Fabrication of ordered Ta<sub>2</sub>O<sub>5</sub> nanodots using an anodic aluminum oxide template on Si substrate

Yang, Ching Jung; Chen, Chih; Wu, Pu‐Wei; Shieh, Jia Min; Wang, Shun Min; Liang, S. W.

doi:10.1557/jmr.2007.0143

Cited by 4 publications

(1 citation statement)

References 31 publications

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“…Nanostructured materials, such as quantum dots, nanorods, nanowires, nanotubes, − nanobelts, and nanopores − have attracted much interest due to their potential in various applications. From among the many nanostructured materials, TiO 2 nanostructures have emerged as one of the most promising materials for optoelectronic devices due to their variety of growth methods, high melting point of 1855 °C, thermal and chemical stability at high temperatures, wide and indirect semiconductor band gap, and high photoconversion efficiency and photostability. − As reported in the literature, − a blue-shift phenomenon was observed for the absorption edge with decreasing TiO 2 nanoparticle size.…”

Section: Introductionmentioning

confidence: 99%

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Chang

Liu

Cheng

et al. 2013

ACS Appl. Mater. Interfaces

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2-Dimensional (2-D) TiO2 thin films and 1-dimensional (1-D) TiO2 nanotube arrays were fabricated on Si and quartz substrates using atomic layer deposition (ALD) with an anodic aluminum oxide (AAO) template at 400 °C. The film thickness and the tube wall thickness can be precisely controlled using the ALD approach. The intensities of the absorption spectra were enhanced by an increase in the thickness of the TiO2 thin film and tube walls. A blue-shift was observed for a decrease in the 1-D and 2-D TiO2 nanostructure thicknesses, indicating a change in the energy band gap with the change in the size of the TiO2 nanostructures. Indirect and direct interband transitions were used to investigate the change in the energy band gap. The results indicate that both quantum confinement and interband transitions should be considered when the sizes of 1-D and 2-D TiO2 nanostructures are less than 10 nm.

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Section: Introductionmentioning

confidence: 99%

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Chang

Liu

Cheng

et al. 2013

ACS Appl. Mater. Interfaces

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Fabrication of Anodic Aluminum Oxide Film on Large-Area Glass Substrate

Yang

Liang

et al. 2007

Electrochem. Solid-State Lett.

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Fabrication of anodic aluminum oxide ͑AAO͒ on 4 in. glass substrate was demonstrated. Using unique structure with quadruple contacts as electrode support during anodization, we reported gradual transformation from opaque aluminum to transparent AAO over the entire substrate. In contrast, partial transformation was observed with typical single contact approach where growth of insulating AAO inhibited subsequent anodization by interrupting current flow from the contact point. Results from optical spectroscope revealed moderate reduction in transmittance after AAO formation. Successful development of large-area AAO on glass substrate opens up opportunities for AAO templated devices that require a large footprint.Recently, self-organized nanostructures and devices have received much attention because their unique properties demonstrate considerable potentials in many applications. 1,2 Several techniques are reported to fabricate desirable structures including atomic layer deposition, focused ion-beam etching, and scanning probe-based nanolithography. 3-5 Unfortunately, these approaches are relatively time-consuming, expensive, and in particular confined to substrates with a limited footprint. As a result, alternative methods that are simple and especially suited to large areas are being intensively pursued. One of the promising solutions is to use anodic aluminum oxide ͑AAO͒ as a template to construct the intended nanostructure. The AAO consists of a close-packed hexagonal array of nanopores. Its characteristics could be adjusted by varying process parameters such as operation voltage, temperature, as well as electrolyte type and concentration. 6,7 To date, AAOs with highly ordered pore arrays are routinely prepared with tailored pore diameter and channel length.Several studies have reported growth of AAO film by direct anodization of Al deposited on substrates such as silicon and glass. [8][9][10] This was achieved by successive depositions of conductive underlayer and Al, and followed by typical anodization treatments. The as-synthesized AAO film was then used as the template to develop one-dimensional nanostructures in various oxides and metals. 11,12 From the standpoint of device fabrication, AAO film in large area is always preferred. However, due to lab-scaled experiment, AAO film that has been prepared so far is still confined to a limited area. 13,14 We believe lack of research in large area AAO formation is limiting its implementation in device fabrication of commercial scale.Transparent glass substrate is widely used for applications in photoelectrochemistry and photocatalysis. Owing to its insulating nature, direct anodization of Al on large-area glass substrate presents a serious challenge. Previously, Chu et al. employed tin-doped indium oxide predeposited on the glass substrate as a conductive layer to facilitate complete AAO formation. 15 In contrast, Miney et al. evaporated Al directly on microscope glass slide and reported successful oxidation of Al to AAO. 16 In addition, they noticed a selflimiting...

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Facile Fabrication of TiO₂Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method

Lin

Chang

Chen

2011

J. Electrochem. Soc.

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Self-organized anodic titanium dioxide nanorod arrays were fabricated using a two-stage anodization method from superimposed Ti-Al layers deposited on quartz substrates. The morphology of nanorods could be controlled by the anodizing conditions of the aluminum (first stage) and the titanium layer (second stage). The first stage of anodization process controls the diameter and density of nanorods and the second stage of anodization controls the height of nanorods. Therefore, we could fabricate nanorod arrays with desired aspect ratio and density under specific anodizing conditions. Furthermore, we used TiO2 nanorod arrays as the field ionization anode of a gas sensor, and the morphology of nanorods has shown to have a high correlation with the working voltage of gas sensing. The TiO2 nanorods possess good selectivity and low working voltage under different atmosphere and their working electric field is lower than gas sensing using carbon nanotubes and ZnO nanowires as the anode.

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Fabrication of ordered Ta₂O₅ nanodots using an anodic aluminum oxide template on Si substrate

Cited by 4 publications

References 31 publications

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Fabrication of Anodic Aluminum Oxide Film on Large-Area Glass Substrate

Facile Fabrication of TiO₂Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method

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Fabrication of ordered Ta2O5 nanodots using an anodic aluminum oxide template on Si substrate

Cited by 4 publications

References 31 publications

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO2 Fabricated by Atomic Layer Deposition

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO2 Fabricated by Atomic Layer Deposition

Fabrication of Anodic Aluminum Oxide Film on Large-Area Glass Substrate

Facile Fabrication of TiO2Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method

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Fabrication of ordered Ta₂O₅ nanodots using an anodic aluminum oxide template on Si substrate

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Effect of Geometric Nanostructures on the Absorption Edges of 1-D and 2-D TiO₂ Fabricated by Atomic Layer Deposition

Facile Fabrication of TiO₂Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method