• 센서학회지
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• 제30권2호
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• pp.71-75
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• 2021

Recently, transition-metal-based hydroxide materials have attracted significant attention in various electrochemical applications owing to their low cost, high stability, and versatility in composition and morphology. Among these applications, transition-metal-based hydroxides have exhibited significant potential in supercapacitors owing to their multiple redox states that can considerably enhance the supercapacitance performance. In this study, nanostructured Ni-Mn double hydroxide is directly grown on a conductive substrate using an electrodeposition method. Ni-Mn double hydroxide exhibits excellent electrochemical charge-storage properties in a 1 M KOH electrolyte, such as a specific capacitance of 1364 Fg-1 at a current density of 1 mAcm-2 and a capacitance retention of 94% over 3000 charge-discharge cycles at a current density of 10 mAcm-2. The present work demonstrates a scalable, time-saving, and cost-effective approach for the preparation of Ni-Mn double hydroxide with potential application in high-charge-storage kinetics, which can also be extended for other transition-metal-based double hydroxides.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.76-76
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• 2011

Polymer-fullerene based bulk heterojunction (BHJ) solar cells can be fabricated in large area using low-cost roll-to-roll manufacturing methods. However, because of the low mobility of the BHJ materials, there is competition between the sweep-out of the photogenerated carriers by the built-in potential and recombination within the thin BHJ film [12-15]. Useful film thicknesses are limited by recombination. Thus, there is a need to increase the absorption by the BHJ film without increasing film thickness. Metal nanoparticles exhibit localized surface plasmon resonances (LSPR) which couple strongly to the incident light. In addition, relatively large metallic nanoparticles can reflect and scatter the light and thereby increase the optical path length within the BHJ film. Thus, the addition of metal nanoparticles into BHJ films offers the possibility of enhanced absorption and correspondingly enhanced photo-generation of mobile carriers. In this work, we have demonstrated several positive effects of shape controlled Au and Ag nanoparticles in organic P3HT/PC70BM, PCDTBT/PC70BM, Si-PCPDTBT/PC70BM BHJ-based PV devices. The use of an optimized concentration of Au and Ag nanomaterials in the BHJ film increases Jsc, FF, and the IPCE. These improvements result from a combination of enhanced light absorption caused by the light scattering of the nanomaterials in an active layer. Some of the metals induce the plasmon light concentration at specific wavelength. Moreover, improved charge transport results in low series resistance.

• 대한전자공학회논문지SD
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• 제43권8호
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• pp.13-18
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• 2006

Sn과 Zn 금속을 이용해 각각 산소와 아르곤 가스를 주입한 대기압 분위기에서 열처리를 통해 $SnO_2$와 ZnO 나노박막을 형성시켰다. 나노구조로 형성된 $SnO_2$ 박막의 경우 CO 가스(5,000 ppm)에 대해 $200^{\circ}C$의 동작온도에서 약 50 %의 감도를 나타내었으며, $SnO_2$ 나노 금속산화물에 Pt 금속을 이온 코팅법에 의해 첨가한 박막의 경우에는 동작온도 $150^{\circ}C$에서 73 %의 높은 감도를 얻을 수 있었다. 순수 ZnO 나노 박막의 경우 NOx(20 ppm) 가스에 대해 낮은 감도를 나타내었으나, Cu를 이온 코팅법에 의해 첨가한 박막의 경우에는 동작온도 $200^{\circ}C$에서 90 %의 높은 감도를 나타내었다. 나노 구조가 아닌 $SnO_2$와 ZnO 박막이 가지는 CO와 NOx에 대한 가스 감도에 비해 매우 높은 감도를 가짐을 알 수 있었다.

• 한국결정성장학회지
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• 제16권6호
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• pp.256-259
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• 2006

Vapor phase epitaxy(VPE)법을 사용하여 amorphous $SiO_x$. nanowires를 성장시켰다. Ni thin film을 촉매로 사용하여 Si 기판위에 $800{\sim}1100^{\circ}C$ 범위의 온도에서 성장시켰으며, $SiO_x$ nanowires의 성장 메커니즘은 Vapor-liquid-solid(VLS)으로 확인되었다. $SiO_x$ nanowires의 shape와 morphology는 scanning electron microscope(SEM)으로 분석하였으며, cotton-like형태이고 길이는 $10{\mu}m$정도였다. 그리고 구조적 특징은 transmission electron microscope(TEM)으로 관찰하였고, $SiO_x$ nanowires의 성분 분석은 energy dispersed X-ray spectroscopy(EDS)로 하였다. EDX spectrum으로 nanowires가 Si와 O로 구성되어졌음을 확인하였다.

