Controllable atomic layer deposition of one-dimensional nanotubular TiO2

Meng, Xiangbo; Banis, Mohammad Norouzi; Geng, Dongsheng; Li, Xifei; Zhang, Yong; Li, Ruying; Abou‐Rachid, Hakima; Sun, Xueliang

doi:10.1016/j.apsusc.2012.11.116

Cited by 62 publications

(44 citation statements)

References 58 publications

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“…Sinha et al 40 also measured the growth rate at 160 C, which was 0.68 Å /cycle. The recent work by Meng et al 41 is in better agreement with current work. They measured a growth rate of 0.34 Å /cycle at 150 C on an anodic aluminum oxide surface.…”

Section: Water Processsupporting

confidence: 82%

Low temperature temporal and spatial atomic layer deposition of TiO2 films

Aghaee

Maydannik

Johansson

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Titanium dioxide films were grown by atomic layer deposition (ALD) using titanium tetraisopropoxide as a titanium precursor and water, ozone, or oxygen plasma as coreactants. Low temperatures (80-120 C) were used to grow moisture barrier TiO 2 films on polyethylene naphthalate. The maximum growth per cycle for water, ozone, and oxygen plasma processes were 0.33, 0.12, and 0.56 Å /cycle, respectively. X-ray photoelectron spectrometry was used to evaluate the chemical composition of the layers and the origin of the carbon contamination was studied by deconvoluting carbon C1s peaks. In plasma-assisted ALD, the film properties were dependent on the energy dose supplied by the plasma. TiO 2 films were also successfully deposited by using a spatial ALD (SALD) system based on the results from the temporal ALD. Similar properties were measured compared to the temporal ALD deposited TiO 2 , but the deposition time could be reduced using SALD. The TiO 2 films deposited by plasma-assisted ALD showed better moisture barrier properties than the layers deposited by thermal processes. Water vapor transmission rate values lower than 5 Â 10 À4 g day À1 m À2 (38 C and 90% RH) was measured for 20 nm of TiO 2 film deposited by plasma-assisted ALD.

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Section: Water Processsupporting

confidence: 82%

Low temperature temporal and spatial atomic layer deposition of TiO2 films

Aghaee

Maydannik

Johansson

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…Despite the lower deposition temperature employed in our work [8,10] and the fact that our samples were not annealed after deposition [11,12], our results are in good agreement with those obtained for the same precursors and deposition temperature [16]. The thickness of the ALD deposit can be estimated from TEM images by the measurement of TiO 2 nanotube wall thickness as shown in Figure 2a [12], and it takes values around 5 nm in good agreement with manufacture condition previously indicated.…”

Section: Chemical and Morphological Characterization Of The Nanoporousupporting

confidence: 78%

“…The NPAMs, heated at 200 • C in the reactor chamber, were sequentially exposed to the precursors which were injected into the reactor chamber employing pulsing times of 1 s. In order to allow the gaseous precursors for diffusing through the high aspect ratio pores of both NPAMs, the precursors were kept into the reaction chamber by closing the vacuum pump valve, during exposure times in the range of 45-60 s. To evacuate the excess of unreacted gaseous precursor and reaction by-products from the ALD reaction chamber, a purge during 90 s with Ar flow of 50 sccm was performed between two subsequent precursor pulses. The number of coating cycles was adjusted according to a growth rate of 0.05 nm/cycle [16], in order to adjust the thickness of the TiO 2 -coating layer to around 5 nm.…”

Section: Methodsmentioning

confidence: 99%

Influence of TiO2-Coating Layer on Nanoporous Alumina Membranes by ALD Technique

et al. 2018

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Geometrical, chemical, optical and ionic transport changes associated with ALD of TiO 2 -coating on the porous structure of two nanoporous alumina membranes (NPAMs), which were obtained by the two-step aluminum anodization method but with different pore size and porosity, are presented. Chemical and morphological changes were determined by analyzing XPS spectra and SEM images, showing practically total coverage of the NPAMs surface and leading to a reduction in the geometrical parameters of both samples, while SAED and high resolution TEM measurements allowed us to determine the crystalline structure and thickness of the TiO 2 -coating, with the latter confirmed by depth-profile XPS analysis. Spectroscopic ellipsometry measurements were also carried out in order to detect changes in characteristic optical parameters (refractive index, n, and extinction coefficient, k), due to the TiO 2 -coating of NPAMs. Considering the common application of NPAMs in solute/ion diffusion processes, the effect of the TiO 2 -coverage on electrochemical parameters was analyzed by measuring the concentration potential with a typical model electrolyte (KCl solutions), leading to an increase of the electropositive character for both kinds of samples.

