결정체의 결정 구조를 전자회절을 이용하여 분석하였다. 전자회절을 이용하여 구조분석을 수행하기 위해 PED 장치의 실험인자를 보정한 후, PED와 일반적인 SAED를 이용하여 전자회절도형을 획득하여 비교 분석을 수행하였다. $BaTiO_3$ 나노 결정체에 대해 PED를 이용한 구조분석을 수행한 결과, $BaTiO_3$ 나노입자는 상온에서 입방정계와 정방정계의 구조가 혼합되어 존재함을 알 수 있었다. 또한 이론적 계산을 통해 두 상이 혼재된 $BaTiO_3$ 나노입자는 입방정계의 구조가 약 8.5nm의 표면을 형성하고 있는 coreshell 구조를 이루고 있음을 예측할 수 있었다. 이러한 $BaTiO_3$ 나노입자에 대한 입방정계와 정방정계 구조의 각각의 격자상수는 a=3.999${\AA}$과 a=3.999${\AA}$, c=4.022${\AA}$이었다. 이와 같이 일반적인 SAED에 비해 뛰어난 공간분해능과 다중산란 효과를 억제할 수 있는 PED 기법은 복합 나노 구조체의 결정구조분석에 보다 유용한 분석 기술로 활용할 수 있을 것으로 기대된다. The crystal structure of nano-crystalline, $BaTiO_3$, with the average particle size of 100 nm was investigated using electron diffraction techniques. We characterized the precession electron diffraction system and then carried out the structure determination using precession electron diffraction and conventional selected area electron diffraction. As a result, it was revealed that $BaTiO_3$ nano-crystalline exist as a mixture of tetragonal structure and cubic structure by precession electron diffraction technique. In addition, it could be turned out that $BaTiO_3$ nano-crystalline is a core-shell structure consisted of a tetragonal phased core and a cubic phased surface layer by theoretical calculation. The thickness of the cubic surface layer was approximately 8.5 nm and the lattice parameters of cubic and tetragonal phases were a=3.999${\AA}$ and a=3.999${\AA}$, c=4.022${\AA}$, respectively. Finally, it is expected that precession electron diffraction is more useful technique for structure determination of complicated nano-crystalline materials because of its higher spatial resolution and minimization of dynamical scattering effect.

자연모사기반 나노-마이크로패턴의 광 회절 및 간섭에 의한 투명기판의 구조색 구현

박용민(Yong Min Park),김병희(Byeong Hee Kim),서영호(Young Ho Seo) 강원대학교 산업기술연구소 2019 産業技術硏究 Vol.39 No.1

This paper addresses effects of nanoscale structures on structural colors of micropatterned transparent substrate by light diffraction. Structural colors is widely investigated because they present colors without any chemical pigments. Typically structural colors is presented by diffraction of light on a micropatterned surface or by multiple interference of light on a surface containing a periodic or quasi-periodic nano-structures. In this paper, each structural colors induced by quasi-periodic nano-structures, periodic micro-structures, and nano/micro dual structures is measured in order to investigate effects of nanoscale and microscale structures on structural colors in the transparent substrate. Using pre-fabricated pattern mold and hot-embossing process, nanoscale and microscale structures are replicated on the transparent PMMA(Poly methyl methacrylate) substrate. Nanoscale and microscale pattern molds are prepared by anodic oxidation process of aluminum sheet and by reactive ion etching process of silicon wafer, respectively. Structural colors are captured by digital camera, and their optical transmittance spectrum are measured by UV/visible spectrometer. From experimental results, we found that nano-structures provide monotonic colors by multiple interference, and micro-structures induce iridescent colors by diffraction of light. Structural colors is permanent and unchangeable, thus it can be used in various application field such as security, color filter and so on.

나노인덴터를 이용한 박막 구조의 잔류응력 평가 방법

김재현(Jae Hyun Kim),이학주(Hak Joo Lee),김정엽(Jung Yup Kim),최병익(Byung Ik Choi) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.8

Residual stress of thin film structure is closely related to the reliability of micro/nano devices. This causes delamination, fracture and buckling of thin film structure and eventually leads to failure of the device containing the thin film. In this study, some useful relationships are derived based on solid mechanics concept with a focus of residual stress estimation and an analysis procedure is proposed to determine the residual stress of thin film structure. A scheme for measuring residual stress of thin film structure is presented by combining the proposed analysis procedure with nano indenter test. The nano indenter is used as a nano/micro mechanical test machine with high displacement and load resolution to determine the load-displacement behavior of the membrane structure. The feasibility of the measurement scheme is studied by simulating the behavior of gold membrane.

