Anodized aluminum oxide membranes of tunable porosity with platinum nanoscale-coating for photonic application

Yuhai Zhang,손상준,주형규 한국물리학회 2012 Current Applied Physics Vol.12 No.6

We fabricate anodized aluminum oxide (AAO) membranes with platinum (Pt) coating of various thickness ranging from 0 nm to 12 nm. We also demonstrate the tunability of membrane porosity, to add a degree of freedom in addition to the Pt coating, for optical modulation that can be used in photonic application. The reflectance measurement and its analysis are provided based on FabryePerot etalon optics that takes into account spectral dependence of optical absorption and loss in the AAO membrane. It is revealed that the frequency-dependent optical finesse (color purity) enhances nonlinearly with the Pt thickness, by the quantitative estimation, while the effective refractive index is substantially governed by the membrane porosity. These features can allow for the AAO membrane to be used as a dye-free color displaying film with efficient tunability of both displaying color and its color purity. In particular, the strong dependence of an effective refractive index on porosity is demonstrated such that the AAO membrane can have the effective refractive index down to about 1.2, making it a possible candidate for a single layer anti-reflection coating material deposited on optical components including low-index glass. We also fabricate, by facile dipping method, an AAO membrane whose pore size changes gradually along a direction on its surface. This intra-membrane modulation of porosity allows it to find application in an optical grating or band-pass filter whose transmission wavelength varies with position on the device surface. We fabricate anodized aluminum oxide (AAO) membranes with platinum (Pt) coating of various thickness ranging from 0 nm to 12 nm. We also demonstrate the tunability of membrane porosity, to add a degree of freedom in addition to the Pt coating, for optical modulation that can be used in photonic application. The reflectance measurement and its analysis are provided based on FabryePerot etalon optics that takes into account spectral dependence of optical absorption and loss in the AAO membrane. It is revealed that the frequency-dependent optical finesse (color purity) enhances nonlinearly with the Pt thickness, by the quantitative estimation, while the effective refractive index is substantially governed by the membrane porosity. These features can allow for the AAO membrane to be used as a dye-free color displaying film with efficient tunability of both displaying color and its color purity. In particular, the strong dependence of an effective refractive index on porosity is demonstrated such that the AAO membrane can have the effective refractive index down to about 1.2, making it a possible candidate for a single layer anti-reflection coating material deposited on optical components including low-index glass. We also fabricate, by facile dipping method, an AAO membrane whose pore size changes gradually along a direction on its surface. This intra-membrane modulation of porosity allows it to find application in an optical grating or band-pass filter whose transmission wavelength varies with position on the device surface.

양극산화를 이용한 알루미나 나노세공 멤브레인의 제조

임완순,조경철,조유석,최규석,김도진,Im, W.S.,Cho, K.C.,Cho, Y.S.,Choi, G.S.,Kim, D.J. 한국재료학회 2003 한국재료학회지 Vol.13 No.9

Anodic aluminum oxide (AAO) membrane was made of aluminum sheet (99.6%, 0.2 mm thickness). The regular array of hexagonal nano pores or channels were prepared by two step anodization process. A detail description of the AAO fabrication is presented. After the 1st anodization in oxalic acid (0.3 M) at 45 V, The formed AAO was removed by etching in a solution of 6 wt% $H_3$$PO_4$+1.8 wt% $H_2$$CrO_4$. The regular arrangement of the pores was obtained by the 2nd anodization, which was carried out in the same condition as the 1st anodization. Subsequently, the alumina barrier layer at the bottom of the channel layer was removed in phosphoric acid (1M) after removing of aluminum. Pore diameter, density, and thickness could be controlled by the anodization process parameters such as applied voltage, anodizing time, pore widening time, etc. The pore diameter is proportional to the applied voltage and pore widening time. The pore density and thickness can be controlled by anodization temperature and voltage.

