• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.557-558
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• 2006

The mechanical properties of micro-hardness and internal stress of Ni-Fe alloy thin film made by electrodeposition method have been measured as a function of bath composition and current density. And also the microstructure of $200{\AA}$ Ni-Fi nanowires made using anodic aluminum oxide(AAO) templates by electrodeposition method have been observed by SEM as a function of ultrasonic treatment time and bath composition.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.265.1-265.1
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• 2013

Nanoporous anodic aluminum oxide (AAO), a self-ordered hexagonal array has various applications for nanofabrication such as nanotemplate, and nanostructure. In order to obtain highly-ordered porous alumina membranes, Masuda et al. proposed a two-step anodization process however this process is confined to small domain size and long hours. Recently, alternative methods overcoming limitations of two-step process were used to make prepatterned Al surface. In this work, we confirmed that there is a specific tendency used a PDMS stamp to obtain a pre-patterned Al surface. Using the nanoindentaions of a PDMS stamp as chemical carrier for wet etching, we can easily get ordered nanoporous template without two-step process. This chemical etching method using a PDMS stamp is very simple, fast and inexpensive. We use two types of PDMS stamps that have different intervals (800nm, 1200nm) and change some parameters have influenced the patterning of being anodized, applied voltage, soaking and stamping time. Through these factors, we demonstrated the patterning effect of large scale PDMS stamp.

• Transactions of Materials Processing
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• v.29 no.3
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• pp.127-134
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• 2020

It is known that the difference of texture of the polycrystalline Al sheet is not a critical parameter for the formation of aligned nanopore arrays in anodic aluminum oxide (AAO). This will be related to the polycrystalline grain in the Al sheet. The texture of each grain in the polycrystalline Al sheet is different. The mixed textures of grains have the mixing effects on the nanopore structure of the AAO. Thus, the effect of Al texture on the nanopore structure of the AAO was investigated using three types of Al single crystals with (111), (200) and (220) textures in this paper. These three types of AAO layers were fabricated by the two-step anodizing method at 40 V and temperature of 0-5℃ in oxalic acid solution. In the nanopores formed on the AAO, the average area of one nanopore and the average roundness of one nanopore were measured were measured based on the SEM images. In the hexagon obtained by connecting nanopores on the AAO, the average standard deviation of one angle deviated from 120° was measured. In the AAO nanopores with texture of (111), (200) and (220) single crystal samples, the average area of one nanopore of (200) single crystal sample was the widest, followed by (111), (220) single crystals. The average circularity of one nanopore of (200) single crystal sample was the best, followed by (111), (220) single crystals. The average standard deviation of an angle from 120° of (220) single crystal sample was the largest, followed by (111) and (200) single crystals.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.480-480
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• 2011

양극산화(anodization)는 금속을 전기화학적으로 산화시켜 금속산화물로 만드는 기술로서 최근 다양한 크기의 나노 구조를 제조하는 기술로 각광받고 있으며, 이러한 기술에 의하여 얻어지는 anodic aluminum oxide(AAO)는 magnetic data storage, optoelectronic device, sensor에 적용될 수 있는 nano device 뿐만 아니라 nanostructure를 제조하기 위한 template 및 mask로써 최근 광범위 하게 연구되고 있다. 또한, AAO는 Al2O3의 단단한 구조를 가진 무기재료이므로 solid mask로써 다른 porous materials 보다 뛰어난 특성을 갖고 있다. 또한 electron-beam lithography 및 block co-polymer 에 의한 patterning 과 비교하여 매우 경제적이며, 재현성이 우수할 뿐만 아니라 대면적에서 나노 구조의 크기 및 형상제어가 비교적 쉽기 때문에 널리 사용되고 있다. 그러나, AAO 형성 시 생기게 되는 반구형 모양의 barrier layer는 물질(substance)과 기판과의 direct physical and electrical contact을 방해하기 때문에 해결해야 할 가장 큰 문제점 중 하나로 알려져 있다. 따라서 본 연구에서는 실리콘 기판위의 형성된 AAO의 barrier layer를 Cl/BCl3 gas mixture에서 Neutral Beam Etching (NBE)과 Ion Beam Etching (IBE) 로 각각 식각한 후 그 결과와 비교하였다. NBE와 IBE 모두 Cl2/BCl3 gas mixture에서 BCl3 gas의 첨가량이 60% 일 경우 etch rate이 가장 높게 나타났고, optical emission spectroscopy (OES)로 Cl2/BCl3 플라즈마 내의 Cl radical density와 X-ray photoelectron spectroscopy (XPS)로 AAO 표면 위를 관찰한 결과 휘발성 BOxCly의 형성이 AAO 식각에 크게 관여함을 확인 할 수 있었다. 또한, NBE와 IBE 실험한 다양한 Cl2/BCl3 gas mixture ratio 에서 AAO가 식각이 되지만, 이온빔의 경우 나노사이즈의 AAO pore의 charging에 의해 pore 아래쪽의 위치한 barrier layer를 어떤 식각조건에서도 제거하지 못하였다. 하지만, NBE에서는 BCl3-rich Cl2/BCl3 gas mixture인 식각조건에서 AAO pore에 휘발성 BOxCly를 형성하면서 barrier layer를 제거할 수 있었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.240-243
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• 2009

Recently, many researches on the development of super-hydrophobic and anti-reflective surfaces have been concentrated on the fabrication of nano-patterned products. The nano-patterned mold is a key to replicate nano-patterned products by mass production techniques such as injection molding and UV molding. The present paper proposes fabricating nano-patterned mold with cost-effective method. The nano-pattern molded was fabricated by electroforming the anodic aluminum oxide template without E-beam lithography. The final mold with nano-patterns showed the pores with the diameter of $100{\sim}120$ nm and the height of 150 nm was fabricated.

