Luminescence centers in Al2O3

Kristianpoller, N.; Rehavy, A.

doi:10.1016/0022-2313(79)90112-1

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…To test where this peak originates from, we also measured the cathodoluminescence spectra of nondoped Al 2 O 3 , SiO 2 , and Zeolite A (approximate composition: NaAlSiO 4 ), which showed this peak both for Zeolite A and Al 2 O 3 (Figure S1). Thus, in line with previous reports on the luminescence of α-Al 2 O 3 , we assign this band to an F + center, − i.e., an oxygen vacancy occupied with one electron, in the vicinity of Al 3+ . In this same band, one can also observe small glitches at 359, 393, and 432 nm, which can be assigned to the transitions of small amounts of N 2 and Ar present in the measurement chamber .…”

Section: Resultssupporting

confidence: 90%

Hackmanite—The Natural Glow-in-the-Dark Material

et al. 2020

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“Glow-in-the-dark” materials are known to practically everyone who has ever traveled by airplane or cruise ship, since they are commonly used for self-lit emergency exit signs. The green afterglow, persistent luminescence (PeL), is obtained from divalent europium doped to a synthetic strontium aluminate, but there are also some natural minerals capable of afterglow. One such mineral is hackmanite, the afterglow of which has never been thoroughly investigated, even if its synthetic versions can compete with some of the best commercially available synthetic PeL materials. Here we combine experimental and computational data to show that the white PeL of natural hackmanite is generated and controlled by a very delicate interplay between the natural impurities present. The results obtained shed light on the PeL phenomenon itself thus giving insight into improving the performance of synthetic materials.

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Section: Resultssupporting

confidence: 90%

Hackmanite—The Natural Glow-in-the-Dark Material

et al. 2020

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“…impurities doped into the single crystal Al 2 O 3 . Further, a strong narrow PL band near the 696-nm due to Cr 3? impurities was observed at 698 nm in the nominally pure synthetic sapphire [32] and at *694 nm in the ceramic Al 2 O 3 prepared from the mixture of Al 2 O 3 and Cr 2 O 3 powders [33]. The intensity and the position of the narrow band changed depending on the Cr 3?…”

Section: Discussionmentioning

confidence: 91%

Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner

Nakayama

2009

Tribol Lett

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In this work, the characteristics of triboplasma have been investigated from the point of view of how the kinds of the stationary partner influence the photon energy and the plasma distribution. The energy spectrum and twodimensional images of the emitted photons were measured during the sliding of a diamond pin with a tip radius of 1.5 and 3 mm on the three kinds of disk made of Al 2 O 3 , MgO, and SiO 2 in dry sliding in air. The results showed that all the three kinds of solid tested had narrow bands of airdischarge plasma in the ultraviolet region, demonstrating that the triboplasma generation does not depend on the kinds of insulating solids. Triboplasma was distributed having a ring with one or two tails in all the three kinds of solid Al 2 O 3 , MgO, and SiO 2 . The mechanisms of UV, visible, and IR photon emissions are discussed. The UV photons are emitted from the ionized plasma gas produced by discharging of air, while the visible photons are emitted from the defect and impurity centers excited by the triboplasma-photons, triboplasma-electrons, and frictional temperature rise together with the photons from the plasma itself. A 696-nm narrow band appeared only with Al 2 O 3 , and it was attributed to the Cr 3? ions excited by the UV photons and electrons from the triboplasma. The IR photons should be emitted from the sliding contact by the thermal emissions consisting of thermoluminescence and blackbody radiation, as well as from the triboplasma. The visible photon emission was strongest at the pair points facing across the frictional track in Al 2 O 3 and MgO. To explain the photon emission at the pair points, a new model has been proposed, in which the visible photons are emitted from the surface defect and/or impurity centers excited by the back electrons accelerated with the inverse electric field caused by the negatively charged patches produced by the electron bombardment to the diamond surface. The negative charges on the frictional track repelled the back electrons, so that the back-electrons attack just outside the frictional track.

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“…The MOS capacitors were subjected to forming gas annealing at 430 °C for 30 minutes before measurement. UV or X-ray irradiation does not cause ionic lattice displacements in the regular Al2O3 lattice, but displacements can occur in the vicinity of existing vacancies (6). Relatively high densities of oxygen vacancies can occur in alumina, in particular the • and •• color centers, which are O vacancies with one or two electrons, respectively.…”

Section: Resultsmentioning

confidence: 99%

(Invited) Vacuum Ultraviolet Photochemical Atomic Layer Deposition of Alumina and Titania Films

et al. 2015

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Conventional atomic layer deposition (ALD) is a thermo-chemical process where co-reagents are sequentially pulsed in cycles onto a heated substrate. As an alternative to substrate heating, various forms of other "non-thermal" ALD processes are being investigated. Herein, the photochemical atomic layer deposition of Al2O3 and TiO2 thin films at 60°C is reported using a shuttered vacuum ultraviolet light source to excite molecular oxygen as a coreagent with the metal precursors. The growth mechanisms using trimethyl aluminium and titanium tetraisopropoxide precursors, are investigated using in-situ quartz crystal microbalance and postdeposition ellipsometric measurements. The photochemical ALD Al2O3 films exhibit different capacitance equivalent thicknesses for irradiated and masked regions respectively, even after postdeposition annealing. The photochemical ALD titania films are amorphous and when incorporated into Pt / TiO2 / Pt metalinsulator-metal structures, the titania exhibits a resistive switching behavior.

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Luminescence centers in Al2O3

Cited by 8 publications

References 6 publications

Hackmanite—The Natural Glow-in-the-Dark Material

Hackmanite—The Natural Glow-in-the-Dark Material

Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner

(Invited) Vacuum Ultraviolet Photochemical Atomic Layer Deposition of Alumina and Titania Films

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