Electronic and crystallographic structure of γ-alumina thin films

Ealet, B.; Elyakhloufi, M.H.; Gillet, E.; Ricci, Maria Antonietta

doi:10.1016/0040-6090(94)90171-6

Cited by 230 publications

(135 citation statements)

References 27 publications

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“…This value is lower than those calculated for the alumina nanocage and nanotube ( > 8 eV) (Figure 3). Since there is no experimental evidence about the electronic structure of the SANC in the literature, this value is comparable to the experimentally measured ∆ E gap for the bulk structure of γ -alumina (7.0 eV) 51 and α -alumina (8.8 eV).…”

Section: A G (-730)supporting

confidence: 63%

Density functional study of the structure and water adsorption activity of an Al$_{30}$O$_{30}$ star-shaped alumina nanocage

Zamani¹

2016

Turk J Chem

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Molecular and electronic structures of a novel Al 30 O 30 star-shaped alumina nanocage (SANC) were studied using the recently developed CAM-B3LYP density functional method. Comparison of the stretching vibrational modes of this compound with the corresponding modes related to an Al 20 O 30 perfect cage and Al 50 O 75 tubular alumina nanomaterials showed a shift to lower frequencies, while the bending modes moved to higher frequencies. The highest occupied molecular orbital (HOMO) of the SANC had 65% nonbonding character, whereas the lowest unoccupied molecular orbital (LUMO) was 72% antibonding. The HOMO and LUMO of the SANC arose mostly from Al 3s and 2p atomic orbitals. The theoretically estimated energy gap for this compound was 4.4 eV, which is lower than those for the alumina nanocage (ANC) and nanotube (ANT). The SANC with internal and external diameters of 5.7 and 6.2 A had potential to interact with water molecule from sites Al(I) in the openings of the cage, Al(II) in the internal pore, and Al(III) in the external arms. The relative water adsorption activity of these sites was Al(I) > Al(III) >>> Al(II).The SANC can be introduced as a novel alumina nanostructure with lower stability and higher activity than well-known alumina materials.

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Section: A G (-730)supporting

confidence: 63%

Density functional study of the structure and water adsorption activity of an Al$_{30}$O$_{30}$ star-shaped alumina nanocage

Zamani¹

2016

Turk J Chem

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“…Here, Al ions adopt the A and B cation sites of the spinel structure. Writing the stoichiometry in standard spinel notation, Al 3−δ O 4 with δ = 1 3 , reveals that GAO adopts a defect-spinel structure [20]. Whether these cation vacancies preferably adopt one of the cation sites has been discussed controversially [20][21][22] and strongly affects the potential buildup inside the material.…”

Section: Resultsmentioning

confidence: 99%

“…Writing the stoichiometry in standard spinel notation, Al 3−δ O 4 with δ = 1 3 , reveals that GAO adopts a defect-spinel structure [20]. Whether these cation vacancies preferably adopt one of the cation sites has been discussed controversially [20][21][22] and strongly affects the potential buildup inside the material. From simple electrostatics, taking into account layer spacings and neglecting all other material properties (e.g., the dielectric constant), one obtains the same nominal potential buildup as in LAO for cation vacancies exclusively in tetrahedral sites.…”

Section: Resultsmentioning

confidence: 99%

“…Accordingly, the CBM of STO is found to be almost degenerate with the Fermi level in the bulk and bends below the chemical potential near the interface. Furthermore, due to its large band gap (≈7.9 eV) [20], the CBM of GAO is above that of STO. Accordingly, in contrast to LAO/STO [15,28,30,40], the heterointerface between GAO and STO is found to be of type I.…”

Section: Discussionmentioning

confidence: 99%

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Band bending and alignment at the spinel/perovskiteγ−Al2O3/SrTiO3heterointerface

et al. 2015

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“…The increased binding energy of the plasmon with ion core (localised 5s electrons) provides more intense excitation energy as we observed with a damping Ag layer thickness in the nanometer range. Such growth of the surface plasmon energy at nanostructuring was demonstrated in [24,25] for silver clusters. This definite shift of plasmon peak to higher frequency is also called "blue shift".…”

Section: Experimental Studies Of Plasmon Lossesmentioning

confidence: 99%

Interconnections between Electronic Structure and Optical Properties of Multilayer Nanolaminate TiAlN/Ag and Al2O3/Ag Coatings

et al. 2018

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Abstract:Multilayer nanolaminate TiAlN/Ag and Al 2 O 3 /Ag metal-insulator-metal (MIM) coatings with thicknesses of individual layers from a few to several hundreds of nanometers were fabricated by direct current magnetron sputtering. Their optical transmittance and reflectance spectra were measured for photon energies 1-5 eV (1240-248 nm). The spectra were non-monotonous as their transmission and reflection bands were strongly dependent on the coating architecture. A set of advanced electron spectroscopy methods was used to analyse the electronic structure of the coatings controlling optical properties. Energies of plasmons peaks and the distribution of their intensities are functions of the Ag layers thickness as well as the composition and thickness of the dielectric nanolayers in the MIM nanocomposite. Statistical analysis established the cross-correlations between geometrical parameters of the coatings, transmissions and reflection bands on the optical spectra and parameters of the electronic structure. Particularly, the blue side of the transmittance band is controlled by plasmons while the dielectric band gap determines the transmittance of the red side. The obtained experimental results allowed us to fulfil the computed architectural design of a multilayer Al 2 O 3 /Ag coating with a narrow bandwidth in the visible light region and strong reflection in the infrared and ultraviolet regions.

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Electronic and crystallographic structure of γ-alumina thin films

Cited by 230 publications

References 27 publications

Density functional study of the structure and water adsorption activity of an Al$_{30}$O$_{30}$ star-shaped alumina nanocage

Density functional study of the structure and water adsorption activity of an Al$_{30}$O$_{30}$ star-shaped alumina nanocage

Band bending and alignment at the spinel/perovskiteγ−Al2O3/SrTiO3heterointerface

Interconnections between Electronic Structure and Optical Properties of Multilayer Nanolaminate TiAlN/Ag and Al2O3/Ag Coatings

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