Electronic excitations and defects in nanostructural Al2O 3

S. V. Gorbunov, A. F. Zatsepin, V. A. Pustovarov, S. O. Cholakh, V. Yu Yakovlev

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish
Pages (from-to)733-737
Number of pages5
JournalPhysics of the Solid State
Volume47
Issue number4
DOIs
Publication statusPublished - 21 Jul 2005

Fingerprint

Luminescence
luminescence
Photoluminescence
Defects
defects
photoluminescence
electronics
excitation
Cathodoluminescence
Ion bombardment
cathodoluminescence
color centers
Synchrotron radiation
ion irradiation
Phase composition
Excitons
Powders
Vacancies
Anions
Cations

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Gorbunov, S. V., Zatsepin, A. F., Pustovarov, V. A., Cholakh, S. O., & Yakovlev, V. Y. (2005). Electronic excitations and defects in nanostructural Al2O 3. Physics of the Solid State, 47(4), 733-737. https://doi.org/10.1134/1.1913989

Electronic excitations and defects in nanostructural Al2O 3. / Gorbunov, S. V.; Zatsepin, A. F.; Pustovarov, V. A.; Cholakh, S. O.; Yakovlev, V. Yu.

In: Physics of the Solid State, Vol. 47, No. 4, 21.07.2005, p. 733-737.

Research output: Contribution to journalArticle

Gorbunov, SV, Zatsepin, AF, Pustovarov, VA, Cholakh, SO & Yakovlev, VY 2005, 'Electronic excitations and defects in nanostructural Al2O 3', Physics of the Solid State, vol. 47, no. 4, pp. 733-737. https://doi.org/10.1134/1.1913989
Gorbunov, S. V. ; Zatsepin, A. F. ; Pustovarov, V. A. ; Cholakh, S. O. ; Yakovlev, V. Yu. / Electronic excitations and defects in nanostructural Al2O 3. In: Physics of the Solid State. 2005 ; Vol. 47, No. 4. pp. 733-737.
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