Enhancement of pore size distribution in one-step hybrid pulse anodization of aluminum thin films sputtered on Si substrates

Chung, Chen-Kuei; Liao, Mei-Hsiu; Khor, O. K.; Chang, Hao

doi:10.1016/j.tsf.2013.02.096

Cited by 6 publications

(6 citation statements)

References 28 publications

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“…Nanoporous anodic alumina (NAA) films consisting of regular arrays of high-aspect-ratio nanochannels provide an excellent substrate for tunable biosensors. Nanochannel arrays in alumina can be fabricated with a wide range of geometrical attributes through the control of anodization parameters, and the fabricated nanochannnels are amenable to a range of functionalization. , In addition, fabrication of NAA arrays as thin films on a range of substrates including glass, silicon, PET, and metals enables easy integration into miniaturized, flexible, and portable sensing platforms. Transparent glass with an indium tin oxide (ITO) coating is an ideal substrate material choice, as many optical and electrochemical biosensors , require transparent and conductive substrates.…”

Section: Introductionmentioning

confidence: 99%

Impedance-Based Nanoporous Anodized Alumina/ITO Platforms for Label-Free Biosensors

Devarakonda

Ganapathysubramanian

Shrotriya

2021

ACS Appl. Mater. Interfaces

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We report an experimental and computational approach for the fabrication and characterization of a highly sensitive and responsive label-free biosensor that does not require the presence of redox couples in electrolytes for sensitive electrochemical detection. The sensor is based on an aptamer-functionalized transparent electrode composed of nanoporous anodized alumina (NAA) grown on indium tin oxide (ITO)-covered glass. Electrochemical impedance changes in a thrombin binding aptamer (TBA)-functionalized NAA/ITO/glass electrode due to specific binding of α-thrombin are monitored for protein detection. The aptamer-functionalized electrode enables sensitive and specific thrombin protein detection with a detection limit of ∼10 pM and a high signal-to-noise ratio. The transient impedance of the alumina film-covered surface is computed using a computational electrochemical impedance spectroscopy (EIS) approach and compared to experimental observations to identify the dominant mechanisms underlying the sensor response. The computational and experimental results indicate that the sensing response is due to the modified ionic transport under the combined influence of steric hindrance and surface charge modification due to ligand/receptor binding between α-thrombin and the aptamer-covered alumina film. These results suggest that alumina film-covered electrodes utilize both steric and charge modulation for sensing, leading to tremendous improvement in the sensitivity and signal-to-noise ratio. The film configuration is amenable for miniaturization and can be readily incorporated into existing portable sensing systems.

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Section: Introductionmentioning

confidence: 99%

Impedance-Based Nanoporous Anodized Alumina/ITO Platforms for Label-Free Biosensors

Devarakonda

Ganapathysubramanian

Shrotriya

2021

ACS Appl. Mater. Interfaces

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“…The internal defects of aluminium such as grain boundary were discussed to be the reason of disordered pore formation and the small grain size of aluminium film also limited the pore distance and diameter of PAA. 13 Electrochemical polish is a pretreatment that allows the formation of more uniform PAA. However, it is impossible to perform on aluminum film due to its limited thickness.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of surface morphology on pore structure was seldom been reported despite the fact that it is an important factor in aluminum anodisation. 13 Transparent glass substrate is widely used for applications in photochemistry, photocatalysis and solar energy utilisation, 14 and the insulating nature can be resolved by depositing tin-doped indium oxide (ITO) film on glass substrate as conductive layer. 11 PAA on glass substrate is ideal for the purpose to research the mechanism of laser induced damage of porous optical films.…”

Section: Introductionmentioning

confidence: 99%

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Comparative study of porous anodic alumina: Effects of aluminium deposition methods

Chin

Yam

Chai

et al. 2015

Materials Science and Technology

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This article reports on the comparative study of the fabrication of porous anodic alumina films by anodisation of the aluminium films on glass substrates which were deposited by direct current sputtering and electron beam evaporation methods. The relationship between surface morphology of the deposited aluminum films and porous anodic alumina films was investigated. A more uniform and ordered porous anodic alumina was obtained by fabricating from electron beam evaporation deposited aluminium film with smaller and compact grains. Two-step anodisation was used to further improve the quality of porous anodic alumina compared to one-step anodisation. The optical transmittance spectra within wavelength of 370–800 nm were obtained and the optical properties were studied.

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“…Thus, direct fabricating AAO onto rigid substrates become a more convenient and important technique to prepare vertical nanostructures. The fabrication of AAO on Si substrates has been well established [ 12 - 17 ], while many photonic applications call for nanowire structures on transparent conductive substrates. The tin-doped indium oxide (ITO) glass is a good choice to satisfy this demand [ 18 - 20 ].…”

Section: Introductionmentioning

confidence: 99%

Fast anodization fabrication of AAO and barrier perforation process on ITO glass

et al. 2014

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Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates.

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Enhancement of pore size distribution in one-step hybrid pulse anodization of aluminum thin films sputtered on Si substrates

Cited by 6 publications

References 28 publications

Impedance-Based Nanoporous Anodized Alumina/ITO Platforms for Label-Free Biosensors

Impedance-Based Nanoporous Anodized Alumina/ITO Platforms for Label-Free Biosensors

Comparative study of porous anodic alumina: Effects of aluminium deposition methods

Fast anodization fabrication of AAO and barrier perforation process on ITO glass

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