High Density Silver Nanowire Arrays using Self-ordered Anodic Aluminum Oxide (AAO) Membrane

김용현,한용환,이형직,이형복 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.4

Highly ordered silver nanowire with a diameter of 10 nm was arrayed by electroless deposition in a porous anodic aluminum oxide (AAO) membrane. The AAO membrane was fabricated electrochemically in an oxalic acid solution via a two-step anodization process, while growth of the silver nanowire was initiated by using electroless deposition at the long-range-ordered nanochannels of the AAO membrane followed by thermal reduction of a silver nitrate aqueous solution by increasing the temperature up to 350oC for an hour. An additional electro-chemical procedure was applied after the two-step anodization to control the pore size and channel density of AAO, which enabled us to fabricate highly-ordered silver nanowire on a large scale. Electroless deposition of silver nitrate aqueous solution into the AAO membrane and thermal reduction of silver nanowires was performed by increasing the temperature up to 350oC for 1 h. The morphologies of silver nanowires arrayed in the AAO membrane were investigated using SEM. The chemical composition and crystalline structure were confirmed by XRD and EDX. The electrolessdeposited silver nanowires in AAO revealed a well-crystallized self-ordered array with a width of 10 nm. Highly ordered silver nanowire with a diameter of 10 nm was arrayed by electroless deposition in a porous anodic aluminum oxide (AAO) membrane. The AAO membrane was fabricated electrochemically in an oxalic acid solution via a two-step anodization process, while growth of the silver nanowire was initiated by using electroless deposition at the long-range-ordered nanochannels of the AAO membrane followed by thermal reduction of a silver nitrate aqueous solution by increasing the temperature up to 350oC for an hour. An additional electro-chemical procedure was applied after the two-step anodization to control the pore size and channel density of AAO, which enabled us to fabricate highly-ordered silver nanowire on a large scale. Electroless deposition of silver nitrate aqueous solution into the AAO membrane and thermal reduction of silver nanowires was performed by increasing the temperature up to 350oC for 1 h. The morphologies of silver nanowires arrayed in the AAO membrane were investigated using SEM. The chemical composition and crystalline structure were confirmed by XRD and EDX. The electrolessdeposited silver nanowires in AAO revealed a well-crystallized self-ordered array with a width of 10 nm.

High Density Silver Nanowire Arrays using Self-ordered Anodic Aluminum Oxide(AAO) Membrane

Kim, Yong-Hyun,Han, Young-Hwan,Lee, Hyung-Jik,Lee, Hyung-Bock The Korean Ceramic Society 2008 한국세라믹학회지 Vol.45 No.4

Highly ordered silver nanowire with a diameter of 10 nm was arrayed by electroless deposition in a porous anodic aluminum oxide(AAO) membrane. The AAO membrane was fabricated electrochemically in an oxalic acid solution via a two-step anodization process, while growth of the silver nanowire was initiated by using electroless deposition at the long-range-ordered nanochannels of the AAO membrane followed by thermal reduction of a silver nitrate aqueous solution by increasing the temperature up to $350^{\circ}C$ for an hour. An additional electro-chemical procedure was applied after the two-step anodization to control the pore size and channel density of AAO, which enabled us to fabricate highly-ordered silver nanowire on a large scale. Electroless deposition of silver nitrate aqueous solution into the AAO membrane and thermal reduction of silver nanowires was performed by increasing the temperature up to $350^{\circ}C$ for 1 h. The morphologies of silver nanowires arrayed in the AAO membrane were investigated using SEM. The chemical composition and crystalline structure were confirmed by XRD and EDX. The electroless-deposited silver nanowires in AAO revealed a well-crystallized self-ordered array with a width of 10 nm.

박막 알루미늄을 이용한 규칙적으로 정렬된 나노급 미세기공 어레이 제조기술 개발

이재홍,김창교,Lee, Jae-Hong,Kim, Chang-Kyo 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.8

An alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer was fabricated. It Is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. While the oxalic acid with 0.2 M was used for low voltage anodization under 100 V, the chromic acid with 0.1 M was used for high voltage anodization over 100 V. The nano-sized pores with diameter of $60\~120$ nm was obtained by low voltage anodization of $40\~80$ V and those of $200\~300$ nm was obtained by high voltage anodization of $140\~200$ V. The pore widening process was employed for obtaining the one-channel with flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1 M concentration to etching the barrier layer.

