• 제목/요약/키워드: Nano Patterns

검색결과 435건 처리시간 0.031초

실리카 템플레이트를 이용하여 다공성 중공형태를 갖는 LiMn2O4 합성 및 전기화학적 특성 연구 (Synthesis and Electrochemical Performance of Mesoporous Hollow Sphere Shape LiMn2O4 using Silica Template)

  • 류성현;류광선
    • 전기화학회지
    • /
    • 제14권3호
    • /
    • pp.184-190
    • /
    • 2011
  • 다공성 중공형태의 $LiMn_2O_4$는 실리카 템플레이트과 침전법에 의해 합성되었다. 합성한 $LiMn_2O_4$는 나노사이즈의 1차입자를 가지며 다공성 중공형태를 가지고 있었다. 실리카 템플레이트의 제거는 NaOH를 이용하여 화학적 에칭법이 사용되었다. NaOH의 농도를 높여줌에 따라 망간산화물 입자 크기가 증가 하며 다공성의 중공구가 형성되었다. X-선 회절 분석을 통하여 합성된 $LiMn_2O_4$는 Fd3m의 공간 그룹을 가지는 스피넬 구조가 형성된 것을 확인 할 수 있었다. 실리카와 망간염의 비율을 높여주었을 경우 합성된 $LiMn_2O_4$는 1차입자의 크기는 감소한다. 실리카와 망간염의 비율이 1 : 9 이상인 경우에서 마이크론 단위의 정방정계의 $LiMn_2O_4$가 합성되었다. 다공성 중공형태의 $LiMn_2O_4$의 전기화학적 특성을 평가하기 위하여 2032형태의 코인셀을 제작하여 충/방전 테스트를 하였다. 나노사이즈의 1차입자를 가진 시료의 경우에는 마이크론 사이즈의 1차입자를 가진 시료보다 용량은 낮았지만 용량유지율은 향상되는 것 확인 할 수 있었다.

BaFe12O19/Ni0.5Zn0.5Fe2O4 나노복합체 Ferrite의 Exchange-coupling 상호 작용과 자기 특성 (Exchange-coupling Interaction and Magnetic Properties of BaFe12O19/Ni0.5Zn0.5Fe2O4 Nanocomposite Ferrite)

  • 오영우
    • 한국자기학회지
    • /
    • 제24권3호
    • /
    • pp.81-85
    • /
    • 2014
  • $BaFe_{12}O_{19}/Ni_{0.5}Zn_{0.5}Fe_2O_4$ 나노복합체 페라이트는 솔-젤 연소법으로 합성하였고, 합성된 나노복합체 페라이트를 $600{\sim}900^{\circ}C$ 범위에서 1시간 동안 하소하였다. XRD 분석 결과, 경자성/연자성 나노복합체에서 경자성과 연자성이 공존하고 있음을 확인하였다. 나노복합체의 입자크기는 90 nm보다 작게 나타났다. 나노복합체는 단일 페라이트의 hysteresis 곡선과 같은 모양을 나타내었으며, 이로서 경자성과 연자성 사이에 exchange coupling이 잘 되었음을 확인할 수 있었다. 경자성/연자성 나노복합체 페라이트의 포화자화 값은 연자성보다 낮고 경자성보다 높았다. 잔류자화 값은 경자성과 연자성보다 크게 나타났고, 전체적으로 $(BH)_{max}$이 향상되었음을 확인할 수 있었다.

우리나라 성인에서 atherogenic index of plasma와 식품군 섭취의 관련성: 도시기반 코호트 자료를 활용하여 (Atherogenic index of plasma and its association with food group intake in Korean adults: based on the baseline data of KoGES-HEXA study)

