• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.448-448
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• 2009

기존에 박막공정을 이용한 CIGS 태양전지는 단가가 비싸고 공정이 복잡한 단점이 있다. 따라서 후막형 CIGS 태양전지 위한 CIGS 나노 입자의 필요성이 대두 되었다. CIGS 나노 입자를 합성하기 위한 방법은 용매열법, 콜로이달법 등이 있다. 특히 이들 방법 중에서 열용매 방식은 입도 제어가 용이하고 저압, 저온에서 간단한 공정으로 입자를 합성할 수 있다는 잠정으로 인해 많이 사용되어지고 있다. 본 연구에서는 열용매법을 이용하여, 용매양, 반응온도, 반응시간 등을 통하여 후막형 CIGS에 적합한 나노 입자를 합성하였다. XRD를 통해 상을 분석하고, SEM, 입도, B.E.T.를 통해 파우더의 평가하였다.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.79-81
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• 2002

ZnO 나노와이어는 ZnO 파우더를 볼밀 처리하여 열증착 방법으로 $1380^{\circ}C$에서 촉매없이 Si 기판위에서 합성되었다. 합성된 ZnO 나노와이어의 길이와 직경은 $20{\sim}30{\mu}m$와 $50{\sim}200$ nm 였다. ZnO 나노와이어 표면을 atomic layer deposition(ALD) 방법으로 $Al_2O_3$ 박막을 얇게 코팅하였다. 성장온도는 $300^{\circ}C$였고, 사용한 전구체는 Trimethlaluminum(TMA)와 distilled water($H_2O$) 이다. Transmission electron microscopy(TEM) 으로 측정한 $Al_2O_3$ 박막의 두께는 40 nm 로서 매우 균일하게 ZnO 나노와이어에 증착되었음을 알 수 있었다.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.538-543
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• 2008

Recently a nano-scale diamond is possible to manufacture forms of powder(below 100 nm) by new processing of explosion or deposition method. Using a sintering of nano-scale diamond is possible to manufacture of grinding tools. We have need of a processing development of coated uniformly inorganic to prevent an abnormal grain growth of nano-crystal and bonding obstacle caused by sintering process. This paper, in order to improve the sintering property of nano-scale diamond, we coated ZnO thin films(thickness: $20{\sim}30\;nm$) in a vacuum by ALD(atomic layer deposition) Economically, in order to deposit ZnO all over the surface of nano-scale diamond powder, we used a new modified fluidized bed processing replaced mechanical vibration effect or fluidized bed reactor which utilized diamond floating owing to pressure of pulse(or purge) processing after inserted diamond powders in quartz tube(L: 20 mm) then closed quartz tube by porosity glass filter. We deposited ZnO thin films by ALD in closed both sides of quartz tube by porosity glass filter by ALD(precursor: DEZn($C_4H_{10}Zn$), reaction gas: $H_2O$) at $10^{\circ}C$(in canister). Processing procedure and injection time of reaction materials set up DEZn pulse-0.1 sec, DEZn purge-20 sec, $H_2O$ pulse-0.1 sec, $H_2O$ purge-40 sec and we put in operation repetitive 100 cycles(1 cycle is 4 steps) We confirmed microstructure of diamond powder and diamond powder doped ZnO thin film by TEM(transmission electron microscope) Through TEM analysis, we confirmed that diamond powder diameter was some $70{\sim}120\;nm$ and shape was tetragonal, hexagonal, etc before ALD. We confirmed that diameter of diamond powders doped ZnO thin film was some $70{\sim}120\;nm$ and uniform ZnO(thickness: $20{\sim}30\;nm$) thin film was successfully deposited on diamond powder surface according to brightness difference between diamond powder and ZnO.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.177-182
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• 2020

In this study, the effect of nanofibers in cement pastes on the compressive and tensile strength of hardened cement pastes was studied. Two types of nanofibers, nylon 66 nanofibers and carbon nanotube-nylon 66 hybrid nanofibers, were manufactured by electrospinning methodology and mixed in cement powder respectively. The specimens for experiments were prepared by water to cement ratio of 0.5 and cured in water for 28 days. The effect of nanofibers on the increase of the compressive and tensile strength were confirmed by the experimental results. The well-linking effect of nanofibers in the microstructure of the hardened cement pastes has been found by scanning electron microscope (SEM) analysis and well-explained for the increase in mechanical strength. Besides, field emission transmission electron microscope (FE-TEM) analysis and thermal gravimetric analysis (TGA) have also been conducted to analyze the properties of nanofibers as well as the microstructure of the hardened modified cement pastes.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.123-128
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• 2017

Nanostructured materials have received attention due to their unique electronic, optical, optoelectrical, and magnetic properties as a results of their large surface-to-volume ratio and quantum confinement effects. Thermal chemical vapor deposition process has attracted much attention due to the synthesis capability of various structured nanomaterials during the growth of nanostructures. In this study, silicon oxide nanowires were grown on Si\$SiO_2$(300 nm)\Pt(5~40 nm) substrates by two-zone thermal chemical vapor deposition with the source material $TiO_2$ powder via vapor-liquid-solid process. The morphology and crystallographic properties of the grown silicon oxide nanowires were characterized by field-emission scanning electron microscope and transmission electron microscope. As results of analysis, the morphology, diameter and length, of the grown silicon oxide nanowires are depend on the thickness of the catalyst films. The grown silicon oxide nanowires exhibit amorphous phase.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.127-133
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• 2005