탄소나노튜브 스마트 복합소재를 이용한 인공뉴런 개발 연구

강인필(Inpil Kang),백운경(Woonkyung Baek),최경락(Gyeong Rak Choi),정주영(Joo Young Jung) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

This paper introduces an artificial neuron which is a nano composite continuous sensor. The continuous nano sensor is fabricated as a thin and narrow polymer film sensor that is made of carbon nanotubes composites with a PMMA or a silicone matrix. The sensor can be embedded onto a structure like a neuron in a human body and it can detect deteriorations of the structure. The electrochemical impedance and dynamic strain response of the neuron change due to deterioration of the structure where the sensor is located. A network of the long nano sensor can form a structural neural system to provide large area coverage and an assurance of the operational health of a structure without the need for actuators and complex wave propagation analyses that are used with other methods. The artificial neuron is expected to effectively detect damage in large complex structures including composite helicopter blades and composite aircraft and vehicles.

나노구조기판의 형상 및 온도변화에 따른 액체 클러스터의 거동에 대한 분자동역학적 연구

고선미 ( Sun Mi Ko ),정흥철 ( Heung Cheol Jeong ),최경민 ( Gyung Min Choi ),김덕줄 ( Duck Jool Kim ),( Masahiko Shibahara ) 한국액체미립화학회 2008 한국액체미립화학회지 Vol.13 No.1

Molecular dynamic simulations have been carried out to study the effect of the nano-structure substrate and its temperature on cluster laminating. The interaction between substrate molecules and liquid molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand behaviors of the liquid cluster on nano-structure substrate. In the present model, the Lennard-Jones potential is applied to mono-atomic molecules of argon as liquid and platinum as nano-structure substrate to perform simulations of molecular dynamics. The effect of wettability on a substrate was investigated for the various beta of Lennard-Jones potential. The behavior of the liquid cluster and nano-structure substrate depends on interface wettability and function of molecules force, such as attraction and repulsion, in the collision progress. Furthermore, nano-structure substrate temperature and beta of Lennard-Jones potential have effect on the accumulation ratio. These results of simulation will be the foundation of coating application technology for micro fabrication manufacturing.

나노 허니콤 구조물의 계층화를 통한 강성 변화 예측

이용희(Yonghee Lee),조맹효(Maenghyo Cho) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

The mechanical properties and characteristics of the nano-sized hierarchical cellular structure with the surface effect are studied. The surface effect is dominant in the nano scale, which influences greatly the mechanical behavior of cellular structures. Atomistic simulations such as molecular statics and dynamics can predict the mechanical behavior of nano structures. However, these simulations require a large amount of calculation time and computing resources. Therefore, an efficient method is required to predict effectively and accurately this honeycomb cellular structures.Thus, the continuum-based bridging method is developed for the analysis of mechanical behavior of the nano-sized structures. Hierarchy of the structure is useful for the higher stiffness in the cellular structures. In this paper, for reinforcing the nano-sized structure without a loss of the high surface-area to volume ratio, the hierarchy of honeycomb structure is used. The mechanical characteristics are investigated in sup-cell and sub-cell hierarchical honeycomb configurations.

나노 구조체를 이용한 산화질소 전달체에 대한 연구 및 바이오메디컬 응용

최윤서,정혜중,박경태,홍진기 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.3

The discovery of nitric oxide (NO) as a major signaling molecule in a number of pathophysiological processes – vasodilation, immune response, platelet aggregation, wound repair, and cancer biology – has led to the development of various exogeneous NO delivery systems. However, the development of ideal delivery system for human body application is still left as a challenge due to its high reactivity and short half-life in physiological condition. In this article, an overview of several nano-structures as potential NO delivery system will be presented, along with their recent research results and biomedical applications. Nano-size delivery system has immense advantages compared to others due to its high surface-to-volume ratio and capability for surface modification; thus, it has been proven to be effective in delivering nitric oxide with enhanced performance. Through this novel nano-structure delivery system, we are expecting to achieve sustained release of nitric oxide within adequate range of concentration, which ensures desired drug effects at the target site. Among different nano-structures, in particular, nanoparticle, microemulsion and nanofilm will be reviewed and compared to each other in respect of nitric oxide release profile. The proposed nano-structures for exogeneous NO delivery have a biological significance in that it can be further utilized in diverse biomedical fields as a highly promising therapeutic method. 산화질소(NO)가 혈관 확장, 혈소판 응집 억제, 면역 반응 조절, 상처 치료, 항암 등의 주요 병리 생리학적 프로세스에 관여한다는 사실이 밝혀지면서 최근 산화질소 전달에 대한 국내외 연구진들의 관심이 높아지고 있다. 그러나 인체에 이상적으로 적용될 수 있는 산화질소 전달체의 개발은 산화질소의 높은 반응성과 짧은 반감기로 인하여 여전히 난제로 남아 있다. 본 논문에서는 다양한 산화질소 전달체 중에서도 최근 바이오메디컬 분야에서 연구가 활발히 이루어지고 있는 나노 구조체를 이용한 전달체의 연구 결과 및 응용 방향에 대해서 소개하고자 한다. 나노 크기의 구조체가다른 전달체와 비교하여 가지는 장점은 표면 대 부피 비율이 높아 산화질소를 효율적으로 탑재할 수 있고, 표면 개조능력이 뛰어나 산화질소의 방출 양상을 효과적으로 제어할 수 있다는 것이다. 특히 이 글에서는 다양한 나노 구조체중에서도 나노입자 형태, 마이크로에멀젼 형태, 그리고 다층필름 형태의 나노 구조체에 대해서 다룸으로써 각 구조체의 산화질소 방출 양상을 비교하고 그 특징에 대해서 자세히 알아보고자 한다. 이와 같은 나노 구조체의 개발은 산화질소의 급격한 방출을 방지하고 지효성을 띠게 함으로써 타겟 부위에서의 효과를 높일 수 있을 것으로 기대되며, 더나아가 차후 다양한 바이오메디컬 분야에서 유망한 치료 기제로서 적용될 수 있을 것으로 보인다.