  • 신혜란;송수진
    • Journal of Nutrition and Health
    • /
    • 제57권1호
    • /
    • pp.105-119
    • /
    • 2024
  • 본 연구는 우리나라 성인 남녀에서 관상동맥질환의 주요 예측 지표인 AIP와 식품군 섭취의 관련성을 분석하였다. 본 연구에서는 40-79세의 성인 남녀 133,381명을 대상으로 AIP 5분위 그룹에 따른 식품군 섭취량을 제시하였으며, 그 결과 AIP가 높은 그룹에서 낮은 그룹에 비해 곡류, 김치/피클류의 섭취가 높았고, 콩류, 종실류, 육류, 난류, 생선류, 우유 및 유제품 등의 섭취가 낮은 경향을 보였다. 본 연구는 한국인의 식사와 관상동맥질환 위험도 간의 관계에 대한 중요한 정보를 제공하며, 관상동맥질환 예방을 위해 다양한 식품군이 포함된 균형 잡힌 식사가 중요함을 시사한다. 본 연구 결과는 관상동맥질환을 예방할 수 있는 식사지침 제시를 위한 기초자료로 활용될 수 있을 것이다. 추후 연구를 통해 한국인의 식사패턴을 분석하여 심혈관질환 발생 및 사망과의 관련성을 조사하고, 이를 통해 한국인의 심혈관질환 예방에 기여할 수 있을 것으로 기대한다.

Data Qualification of Optical Emission Spectroscopy Spectra in Resist/Nitride/Oxide Etch: Coupon vs. Whole Wafer Etching

  • Kang, Dong-Hyun;Pak, Soo-Kyung;Park, George O.;Hong, Sang-Jeen
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
    • /
    • pp.433-433
    • /
    • 2012
  • As the requirement in patterning geometry continuously shrinks down, the termination of etch process at the exact time became crucial for the success in nano patterning technology. By virtue of real-time optical emission spectroscopy (OES), etch end point detection (EPD) technique continuously develops; however, it also faced with difficulty in low open ratio etching, typically in self aligned contact (SAC) and one cylinder contact (OCS), because of very small amount of optical emission from by-product gas species in the bulk plasma glow discharge. In developing etching process, one may observe that coupon test is being performed. It consumes costs and time for preparing the patterned sample wafers every test in priority, so the coupon wafer test instead of the whole patterned wafer is beneficial for testing and developing etch process condition. We also can observe that etch open area is varied with the number of coupons on a dummy wafer. However, this can be a misleading in OES study. If the coupon wafer test are monitored using OES, we can conjecture the endpoint by experienced method, but considering by data, the materials for residual area by being etched open area are needed to consider. In this research, we compare and analysis the OES data for coupon wafer test results for monitoring about the conditions that the areas except the patterns on the coupon wafers for real-time process monitoring. In this research, we compared two cases, first one is etching the coupon wafers attached on the carrier wafer that is covered by the photoresist, and other case is etching the coupon wafers on the chuck. For comparing the emission intensity, we chose the four chemical species (SiF2, N2, CO, CN), and for comparing the etched profile, measured by scanning electron microscope (SEM). In addition, we adopted the Dynamic Time Warping (DTW) algorithm for analyzing the chose OES data patterns, and analysis the covariance and coefficient for statistical method. After the result, coupon wafers are over-etched for without carrier wafer groups, while with carrier wafer groups are under-etched. And the CN emission intensity has significant difference compare with OES raw data. Based on these results, it necessary to reasonable analysis of the OES data to adopt the pre-data processing and algorithms, and the result will influence the reliability for relation of coupon wafer test and whole wafer test.

  • PDF

공침법으로 제조한 Ni-Cu-Zn Ferrite의 Ni 첨가량과 온도에 따른 주파수 및 물리적 특성 연구 (A Study on Frequency and the Physical Properties of Ni-Cu-Zn Ferrites with the Variation of Ni Addition and Temperature Prepared by Co-Precipitation Method)

  • 김문석;고재귀
    • 한국자기학회지
    • /
    • 제15권5호
    • /
    • pp.282-286
    • /
    • 2005
  • 공침법으로 제조한 Ni-Cu-Zn ferrite를 사용하여 전파흡수체로 사용할 저온소결용 ferrite를 연구하였다. Ni 첨가량에 따른 조성비 및 가소온도와 소결온도 변화를 시켜 전파흡수특성 및 물리적 특성을 고찰하였다. XRD pattern을 통하여 spinel구조를 가짐을 확인하였고, 공침법으로 제조된 Ni-Cu-Zn ferrite 미분말이 나노입자 크기를 보였다 소결온도가 $1100^{\circ}C$이고 Ni 함량이 많을 수록 투자율이 낮고 손실계수도 높게 측정되어 흡수 능력도 좋아짐을 알 수 있고, MHz 영역에서 사용할 수 있다고 사료된다. 그리고 소결온도 $1100^{\circ}C$이고 $(Ni_{0.7}Cu_{0.2}Zn_{0.1}O)_{1.02}(Fe_{2}O_3)_{0.98}$ 조성일 때가 가장 손실이 크므로 전파흡수체로 사용할 조성임을 확인 할 수 있었다.

