• Macromolecular Research
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• v.16 no.5
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• pp.441-445
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• 2008

A series of aluminum complexes supported by $\beta$-ketoamino, ligand-bearing, 3-position substituents $LAlEt_2$ ($L=CH_3C(O)C(Cl)=C(CH_3)NAr\;(L_1)$, $L=CH_3C(O)C(H)=C(CH_3)NAr\;(L_2)$, $L=CH_3C(O)C(Ph)=C(CH_3)NAr\;(L_3)$, and $L=CH_3C(O)C(Me)=C(CH_3)NAr\;(L_4)$, $Ar=2,6-^iPr_2C6H_3$) were synthesized in situ and employed in the ring-opening polymerization (ROP) of $\varepsilon$-caprolactone ($\varepsilon$-CL) and cyclohexene oxide (CHO). The 3-position substituents on the $\beta$-ketoamino ligand backbone of the aluminum complexes influenced the catalyst activity remarkably for both ROP of $\varepsilon$-CL and CHO. Aluminum $\beta$-ketoamino complexes displayed different catalytic behavior in ROP of $\varepsilon$-CL and CHO. The order of the catalytic activity of $LAlEt_2$ was $L_1AlEt_2$>$L_2AlEt_2$>$L_3AlEt_2$>$L_4AlEt_2$ for ROP of $\varepsilon$-CL, being opposite to the electron-donating ability of the 3-position substituents on the $\beta$-ketoamino ligand, while the order of the catalytic activity for ROP of CHO was $L_1AlEt_2$>$L_3AlEt_2$>$L_4AlEt_2$>$L_2AlEt_2$. The effects of reaction temperature and time on the ROP were also investigated for both $\varepsilon$-CL and CHO.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.427-431
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• 2017

Anodic aluminum oxide (AAO) film has recently attracted much attention as a key material for the fabrication of various nanostructures. A control of anodizing voltage (U) was employed to render different anodic aluminum oxide (AAO) nanostructures with pore diameter ($D_p$) and interpore distance ($D_{int}$) in oxalic acid. In this work, we study the effect of stepwise modulation of anodizing voltages on the shape and dimension of porous structures along the vertical direction and demonstrate the fabrication of hierarchical layers of systematically controlled three-dimensional (3D) pore profile.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.33-33
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• 2010

Recently, a self-organizing process that occurs during the anodization of aluminum in acidic electrolytes has attracted a vast amount of research attentions, coupled with the ever-increasing demand for the development of effective, inexpensive and technologically simple methods for the synthesis of low-dimensional nanostructures over a macroscopic area overcoming many of the drawbacks of conventional lithographic techniques. In this presentation, recent progress in the fabrication of ordered nanoporous anodic aluminum oxide (AAO), including conventional anodization techniques, newly developed pulse anodization, hard anodization processes, and generic approaches to three-dimensional pore structures with periodically modulated diameters. Discussion will also cover the applications of AAO for the development of structurally well-defined extended arrays of low-dimensional nanostructures, such as nanodots, nanotubes, and nanowires, which could be model systems in investigating a diverse range of research problems in chemistry and physics and also be starting materials in realizing advanced electronic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.401-405
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• 2017

Because silicon thin film solar cells have a high absorption coefficient in visible light, they can absorb 90% of the solar spectrum in a $1-{\mu}m$-thick layer. Silicon thin film solar cells also have high transparency and are lightweight. Therefore, they can be used for building integrated photovoltaic (BIPV) systems. However, the contact electrode needs to be replaced for fabricating silicon thin film solar cells in BIPV systems, because most of the silicon thin film solar cells use metal electrodes that have a high reflectivity and low transmittance. In this study, we replace the conventional aluminum top electrode with a transparent aluminum-doped zinc oxide (AZO) electrode, the band level of which matches well with that of the intrinsic layer of the silicon thin film solar cell and has high transmittance. We show that the AZO effectively replaces the top metal electrode and the bottom fluorine-doped tin oxide (FTO) substrate without a noticeable degradation of the photovoltaic characteristics.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2364-2367
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• 2015

In this study, we fabricated an electrolyte-insulator-metal (EIM) device incorporating a high-k Al₂O₃ sensing membrane using a porous anodic aluminum oxide (AAO) through a two-step anodizing process for pH detection. The structural properties were observed by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction patterns (XRD). Electrochemical measurements taken consisted of capacitance-voltage (C-V), hysteresis voltage and drift rates. The average pore diameter and depth of the AAO membrane with a pore-widening time of 20 min were 123nm and 273.5nm, respectively. At a pore-widening time of 20 min, the EIM device using anodic aluminum oxide exhibited a high sensitivity (56mV/pH), hysteresis voltage (6.2mV) and drift rate (0.25mV/pH).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.859-863
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• 2007

Aluminum oxide films were deposited on n-type 6H-SiC(0001) substrates by RF magnetron sputtering technique for MIS devices applications. Well-behaved C-V characteristics were obtained measured in MIS capacitors structures. The calculated interface trap density measured at $300^{\circ}C$ was about $4.6{\times}10^{10}/cm^2\;eV$ in the upper half of the bandgap. The gate leakage current densities of the MIS structures were about $10^{-8}A/cm^2$ and about $10^{-6}A/cm^2$ measured at room temperature and at $300^{\circ}C$ for a ${\pm}1\;MV/cm$, respectively These results indicate that the interface property of this structure is enough quality to MIS devices applications.

