Luminescence characterization and electron beam induced chemical changes on the surface of ZnAl 2 O 4 :Mn nanocrystalline phosphor

Shreyas S. Pitale, Vinay Kumar, I. M. Nagpure, O. M. Ntwaeaborwa, H. C. Swart

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Luminescence characteristics and surface chemical changes of nanocrystalline Mn 2+ doped ZnAl 2 O 4 powder phosphors are presented. Stable green cathodoluminescence (CL) or photoluminescence (PL) with a maximum at ∼512 nm was observed when the powders were irradiated with a beam of high energy electrons or a monochromatic xenon lamp at room temperature. This green emission can be attributed to the 4 T 16 A 1 transitions of the Mn 2+ ion. Deconvoluted CL spectra resulted in two additional emission peaks at 539 and 573 nm that may be attributed to vibronic sideband and Mn 4+ emission, respectively. The luminescence decay of the Mn 2+ 512 nm emission under 457 nm excitation is single exponential with a lifetime of 5.20 ± 0.11 ms. Chemical changes on the surface of the ZnAl 2 O 4 :Mn 2+ phosphor during prolonged electron beam exposure were monitored using Auger electron spectroscopy. The X-ray photoelectron spectroscopy (XPS) was used to determine the chemical composition of the possible compounds formed on the surface as a result of the prolonged electron beam exposure. The XPS data suggest that the thermodynamically stable Al 2 O 3 layer was formed on the surface and is possibly contributing to the CL stability of ZnAl 2 O 4 :Mn phosphor.

Original languageEnglish
Pages (from-to)3298-3306
Number of pages9
JournalApplied Surface Science
Volume257
Issue number8
DOIs
Publication statusPublished - 1 Feb 2011
Externally publishedYes

Keywords

  • Auger electron spectroscopy
  • Cathodoluminescence
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • General Physics and Astronomy
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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