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A time-resolved cathodo- and photoluminescence study of nanostructural modifications of Al2O3 (powders and ceramics) excited by heavy-current electron beams, as well as by pulsed synchrotron radiation, is reported. It was found that Al2O3 nanopowders probed before and after Fe+ ion irradiation have the same phase composition (the γ-phase/δ-phase ratio is equal to 1), an average grain size equal to ∼17 nm, and practically the same set of broad cathodoluminescence (CL) bands peaking at 2.4, 3.2, and 3.8 eV. It was established that Al 2O3 nanopowders exhibit fast photoluminescence (PL) (a band at 3.2 eV), whose decay kinetics is described by two exponential stages (τ1 = 0.5 ns, τ2 = 5.5 ns). Three bands, at 5.24, 6.13, and 7.44 eV, were isolated in the excitation spectrum of the fast PL. Two alternate models of PL centers were considered, according to which the 3.2-eV luminescence either originates from radiative relaxation of the P- centers (anion-cation vacancy pairs) or is due to the formation of surface analogs of the F+ center (FS+-type centers). In addition to the fast luminescence, nano-Al2O3 was found to produce slow luminescence in the form of a broad band peaking at 3.5 eV. The excitation spectrum of the 3.5-eV luminescence obtained at T = 13 K exhibits two doublet bands with maxima at 7.8 and 8.3 eV. An analysis of the luminescent properties of nanostructural and single-crystal Al2O3 suggests that the slow luminescence of nanopowders at 3.5 eV is due to radiative annihilation of excitons localized near structural defects.
| Язык оригинала | Английский |
|---|---|
| Страницы (с-по) | 733-737 |
| Число страниц | 5 |
| Журнал | Physics of the Solid State |
| Том | 47 |
| Номер выпуска | 4 |
| DOI | |
| Состояние | Опубликовано - 21 июл 2005 |
Отпечаток
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
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Electronic excitations and defects in nanostructural Al2O 3. / Gorbunov, S. V.; Zatsepin, A. F.; Pustovarov, V. A.; Cholakh, S. O.; Yakovlev, V. Yu.
В: Physics of the Solid State, Том 47, № 4, 21.07.2005, стр. 733-737.Результат исследований: Материалы для журнала › Статья
}
TY - JOUR
T1 - Electronic excitations and defects in nanostructural Al2O 3
AU - Gorbunov, S. V.
AU - Zatsepin, A. F.
AU - Pustovarov, V. A.
AU - Cholakh, S. O.
AU - Yakovlev, V. Yu
PY - 2005/7/21
Y1 - 2005/7/21
N2 - A time-resolved cathodo- and photoluminescence study of nanostructural modifications of Al2O3 (powders and ceramics) excited by heavy-current electron beams, as well as by pulsed synchrotron radiation, is reported. It was found that Al2O3 nanopowders probed before and after Fe+ ion irradiation have the same phase composition (the γ-phase/δ-phase ratio is equal to 1), an average grain size equal to ∼17 nm, and practically the same set of broad cathodoluminescence (CL) bands peaking at 2.4, 3.2, and 3.8 eV. It was established that Al 2O3 nanopowders exhibit fast photoluminescence (PL) (a band at 3.2 eV), whose decay kinetics is described by two exponential stages (τ1 = 0.5 ns, τ2 = 5.5 ns). Three bands, at 5.24, 6.13, and 7.44 eV, were isolated in the excitation spectrum of the fast PL. Two alternate models of PL centers were considered, according to which the 3.2-eV luminescence either originates from radiative relaxation of the P- centers (anion-cation vacancy pairs) or is due to the formation of surface analogs of the F+ center (FS+-type centers). In addition to the fast luminescence, nano-Al2O3 was found to produce slow luminescence in the form of a broad band peaking at 3.5 eV. The excitation spectrum of the 3.5-eV luminescence obtained at T = 13 K exhibits two doublet bands with maxima at 7.8 and 8.3 eV. An analysis of the luminescent properties of nanostructural and single-crystal Al2O3 suggests that the slow luminescence of nanopowders at 3.5 eV is due to radiative annihilation of excitons localized near structural defects.
AB - A time-resolved cathodo- and photoluminescence study of nanostructural modifications of Al2O3 (powders and ceramics) excited by heavy-current electron beams, as well as by pulsed synchrotron radiation, is reported. It was found that Al2O3 nanopowders probed before and after Fe+ ion irradiation have the same phase composition (the γ-phase/δ-phase ratio is equal to 1), an average grain size equal to ∼17 nm, and practically the same set of broad cathodoluminescence (CL) bands peaking at 2.4, 3.2, and 3.8 eV. It was established that Al 2O3 nanopowders exhibit fast photoluminescence (PL) (a band at 3.2 eV), whose decay kinetics is described by two exponential stages (τ1 = 0.5 ns, τ2 = 5.5 ns). Three bands, at 5.24, 6.13, and 7.44 eV, were isolated in the excitation spectrum of the fast PL. Two alternate models of PL centers were considered, according to which the 3.2-eV luminescence either originates from radiative relaxation of the P- centers (anion-cation vacancy pairs) or is due to the formation of surface analogs of the F+ center (FS+-type centers). In addition to the fast luminescence, nano-Al2O3 was found to produce slow luminescence in the form of a broad band peaking at 3.5 eV. The excitation spectrum of the 3.5-eV luminescence obtained at T = 13 K exhibits two doublet bands with maxima at 7.8 and 8.3 eV. An analysis of the luminescent properties of nanostructural and single-crystal Al2O3 suggests that the slow luminescence of nanopowders at 3.5 eV is due to radiative annihilation of excitons localized near structural defects.
UR - http://www.scopus.com/inward/record.url?scp=21844446873&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=21844446873&partnerID=8YFLogxK
U2 - 10.1134/1.1913989
DO - 10.1134/1.1913989
M3 - Article
AN - SCOPUS:21844446873
VL - 47
SP - 733
EP - 737
JO - Physics of the Solid State
JF - Physics of the Solid State
SN - 1063-7834
IS - 4
ER -