X-ray analysis of nanoporous TiO2 synthesized by electrochemical anodization

Cheong, Y.L.; Yam, F.K.; Chin, IR; Hassan, Z.

doi:10.1016/j.spmi.2013.09.016

Cited by 11 publications

(5 citation statements)

References 28 publications

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“…These results demonstrate that the presence of both hexagonal and cubic phases at the same time induces compression in the lattice of each phase and hinders the growth of larger particles. Similar correlation between the compressive strain and crystallite sizes was reported by Cheong et al in their study of TiO 2 thin films [24]. Reyes-Rojas et al reported that the addition of ZrO 2 and Y 2 O 3 increased the compressive strain in alumina polycrystal and affected the grains growth [25].…”

Section: Effect Of Magnesium Concentration On the Zn (1-x) Mg X O Strsupporting

confidence: 81%

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Mahdjoub¹,

Hafid²,

Aida³

et al. 2017

Semicond. Phys. Quantum Electron. Optoelectron.

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Zn (1-x) Mg x O thin films with various concentrations of magnesium were deposited using the spray pyrolysis method. The transmittance spectra recorded for all films exhibit maxima exceeding 90%. The band gap energy of the films with wurtzite structure increases from 3.22 up to 3.60 eV by incorporating Mg into ZnO. However, when the atomic ratio of Mg exceeded 0.4, a second crystalline phase (assigned to cubic MgO) became discernable in XRD patterns, a compressive strain was observed in the wurtzite lattice, and crystallite sizes decreased significantly. In accordance with these observations, finer grains with a pronounced columnar growth were observed in 3D AFM representations and the surface roughness decreases significantly. Finally, selective etching in water yields to porous films with a great surface-to-volume ratio, a lower refractive index and a better light transmission. These porous films with tunable band gap seem to be excellent candidates to various interesting applications.

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Section: Effect Of Magnesium Concentration On the Zn (1-x) Mg X O Strsupporting

confidence: 81%

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Mahdjoub¹,

Hafid²,

Aida³

et al. 2017

Semicond. Phys. Quantum Electron. Optoelectron.

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“…Based on the data collected from XRD measurements, the mean crystallite size of the samples can be calculated by using Scherrer equation [39], D ¼ ðkkÞ=ðb cos hÞ, where D is the mean crystallite size, k corresponded to shape factor which is reported as 0.9 in literature [40,41], k is the K-alpha1 wavelength which is 0.15406 nm, b corresponded to the full width half maximum and h is the diffraction angle of the dominant diffraction peak. Since plane (101) is the dominant peak of anatase phase, diffraction angle of anatase (101) will be applied as h for crystallite size calculation based on aforementioned.…”

Section: Structural Propertiesmentioning

confidence: 99%

Fabrication of titanium dioxide nanotubes in fluoride-free electrolyte via rapid breakdown anodization

et al. 2015

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This paper presents the study on the growth of bundled titanium dioxide (TiO 2 ) nanotubes via rapid breakdown anodization method by using chloride-based electrolyte. The effects of different ratios of deionized water (DI) to ethylene glycol (EG) on the morphological, structural and photoelectrochemical properties of the TiO 2 nanotubes generated were investigated. Different ratios of DI:EG showed significant changes on the diameter of nanotube bundles. Besides that, X-ray diffraction measurements revealed that anatase phase of titanium dioxide appeared within the thermally treated samples. Scherrer method was applied to calculate the mean crystallite size of the crystal growth in this study. The photoelectrochemical properties of TiO 2 nanotube bundles were characterized by using three-electrode photoelectrochemical cell and showed good photocurrent response and stability.

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“…As it was mentioned, the valence band maximum of the two dimensional new TiO 2 phase has significant Ti 4sp character like other known TiO 2 phases and there was no bandgap states related to O vacancies or titanium sub‐oxides, such as Ti 2 O 3 , which both exhibit mainly Ti 3d character at the highest occupied levels. Our measured bandgap is higher as the nanostructure developed here is substantially different and the surface states of the nanotubular TiO 2 may be caused by strain in the sample due to the nanotube geometry the effect of which on the bandgap has been reported in the literature for the TiO 2 nanotubes …”

Section: Resultsmentioning

confidence: 58%

Structural Defect‐Induced Bandgap Narrowing in Dopant‐Free Anodic TiO₂ Nanotubes

et al. 2017

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The application of TiO 2 in energy-harvesting materials has been restricted, owing to its relatively large bandgap. In accordance with theoretical predictions of lower bandgap and higher absorbance of visible light in TiO 2 nanotube arrays, we demonstrate experimentally that large-area TiO 2 nanotube arrays produced either by low-temperature anodization or by two-step anodization on electropolished Ti exhibit a narrowed bandgap; reducing the bandgap from 3.2 to 2.92 eV in an amorphous (as-anodized) state and to 2.84 eV in the anatase (annealed) phase. The bandgap energy of oxide nanotubes was measured by calculating Tauc plots, according to the diffuse reflectance spectra. Furthermore, the band structure of the TiO 2 nanotube arrays measured by using X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy revealed similar bandgap narrowing evidence. This bandgap narrowing behavior can be attributed to either surface edge states, owing to the incorporation of oxygen atoms on the high surface area of the nanotubes, or the formation of Ti 3 + defect states form nonbonding states within the bandgap below the Fermi-level edge. Annealing the tubes further reduced the energy bandgap, owing to the formation of anatase crystalline phase.

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X-ray analysis of nanoporous TiO2 synthesized by electrochemical anodization

Cited by 11 publications

References 28 publications

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Fabrication of titanium dioxide nanotubes in fluoride-free electrolyte via rapid breakdown anodization

Structural Defect‐Induced Bandgap Narrowing in Dopant‐Free Anodic TiO₂ Nanotubes

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X-ray analysis of nanoporous TiO2 synthesized by electrochemical anodization

Cited by 11 publications

References 28 publications

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

An original way to obtain porous Zn(1–x)MgxO thin films by spray pyrolysis technique

Fabrication of titanium dioxide nanotubes in fluoride-free electrolyte via rapid breakdown anodization

Structural Defect‐Induced Bandgap Narrowing in Dopant‐Free Anodic TiO2 Nanotubes

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Structural Defect‐Induced Bandgap Narrowing in Dopant‐Free Anodic TiO₂ Nanotubes