Fabrication of Nanoporous Aluminum-oxide Composite Membranes

Balasankar Athinarayanan,정대영,강종현,구봉호 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.12

To overcome the poor mechanical property of anodic aluminum-oxide (AAO) membranes, we tried to develop AAO/Al composite membranes consisting of membrane cells with straight-pore channels of 40 to 100 nm in diameter and a mesh-like pattern acting as a supporting layer by using UV-light lithography followed by wet-etching for the formation of a mesh-like pattern and anodic oxidation followed by wet-etching for the formation of nano-pores with desired specifications. As a result, AAO/Al composite membranes with breaking pressures of over 5 bar, which is an upper bound for ultra- and micro-filtration, could be fabricated. An AAO/Al composite membrane with a water permeability as high as 130 L/m2·h·bar could be fabricated. The composite membranes developed in the present study can be used in micro- and ultra-filtration of severe environments with relatively high economic efficiency and large margins in the flow rate and the breaking pressure.

Electrically Actuatable Smart Nanoporous Membrane for Pulsatile Drug Release

Jeon, Gumhye,Yang, Seung Yun,Byun, Jinseok,Kim, Jin Kon American Chemical Society 2011 NANO LETTERS Vol.11 No.3

<P>We report on the fabrication of electrically responsive nanoporous membrane based on polypyrrole doped with dodecylbenzenesulfonate anion (PPy/DBS) that was electropolymerized on the upper part of anodized aluminum oxide membrane. The membrane has regular pore size and very high pore density. Utilizing a large volume change of PPy/DBS depending on electrochemical state, the pore size was acutated electrically. The actuation of the pores was experimentally confirmed by in situ atomic force microscopy and in situ flux measurement. We also demonstrated successfully pulsatile (or on-demand) drug release by using fluorescently labeled protein as a model drug. Because of a fast switching time (less than 10 s) and high flux of the drugs, this membrane could be used for emergency therapy of angina pectoris and migraine, which requires acute and on-demand drug delivery, and hormone-related disease and metabolic syndrome.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2011/nalefd.2011.11.issue-3/nl104329y/production/images/medium/nl-2010-04329y_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl104329y'>ACS Electronic Supporting Info</A></P>

A Study on the Surface Modification of Anodic Aluminum Oxide Membrane and Its Hydraulic Performance

Anugrah Andisetiawan,NguyenThi Phuong,Jeong Hwan Kim,Yeong-Eun Yoo,Doo-Sun Choi,Jae Sung Yoon 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

Study of Fabrication Process for Janus Membrane based on Anodic Aluminum Oxide

Anugrah Andisetiawan,Jeong Hwan Kim(김정환),Yeong-Eun Yoo(유영은),Doo-Sun Choi(최두선),Jae Sung Yoon(윤재성) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

전자빔 증발법 박막 증착을 이용한 양극 산화 알루미늄 템플릿의 나노 포어 가공 연구

이승훈(Seung-Hun Lee),이민영(Minyoung Lee),김천중(Chunjoong Kim),김관오(Kwanoh Kim),윤재성(Jae Sung Yoon),유영은(Yeong-Eun Yoo),김정환(Jeong Hwan Kim) 한국표면공학회 2021 한국표면공학회지 Vol.54 No.1

The fabrication of nanopore membrane by deposition of Al₂O₃ film using electron-beam evaporation, which is fast, cost-effective, and negligible dependency on substance material, is investigated for potential applications in water purification and sensors. The decreased nanopore diameter owing to increased wall thickness is observed when Al₂O₃ film is deposited on anodic aluminum oxide membrane at higher deposition rate, although the evaporation process is generally known to induce a directional film deposition leading to the negligible change of pore diameter and wall thickness. This behavior can be attributed to the collision of evaporated Al₂O₃ particles by the decreased mean free path at higher deposition rate condition, resulting in the accumulation of Al₂O₃ materials on both the surface and the edge of the wall. The reduction of nanopore diameter by Al₂O₃ film deposition can be applied to the nanopore membrane fabrication with sub-100 nm pore diameter.