• Journal of the Korean Vacuum Society
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• v.22 no.1
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• pp.26-30
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• 2013

For the realization of high-k insulator, aluminum oxide ($Al_2O_3$) was deposited by using an oxygen ion beam assisted deposition (IBAD) during e-beam evaporation. From the thickness of the $Al_2O_3$ layer evaporated with IBAD process, it was possible to investigate the etching effect of ion beam at higher energies during e-beam evaporation. It was also possible to obtain a higher capacitance as a result of IBAD in spite of the reduced thickness of $Al_2O_3$.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.33-33
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• 2011

반도체 산업기술이 발달함에 따라 고청정 공정 환경이 요구되고 있으며, 반도체 공정용 장비에 이용되는 부품 중 양극산화피막법(Anodizing)으로 피막을 성장시킨 anodic aluminum oxide (AAO)부품은 플라즈마에 의해 화학적, 물리적 침식이 발생하여 코팅막과 모재에 손상을 일으키며 코팅막이 깨지거나 박리되면서 다량의 Particle이 생성됨으로써 공정상의 여러 가지 문제를 야기 시킨다고 알려져 있다. 하지만 코팅막을 평가하는 방법은 거의 전무하며 기본물성 측정방법인 피막두께, 내전압, 임피던스, 내식성 측정방법을 통하여 여러 기본물성측정방법으로 부품의 평가기술을 연구하였다. 본 연구에서는 이러한 진공 부품의 하나인 anodic aluminum oxide (AAO)부품샘플을 누설전류 및 내전압 측정하여 샘플의 전기적 특성을 측정하였고, 표면 미세구조의 변화를 관찰하였다. 부식실험으로는 HCl 가스를 발생시켜 부식정도를 알아봤으며, 부식처리와 플라즈마 처리 모두 코팅 막의 손상과 전기적 특성의 감소를 보였다. 진공장비 전극 부품평가의 유익한 평가 항목으로서 플라즈마 데미지를 주는 도중에 실시간으로 부품평가에 따른 Particle을 측정함으로써 ISPM 장비를 이용하여 진공 장비용 코팅부품이 플라즈마공정에서 발생하는 오염입자를 측정할 수 있는 방법을 연구하였다. 이러한 결과를 이용하여 진공공정에서 사용되는 코팅부품이 플라즈마에 의한 손상정도를 정량화 하고 평가방법을 개발하여 진공장비용 공정 중 실시간으로 부품의 성능평가가 가능하고 코팅부품 신뢰성 향상이 가능할 것으로 본다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.329-334
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• 2008

Aluminum oxide films were deposited on n-type GaN substrates by RF magnetron sputtering technique for MIS devices applications using optimized conditions, Well-behaved C - V characteristics were obtained measured in MIS capacitors structures. The calculated interface trap density measured at $300^{\circ}C$ was about $9\times10^{10}/cm^2$ eV in the upper bandgap. The gate leakage current densities of the MIS structures were about $10^{-9}A/cm^2$ and about $10^{-4}A/cm^2$ measured at room temperature and at $300^{\circ}C$ for $a{\pm}1MV/cm$, respectively. These results indicate that the interface property of this structure is enough quality to MIS devices applications.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.133-140
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• 2004

We carried out anodic aluminum oxide (AAO) on a Si and a sapphire substrate. For anodic oxidation of Al two types of specimens prepared were Al(0.5 $\mu\textrm{m}$)!Si and Al(0.5 $\mu\textrm{m}$)/Ti(0.1 $\mu\textrm{m}$)$SiO_2$(0.1 $\mu\textrm{m}$)/GaN(2 $\mu\textrm{m}$)/Sapphire. Surface morphology of Al film was analyzed depending on the deposition methods such as sputtering, thermal evaporation, and electron beam evaporation. Without conventional electron lithography, we obtained ordered nano-pattern of porous alumina by in- situ process. Electropolishing of Al layer was carried out to improve the surface morphology and evaluated. Two step anodizing was adopted for ordered regular array of AAO formation. The applied electric voltage was 40 V and oxalic acid was used as an electrolyte. The reference electrode was graphite. Through the optimization of process parameters such as electrolyte concentration, temperature, and process time, a regular array of AAO was formed on Si and sapphire substrate. In case of Si substrate the diameter of pore and distance between pores was 50 and 100 nm, respectively. In case of sapphire substrate, the diameter of pore and distance between pores was 40 and 80 nm, respectively