Manufacturing methods of Nano particles can be distinguished by top-down technology as physical method and bottom-up technology as chemical synthetic method. Top-down technology is a kind of method for making microstructure as like carving after forming a macroscopic structure in advance and its typical methods are ball milling, gas condensation method and so on. Nano Particles synthesized by bottom-up method have got to do dispersing process for using them as actual nano particles because their viscosity are very strong and so easy to shape cohesive substances. Therefore, this study is about a particle separating device which separates a certain constant size of grains processed already in mill and mixer because we mostly use media agitating mill as a device of milling and dispersing and we necessarily use very slight balls as media for manufacturing nano particles in the machine. The centrifugal device has been designed for passing and separating below a certain type of grain size after final process of particles in the mill.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.183-184
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• 2005

In this study, our varistors based on M.Matsuoke's composition were fabricated with ZnO nano-powder whose sizes were 50nm and 100nm. Electrical properties of ZnO nano-powder varistors were obtained by capacitance-voltage and frequency-real impedance. nano-powder varistors are indicated the change of the interface defects density $N_t$ at the grain boundaries and the donor concentration $N_d$ in the ZnO grains. Frequency analysis was accomplished to understand the equivalent circuit.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.339-344
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• 2008

Titanium dioxide nanotubes were fabricated by self-organized electrochemical potentiostatic anodization of titanium thin film with an electrolyte solution of sodium sulfate 1M and sodium flouride 0.5wt% aqueous solution at 20$^{\circ}C$ for 20min. Field Emmision Scanning Electron Microscopy(FE-SEM) and X-ray Diffractometer(XRD) were used to evaluate the micromorphology and crystalline structure of the titanium dioxide nanotube thin film. Titanium dioxide nanotube were fabricated with diameters approx. 100nm and tube length from appox. 1 $\mu$m. Titanium dioxide films formed through anodization and annealing process at 450$^{\circ}C$ contained a phase of anatase. Also, this study was performed to evaluate the application of titanium dioxide thin film for treating humic acid dissolved in water. The reaction tended to follow the Langmuir-Hinshelwood kinetics with zero order. Comparative experiments with thin film and anatase powder showed the same zero order kinetics when 0.3g of powder had been used.

• Composites Research
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• v.27 no.6
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• pp.219-224
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• 2014

Nancomposites manufacture has been developed rapidly, because of reinforcing effects of CNT in terms of mechanical, electrical and thermal properties. In this study, 10 wt% CNT paste was fabricated with good dispersion state and easy processability. Damage sensing and reinforcing effect of CNT paste were investigated in nanocomposites. 10 wt% CNT paste exhibited better tensile and flexural properties than those of general 1 wt% CNT nanocomposites. To observe the healing effect of CNT paste, a crack was made artificially with 30wt% CF30wt%/PP composites, and the CNT paste was filled inside the crack. The damage sensing of CNT paste in CF30wt%/PP composites was investigated by electrical resistance measurement and mechanical tests. CNT paste exhibited good reinforcing effect in mechanical properties of CF30wt%/PP composites, and this reinforcing effect was getting better with larger cracks. The reason was because CNT paste had good interfacial adhesion with CF30wt%/PP composites to resist crack propagation. In electrical resistance measurement, there was a jump in electrical resistance signal at the adhesion interface. The jumping signal could be used to predict fracture of CF/PP composites. CNT nanocomposites for damage sensing had crack reducing effect and damage detection using electrical resistance method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.30.2-30.2
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• 2009

TiO2는 3가지의 결정구조를 가지고 있으며 결정 입자, 구조, 상의 형태에 따라서 성질 및 기능에 영향을 주고 있다. anatase상의 애너지 밴드갭과 전자와의 재결합 확률이 크기 때문에 Rutile상 보다 우수한 성질을 갖고 있어 산화물 반도체로 이용하는 것이 적합하다. 본 실험에서는 나노로드의 TiO2를 수열처리법에 의해 합성한 후 박막을 제조하여 감응특성을 조사하였다. X선 회절분석기(X-Ray Diffraction)로 분석결과 ph=1의 루타일상을 제외하고, pH=2~7의 더 넓은 구간에서 뚜렷한 회절피크의 anatase 상이 나타났으며 다른 비정질상이 발생되지 않는 결정성이 좋은 단결정임이 나타났다. NaOH solution 을 이용하여 수열처리후 $180^{\circ}C$이상의 특정 온도 구간에서 수십 나노 로드 형태로의 2차 성장된 모습을 TEM과 EDS로 결정구조와 화학조성을 분석하였다. 그리고 BET 측정을 통해 $180^{\circ}C$의 소성온도에서 TiO2 입자의 비표면적이 가장 우수한 것으로 나타났다. 나노로드의 수용액을 Al2O3기판의 감지막 위에 떨어뜨려 네트워크된 막을 형성한후에 센서를 제작하였다. 히터 전압이 $400^{\circ}C$에서 나노 파우더센서에서는 반응이 일어나지 않은 반면, 나노 로드센서는 CH3SH에서 28% 의 높은 감도를 얻었고, Toluene의 반응에서는 15%의 감도가 나타났다. 그 외 NO, CO, H2등의 측정에서 아무런 반응이 일어나지 않았다. 이는 비교적 기공이 큰분자(Size)를 가진 CH3SH=76nm, Toluene=60nm에서 반응이 일어난 반면, H2=28nm, CO=22nm에서 감도가 나타나지 않은 것을 보아 흡착분자크기에 의한 영향이 큰 것으로 나타났다.