Patterned substrate을 이용하여 MOCVD법으로 성장된 고효율 질화물 반도체의 광특성 및 구조 분석 (Investigation of Structural and Optical Properties of III-Nitride LED grown on Patterned Substrate by MOCVD)

  • 김선운;김제원
    • 한국재료학회지
    • /
    • 제15권10호
    • /
    • pp.626-631
    • /
    • 2005
  • GaN-related compound semiconductors were grown on the corrugated interface substrate using a metalorganic chemical vapor deposition system to increase the optical power of white LEDs. The patterning of substrate for enhancing the extraction efficiency was processed using an inductively coupled plasma reactive ion etching system and the surface morphology of the etched sapphire wafer and that of the non-etched surface were investigated using an atomic force microscope. The structural and optical properties of GaN grown on the corrugated interface substrate were characterized by a high-resolution x-ray diffraction, transmission electron microscopy, atomic force microscope and photoluminescence. The roughness of the etched sapphire wafer was higher than that of the non-etched one. The surface of III-nitride films grown on the hemispherically patterned wafer showed the nano-sized pin-holes that were not grown partially. In this case, the leakage current of the LED chip at the reverse bias was abruptly increased. The reason is that the hemispherically patterned region doesn't have (0001) plane that is favor for GaN growth. The lateral growth of the GaN layer grown on (0001) plane located in between the patterns was enhanced by raising the growth temperature ana lowering the reactor pressure resulting in the smooth surface over the patterned region. The crystal quality of GaN on the patterned substrate was also similar with that of GaN on the conventional substrate and no defect was detected in the interface. The optical power of the LED on the patterned substrate was $14\%$ higher than that on the conventional substrate due to the increased extraction efficiency.

Fabrication of Optically Active Nanostructures for Nanoimprinting

  • Jang, Suk-Jin;Cho, Eun-Byurl;Park, Ji-Yun;Yeo, Jong-Souk
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
    • /
    • pp.393-393
    • /
    • 2012
  • Optically active nanostructures such as subwavelength moth-eye antireflective structures or surface enhanced Raman spectroscopy (SERS) active structures have been demonstrated to provide the effective suppression of unwanted reflections as in subwavelength structure (SWS) or effective enhancement of selective signals as in SERS. While various nanopatterning techniques such as photolithography, electron-beam lithography, wafer level nanoimprinting lithography, and interference lithography can be employed to fabricate these nanostructures, roll-to-roll (R2R) nanoimprinting is gaining interests due to its low cost, continuous, and scalable process. R2R nanoimprinting requires a master to produce a stamp that can be wrapped around a quartz roller for repeated nanoimprinting process. Among many possibilities, two different types of mask can be employed to fabricate optically active nanostructures. One is self-assembled Au nanoparticles on Si substrate by depositing Au film with sputtering followed by annealing process. The other is monolayer silica particles dissolved in ethanol spread on the wafer by spin-coating method. The process is optimized by considering the density of Au and silica nano particles, depth and shape of the patterns. The depth of the pattern can be controlled with dry etch process using reactive ion etching (RIE) with the mixture of SF6 and CHF3. The resultant nanostructures are characterized for their reflectance using UV-Vis-NIR spectrophotometer (Agilent technology, Cary 5000) and for surface morphology using scanning electron microscope (SEM, JEOL JSM-7100F). Once optimized, these optically active nanostructures can be used to replicate with roll-to-roll process or soft lithography for various applications including displays, solar cells, and biosensors.