• 전기화학회지
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• 제2권4호
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• pp.237-241
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• 1999

펄스전착법에 의한 구리박막의 특성과 via hole 충진 특성을 연구하였다. 특히 구리박막의 특성에 미치는 첨가제의 영향을 중점적으로 다루었다. 펄스 전류와 첨가제를 사용하여 전착한 구리박막은 83.4 MPa이하의 낮은 인장응력을 가졌으며 높은 Cu (111) 우선 배향성을 나타냈다. Superfilling에 의해 최고 $0.25{\mu}m, 6: 1$ 정도의 고 종횡비를 가지는 via hole에 결함 없이 성공적으로 충진할 수 있었으며 미세 구조를 관찰한 결과 쌍정에 의한 변형이 일어났음을 알 수 있었다. $500^{\circ}C$에서 1시간 동안 진공열처리를 했을 경우 두께의 $1\~2$배에 달하는 결정립을 가지는 bamboo구조를 나타냈으며 이때 전기비저항은 $1.8\~2.0{\mu}{\Omega}{\cdot}cm$을 나타냈다.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.1-6
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• 2008

블록공중합체(block copolymer)는 각 고분자 블록의 상대적인 조성비와 분자량에 따라 구, 실린더, 라멜라 등의 다양한 자기조립 나노구조를 형성하는 것으로 알려져 있다. 최근에는 블록공중합체의 자기조립 나노구조를 이용하여 나노복합재료, 포토닉 크리스탈, 나노선, 자기저장매체, 플래시 메모리 소자 등에 적용하려는 연구들이 활발히 진행되고 있다. 그러나 자연적으로 형성되는 블록공중합체 나노구조는 수많은 결함구조들을 포함하고 있어 실제 소자 적용에 큰 걸림돌이 되고 있다. 블록공중합체 나노구조의 실제적인 응용을 위해서는 박막상태의 시료 내에서 나노구조의 배향과 배열을 원하는 형태로 조절할 수 있는 공정의 확립이 선행되어야 한다. 즉, 블록공중합체의 자기조립을 나노기술분야에 적용하기 위해서는 대면적으로 완벽히 제어된 블록공중합체 나노구조를 구현하는 것이 필요하다.

• 센서학회지
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• 제23권5호
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• pp.291-294
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• 2014

In this study, a chemiresistive sensor based on one-dimensional $WO_3$ nanostructures is presented for application in non-invasive medical diagnostics. $WO_3$ nanostructures were used as an active gas sensing layer and were deposited onto a $SiO_2/Si$substrate using Pt interdigitated electrodes (IDEs). The IDE spacing was $5{\mu}m$ and deposition was performed using RF sputter with glancing angle deposition mode. Pt IDEs fabricated by photolithography and dry etching. In comparison with thin film sensor, sensing performance of nanostructure sensor showed an enhanced response of more than 20 times when exposed to 50 ppm acetone at $400^{\circ}C$. Such a remarkable faster response can pave the way for a new generation of exhaled breath analyzers based on chemiresistive sensors which are less expensive, more reliable, and less complicated to be manufactured. Moreover, presented sensor technology has the potential of being used as a personalized medical diagnostics tool in the near future.

• 한국표면공학회지
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• 제49권5호
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• pp.472-476
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• 2016

The nano-array of the vertically aligned rod-like particles grown on ZnO coated glass-substrates was obtained via hydrothermal process. ZnO thin film coatings were prepared on the glass substrates using a MOD (metallorganic deposition) dip-coating method with zinc chloride dihydrate as starting material and 2-ethylhexanol as solvent. ZnO nanorods were synthesized on the seeded substrates by hydrothermal method at $80^{\circ}C$ using zinc-nitrate hexahydrate as a Zn source and sodium hydroxide as a mineralizer. Under the hydrothermal condition, the rod-like nanocrystals were easily attaching on the already ZnO seeded (coated) glass surface. It has been shown that the hydrothermal synthesis parameters are key factors in the nucleation and growth of ZnO crystallites. By controlling of hydrothermal parameters, the ZnO particulate morphology could be easily tailored. Rod-shaped ZnO arrays on the glass substrates consisted of elongated crystals having 6-fold symmetry were predominantly developed at high Zn precursor concentration in the pH range 7~11.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.202.1-202.1
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• 2013

ZnO nanostructure was fabricated on a Si substrate using two-step growth. The seed layer was grown on the Si substrate by a sol-gel spin-coating. In the first step, ZnO nanorods were grown by a hydrothermal method at $140^{\circ}C$ for 5 min. In the second step, a ZnO thin film was grown on the ZnO nanorods by spin-coating. After growth, these films were annealed at $800^{\circ}C$ for 10 min. Electrical and optical properties of ZnO nanostructures have modified by plasma-assisted molecular beam epitaxy (PA-MBE) regrowth. The carrier concentration and resistivity increased by PA-MBE regrowth. In the photoluminescence, the full width at half maximum and intensity were decreased and increased, respectively, by PA-MBE regrowth.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1184-1187
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• 2003

Electrochemical capacitors are becoming attractive energy storage systems particularly for applications involving high power requirements such as hybrid systems consisting of batteries and electrochemical capacitors for electric vehicle propulsion. A new type electric double layer capacitor (EDLC) was constructed by using carbon nanofibers (CNFs) and DAAQ(1,5-diaminoanthraquinone) electrode. Carbonaceous materials are found in variety forms such as graphite, diamond, carbon fibers etc. While all the carbon nanofibers include impurities such as amorphous carbon, nanoparticles, catalytic metals and incompletely grown carbons. We have eliminated of Ni particles and some carbonaceous particles in nitric acid. Nitric acid treated CNFs could be covered with very thin DAAQ oligomer from the results of CV and TG analyses and SEM images. DAAQ oligomer film exhibited a specific capacity as 45-50 Ah/kg in 4M $H_2SO_4$. We established Process Parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured CNFs electrodes using controlled solution chemistry. As a result, CNFs coated by DAAQ composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency.