Hole-induced exoelectron emission and luminescence of corundum doped with Mg

Кортов, В. С.; Bessonova, T. S.; Akselrod, M.S.; Milman, I. I.

doi:10.1002/pssa.2210870227

Cited by 36 publications

(19 citation statements)

References 25 publications

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“…There is also evidence for another type of defect which is originated by the removal of cations from the oxide. [55][56][57][58][59][60] Nevertheless, oxygen vacancies are thought to be the most stable defects with characteristic optical absorption spectra showing an absorption band at 6.05 eV, which was found to be formed by two peaks at 5.91 and 6.22 eV and, again as in the case of MgO, are attributed to F ϩ and F centers in ␣-Al 2 O 3 . 56 The number of electrons present at these point defects and their spatial extent affects the electronic properties of adsorbed species and consequently they may be responsible for the catalytic activity of the support.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of bulk and surface oxygen and aluminum vacancies inα−Al2O3

2004

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The formation energy, geometry, and electronic structure of isolated oxygen and aluminum vacancies in bulk and on the ͑0001͒ surface of corundum (␣-Al 2 O 3 ) have been investigated by means of periodic calculations in the framework of density functional theory within the generalized gradient approximation and large supercells. The energy cost to form an oxygen vacancy in the bulk is estimated to be of the order of 10 eV, whereas that corresponding to the formation of Al vacancies is found to be at least a 30% larger. The relaxation of the material is rather small for both defects. The removal of an oxygen atom in bulk ␣-Al 2 O 3 is accompanied by the appearance of an impurity level in the gap, which is a strong indication of electron localization. This has been further confirmed by integration of the density of states in the energy interval corresponding to the impurity level and by several other theoretical analyses. For the ␣-Al 2 O 3 (0001) surface, the formation of oxygen and aluminum vacancies exhibits many similarities with the bulk; the energy cost to form Al vacancies is much larger than for O vacancies and, in both cases, it is accompanied by rather small atomic displacements. However, there are also significant differences between bulk and surface oxygen and aluminum vacancies. Thus the formation energy of one of these point defects in the surface is rather smaller as expected and, more importantly, the degree of electronic delocalization is also larger.

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Section: Introductionmentioning

confidence: 99%

Theoretical study of bulk and surface oxygen and aluminum vacancies inα−Al2O3

2004

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“…The nature of such centers as well as their electronic structure including the F + centers (i.e. one electron trapped at oxygen vacancy), has been investigated [2][3][4]. Here it was shown that such centers can be thermally ionized and when present in sufficient concentration, can impart dosimetric utility to alumina.…”

Section: Introductionmentioning

confidence: 95%

In-Vacuo thermal processing of α-Al2O3 single crystals in boron ambience and its implication on TL & OSL response

Soni

Muthe

Kulkarni

et al. 2010

Journal of Luminescence

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“…It was found that the sizes of crystals in the synthesized anion defective ceramics did not exceed 150-200 nm. Furthermore, it is known that magnesium ions encourage the formation of additional centers, includ ing oxygen vacancies, in aluminum oxide [15].…”

Section: Objects Of Investigation and Experimental Techniquementioning

confidence: 99%

Luminescent and dosimetric properties of nanostructured ceramics based on aluminum oxide

et al. 2013

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Abstract-The main features of thermoluminescence (TL) of nanostructured ceramics based on anion defective aluminum oxide have been investigated. The kinetic parameters of the TL dosimetric peak at 475 K have been determined. The possibility of using nanostructured ceramics for beta radiation dosimetry of high doses (up to 1 kGy) with thermoluminescence of deep traps has been justified. It has been found that the light sum of the dosimetric peak decreases with an increase in the heating rate due to the temperature quenching of the luminescence. The obtained results have confirmed that the mechanism of TL quenching in anion defective aluminum oxide is associated with the temperature dependence of the probability of the capture in deep traps, which can be caused by thermal ionization of excited states of F centers.

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Hole-induced exoelectron emission and luminescence of corundum doped with Mg

Cited by 36 publications

References 25 publications

Theoretical study of bulk and surface oxygen and aluminum vacancies inα−Al2O3

Theoretical study of bulk and surface oxygen and aluminum vacancies inα−Al2O3

In-Vacuo thermal processing of α-Al2O3 single crystals in boron ambience and its implication on TL & OSL response

Luminescent and dosimetric properties of nanostructured ceramics based on aluminum oxide

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