Pseudocapacitive Properties of Nano-structured Anhydrous Ruthenium Oxide Thin Film Prepared by Electrostatic Spray Deposition and Electrochemical Lithiation/Delithiation

Park, S.-H.,Kim, J.-Y.,Kim, K.-B. WILEY-VCH Verlag 2010 FUEL CELLS -WEINHEIM- Vol.10 No.5

<P>Nano-structured anhydrous ruthenium oxide (RuO(2)) thin films were prepared using an electrostatic spray deposition (ESD) technique followed by electrochemical lithiation and delithiation. During the electrochemical lithiation process, RuO(2) decomposed to nano-structured metallic ruthenium Ru with the concomitant formation of Li(2)O. Nano-structured RuO(2) was formed upon subsequent electrochemical extraction of Li from the Ru/Li(2)O nanocomposite. Electrochemical lithiation/deliathiation at different charge/discharge rates (C-rate) was used to control the nano-structure of the anhydrous RuO(2). Electrochemical lithiation/delithiation of the RuO(2) thin film electrode at different C-rates was closely related to the specific capacitance and high rate capability of the nano-structured anhydrous RuO(2) thin film. Nano-structured RuO(2) thin films prepared by electrochemical lithiation and delithiation at 2C rate showed the highest specific capacitance of 653 F g(-1) at 20 mV s(-1), which is more than two times higher than the specific capacitance of 269 F g(-1) for the as-prepared RuO(2). In addition, it showed 14% loss in specific capacitance from 653 F g(-1) at 20 mV s(-1) to 559 F g(-1) at 200 mV s(-1), indicating significant improvement in the high rate capability compared to the 26% loss of specific capacitance of the as-prepared RuO(2) electrode from 269 F g(-1) at 20 mV s(-1) to 198 F g(-1) at 200 mV s(-1) for the same change in scan rate.</P>

나노 허니콤 구조물의 계층화에 따른 기계적 물성의 변화

이용희,정준호,조맹효 한국항공우주학회 2011 한국항공우주학회 학술발표회 논문집 Vol.2011 No.11

나노 허니콤 구조물은 표면효과에 의해 거시적 크기의 허니콤 구조물과 다른 기계적 거동을 보이고 있다. 본 연구에서는 표면 응력 탄성 모델을 적용한 브릿징 방법을 이용하여 표면효과를 고려한 나노 허니콤 구조물의 기계적 거동을 예측하였다. 이 과정에서 보다 효율적인 계산을 위해 균질화 기법과 차원 축소법을 접목하였다. 나노 허니콤 구조물에서의 계층적 구조는 부피 대비 높은 표면적을 유지하며 높은 강성을 획득할 수 있는 방법이 될 수 있으며, 본 연구에서는 나노 허니콤 구조물에서의 계층화에 따른 기계적 물성 변화를 예측하였다. The nano-sized honeycomb structure exhibits the different mechanical behavior from ones of the macro-sized honeycomb structure due to the surface effects. In this study, the mechanical behavior of the nano-sized honeycomb considering the surface effects is estimated by using the bridging method combined with the surface elasticity stress model. In this process, for the purpose of computational efficiency, the homogenization method and dimensional reduction method is applied. The hierarchy of the nano-sized honeycomb structure can be a way to get the high stiffness without the loss of the high ratio of the surface-to-volume. In this study, a change of the mechanical properties of the nano-sized honeycomb structure due to hierarchy is predicted.