  • PDF

Photovoltaic Efficiencies on Dye-Sensitized Solar Cells Assembled with Graphene-Linked TiO2 Anode Films

  • Kim, A-Young;Kim, Ji-Eun;Kim, Min-Young;Ha, Seung-Won;Tien, Ngyen Thi Thuy;Kang, Mi-Sook
    • Bulletin of the Korean Chemical Society
    • /
    • 제33권10호
    • /
    • pp.3355-3360
    • /
    • 2012
  • To promote the photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs), graphene is introduced as a working electrode with $TiO_2$ in this study, because it has great transparency and very good conductivity. XRD patterns indicate the presence of graphene and $TiO_2$ particles in graphene-linked $TiO_2$ samples. Moreover, TEM pictures also show that the nano-sized $TiO_2$ particles are highly dispersed and well-linked onto the thin layered graphene. On the basis of the UV-visible spectra, the band gaps of $TiO_2$, 1.0 wt % graphene-$TiO_2$, 5.0 wt % graphene-$TiO_2$, and 10.0 wt % graphene-$TiO_2$ are 3.16, 2.94, 2.25, and 2.11 eV, respectively. Compared to pure $TiO_2$, the energy conversion efficiency was enhanced considerably by the application of graphene-linked $TiO_2$ anode films in the DSSCs to approximately 6.05% for 0.1 wt % graphene-$TiO_2$ with N719 dye (10.0 mm film thickness and $5.0mm{\times}5.0mm$ cell area) under $100mW/cm^2$ of simulated sunlight. The quantum efficiency was the highest when 1.0 wt % of graphene was used. In impedance curves, the resistance was smallest for 1.0 wt % graphene-$TiO_2$-DSSC.

유기변성 LDH를 사용한 난연 ABS 나노복합재료의 열적 및 기계적 물성 (Thermal and Mechanical Properties of Flame Retardant ABS Nanocomposites Containing Organo-Modified Layered Double Hydoxide)

  • 김석준
    • Elastomers and Composites
    • /
    • 제43권4호
    • /
    • pp.241-252
    • /
    • 2008
  • 올레인산으로 유기변성된 ZnAl-LDH(SO-ZnAl LDH)를 합성하여 브롬화 에폭시 수지(BER) 및 산화안티몬을 포함하는 난연 ABS 컴파운드에 첨가하였다. 난연 ABS 컴파운드는 동일방향으로 회전하는 이축압출기를 통해 제조되었고 난연성 및 기계적 성질을 측정하기 위한 시편으로 사출성형 되었다. ABS 나노복합재료의 XRD 패턴에서는 피크가 나타나지 않았다. SOZnAl LDH를 포함하는 난연 ABS 나노복합재료는 TGA 시험 결과 향상된 내열성을 보였다. 그러나, 난연 ABS 나노복합재료들은 UL 94 수직시험(1.6 mm 두께)시 등급을 얻지 못했다. BER를 1.5 wt% 이상 더 첨가한 경우들에서만 UL 94 V0 등급을 얻을 수 있었다. SO-ZnAl LDH의 첨가량에 비례하여 난연 ABS 나노복합재료의 노치드 아이조드 충격강도, 인장탄성률 및 신율은 증가하였으나 유동지수는 감소하였다.

증착온도를 달리하여 제조한 Zn0.8Co0.2O 박막의 미세조직 및 자기 특성 (Microstructure and Magnetic Properties of Pulsed DC Magnetron Sputtered Zn0.8Co0.2O Film Deposited at Various Substrate Temperatures)

  • 강영훈;김봉석;태원필;김기출;서수정;박태석;김용성
    • 한국세라믹학회지
    • /
    • 제43권2호
    • /
    • pp.79-84
    • /
    • 2006
  • We studied the microstructure and magnetic property of the pulsed DC magnetron sputtered $Zn_{\0.8}Co_{0.2}O$ film as a function of substrate temperatures. The X-ray patterns of the $Zn_{\0.8}Co_{0.2}O$ film showed a strong (002) preferential orientation at $500^{\circ}C$. The films with a crystallite size of 23-35 nm were grown in the form of nano-sized structure and this tendency was remarkable with increasing substrate temperature. The UV-visible result showed that the $Zn_{\0.8}Co_{0.2}O$ film prepared above $300^{\circ}C$ has a high optical transmittance of over $80\%$ in the visible region. The absorption bands were observed due to sp-d interchange action by $Co^{2+}$ complex ion and dd transition in the region from 500 to 700nm. The resistivity of the film was below $10^{-1}\;\Omega-cm\;above\;300^{\circ}C$. The AGM analysis results for the all films showed the magnetic hysteresis curves of ferromagnetic nature. The low electrical resistivity and room temperature ferromagnetism of ZnCoO thin films 'deposited above $300^{\circ}C$ suggested the possibility for the application to Diluted Magnetic Semiconductors (DMSs).