Electronic excitations and defects in nanostructural Al2O3 / Gorbunov SV,Zatsepin AF,Pustovarov VA,Cholakh SO,Yakovlev VY // PHYSICS OF THE SOLID STATE. - 2005. - V. 47, l. 4. - P. 733-737.

ISSN/EISSN:

1063-7834 / нет данных

Type:

Article

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 gamma-phase/delta-phase ratio is equal to 1), an average grain size equal to similar 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 Al2O3 nanopowders exhibit fast photoluminescence (PL) (a band at 3.2 eV), whose decay kinetics is described by two exponential stages (tau(1) = 0.5 ns, tau(2) = 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 (F-S(+)-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. (C) 2005 Pleiades Publishing, Inc.

Author keywords:

LUMINESCENCE; CRYSTALLINE; EMISSION

DOI:

10.1134/1.1913989

Web of Science ID:

ISI:000228634100024

Соавторы в МНС:

Другие поля

Поле	Значение
Publisher	AMER INST PHYSICS
Address	CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA
Language	English
Keywords-Plus	LUMINESCENCE; CRYSTALLINE; EMISSION
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
Author-Email	zats@dpt.ustu.ru
ResearcherID-Numbers	Zatsepin, Anatoly/L-7335-2016 Cholakh, Seif/M-8221-2016
ORCID-Numbers	Zatsepin, Anatoly/0000-0001-9539-2403 Cholakh, Seif/0000-0002-9313-6614
Number-of-Cited-References	9
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	11
Journal-ISO	Phys. Solid State
Doc-Delivery-Number	919RA