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“…where Q d is in coulomb, A is in cm 2 and V d is in Volt. For example, a decrement of 15 V and an area of 18 cm 2 correspond to an anodizing decrement charge Q d = 0.67 C. Eq.…”

Section: Quantitative Model Of Barrier Etchingmentioning

confidence: 99%

“…Porous anodic alumina (PAA) membranes provide useful templates for fabricating nanostructures, such as nanowires, 1 nanotubules, 2 nanorods, 3 nanotubes, 4 and nanodots, 5 which can be exploited in technological applications. Current applications include, among others, human blood filters, 6 micrometer and nanometer filters, 7 and solar cells.…”

mentioning

confidence: 99%

Etching the Oxide Barrier of Micrometer-Scale Self-Organized Porous Anodic Alumina Membranes

Bellemare

Carignan

Sirois

et al. 2015

J. Electrochem. Soc.

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We develop a quantitative model to calculate the optimal experimental conditions for the etching of the oxide barrier of porous anodic alumina (PAA) membranes. The method is applied to a membrane fabricated at 370 V in a solution of 2% citric acid. The process creates a network of small pores at the bottom of the larger pores, which accelerates the oxide barrier etching relatively to the pore walls of the PAA membranes, when etched in a solution of phosphoric acid. The oxide barrier etching is confirmed by observation of PAA membranes using scanning electron microscopy, revealing the formation of the small pores and the preferential etching of the bottom of the pores rather than the pore walls. The proposed method, which leads to a better control over the fabrication of nanoporous templates, can be adapted to oxide barriers of different PAA membranes formed at different voltages and in different acids. 8 The PAA membranes, which are fabricated by electrochemical processes, exhibit a hexagonal array of vertical pores that are open on their surface and closed by an oxide barrier at the bottom. In order to obtain PAA membranes that are open on both sides, such as required in filter applications or when electrodepositing nanowires, one needs to develop a strategy for removing the oxide on the bottom side.Several articles proposed methods to etch the oxide barrier of PAA membranes, each with their advantages and disadvantages. Han et al. reported a straightforward method to etch the oxide barrier by first removing the PAA membranes from the growth foil, then by covering the open side with a protective polymer made of nitrocellulose and polyester resin, and finally by etching the membrane in phosphoric acid, 5 wt% at 30• C, until the dissolution of the oxide barrier. While this method is relatively simple and applicable to membranes grown at any voltage, that is, with various geometrical parameters, it requires the application of a protective polymer and its subsequent removal, a delicate operation since the membrane is quite fragile. Also, the polymer can contaminate the membrane. This method has been used in our group to fabricate arrays of ferromagnetic nanowires. 10Nielsch et al.11 exploited the natural chemical widening of the pores of PAA membranes in order to decrease the voltage required for anodization due to the oxide barrier being thinner and allowing the formation of smaller pores in the oxide barrier. Their application of a constant current of 0.29 A/cm 2 during 15 min., followed by a constant current of 0.135 A/cm 2 also during 15 minutes, yielded a network of small open pores at the bottom surface. With this interesting insitu method, the oxide layer is not always completely removed, but rather pierced, and it is also difficult to obtain the desired pore size, due to the initial chemical widening. This method was also used with membranes fabricated at 40 V, but no indication about how to extend it to other anodization voltages is provided in the paper.Another approach used by Zhao et al. 12 is to etc...

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Controllable atomic layer deposition of one-dimensional nanotubular TiO2

Cited by 62 publications

References 58 publications

Low temperature temporal and spatial atomic layer deposition of TiO2 films

Low temperature temporal and spatial atomic layer deposition of TiO2 films

Influence of TiO2-Coating Layer on Nanoporous Alumina Membranes by ALD Technique

Etching the Oxide Barrier of Micrometer-Scale Self-Organized Porous Anodic Alumina Membranes

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