• Transactions of Materials Processing
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• v.19 no.2
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• pp.73-78
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• 2010

Recently, many researches on the development of super-hydrophobic surface have been concentrated on the fabrication of nano-patterned products. Nano-patterned mold is a key to replicate nano-patterned products by mass production process such as injection molding and UV molding. The present paper proposes the new fabricating method of nano-patterned mold at low cost. The nano-patterned mold was fabricated by electroforming the anodic aluminum oxide membrane filled with UV curable resin in nano-hole by capillary phenomenon. As a result, the final mold with nano-patterns which have the holes with the diameter of 100~200 nm was fabricated. Furthermore, the UV-molded products with clear nano- patterns which have the pillars with the diameter of 100~200nm were achieved.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.166-167
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• 2007

본 연구에서는 Anodic Aluminum Oxide(AAO)-Nano Template 제조 시 알루미늄의 결정방위가 AAO 미세공 형성에 미치는 영향을 연구하였다. 시료는 직경 20mm 두께 2mm의 (200), (220), (111) 세가지 알루미늄 단결정 시편을 사용 하였으며 이는 XRD 장비로 단결정임을 확인 하였다. 양극산화에 앞서 평활한 면을 얻기 위해 다이아몬드 콤파운드($1{\mu}m$)로 미세연마 하였으며 양극산화는 세가지 시편에 대해 모두 동일한 조건에서 2단계 양극산화까지 하였다. 결과는 주사전자현미경(FE-SEM)으로 제조된 AAO 표면의 세공형태와 단면을 모두 관찰 하였으며 그 결과 (200) 결정방위가 (220), (111) 결정 방위보다 세공 형태 균일도 및 단면 정열도와 직진성이 우수함을 관찰 할 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.625-630
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• 2013

The friction behavior of a 60-${\mu}m$-thick anodic aluminum oxide (AAO) film having cylindrical nanopores of 45-nm diameter was investigated as a function of impregnated oil viscosity ranging from 3.4 to 392.6 cSt. Reciprocating ball-on-flat sliding friction tests using a 1-mm-diameter steel ball as the counterpart were carried out with normal load ranging from 0.1 to 1 N in an ambient environment. The friction coefficient significantly decreased with an increase in the oil viscosity. The boundary lubrication film remained effectively under all test conditions when high-viscosity oil was impregnated, whereas it was easily destroyed when low-viscosity oil was impregnated. Thin plastic deformed layer patches were formed on the worn surface with high-viscosity oil without evidence of tribochemical reaction and transfer of counterpart material.

• Journal of Information Display
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• v.2 no.3
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• pp.78-85
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• 2001

The growth of carbon nanotubes(CNTs) in anodic aluminum oxide(AAO) template and their application to a field emitter are described. AAO templates were fabricated by anodizing bulk aluminum and sputtered thin Al film on Nb-coated Si wafers. After Co catalyst had been electrochemically deposited into the bottom of the pores in AAO template, CNTs were grown by pyrolyzing $C_2H_2$. Depending on the reaction conditions, CNTs grew up to or over the top of the pores in AAO template with different structures. The morphology and structure of CNTs were observed with a scanning electron microscope and a transmission electron microscope. The diameter of CNTs strongly depended on the size of the pores in AAO template and the growing conditions. The electron field emission measurement of the samples resulted in the turn-on field of 1.9-2.2 $V/{\mu}m$ and the field enhancement factor of 2450-5200. The observation of high field enhancement factors is explained in terms of low field screening effect.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.349-352
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• 2014

Anodic alumina oxide (AAO), a self-ordered hexagonal array, has various applications in nanofabrication such as the fabrication of nanotemplates and other nanostructures. In order to obtain highly ordered porous alumina membranes, a two-step anodization or prepatterning of aluminum are mainly conducted with straight electric field. Electric field is the main driving force for pore growth during anodization. However, impurities in aluminum can disturb the direction of the electric field. To confirm this, we anodized two different aluminum foil samples with high purity (99.999%) and relatively low purity (99.8%), and compared the differences in the surface morphologies of the respective aluminum oxide membranes produced in different electric fields. Branched pores observed in porous alumina surface which was anodized in low-purity aluminum and the size; dimensions of the pores were found to be usually smaller than those obtained from high-purity aluminum. Moreover, anodization at high voltage proceeds to a significant level of conversion because of the high speed of the directional electric field. Consequently, anodic alumina membrane of a specific morphology, i.e., meshed pore, was produced.