The role of surface and deep-level defects on the emission of tin oxide quantum dots

Vinod Kumar, Vijay Kumar, S. Som, J. H. Neethling, Ezra Olivier, O. M. Ntwaeaborwa, H. C. Swart

Research output: Contribution to journalArticlepeer-review

117 Citations (Scopus)

Abstract

This paper reports on the role of surface and deep-level defects on the blue emission of tin oxide quantum dots (SnO2QDs) synthesized by the solution-combustion method at different combustion temperatures. X-ray diffraction studies showed the formation of a single rutile SnO2 phase with a tetragonal lattice structure. High resolution transmission electron microscopy studies revealed an increase in the average dot size from 2.2 to 3.6 nm with an increase of the combustion temperature from 350 to 550 °C. A decrease in the band gap value from 3.37 to 2.76 eV was observed with the increase in dot size due to the quantum confinement effect. The photoluminescence emission was measured for excitation at 325 nm and it showed a broad blue emission band for all the combustion temperatures studied. This was due to the creation of various oxygen and tin vacancies/defects as confirmed by x-ray photoelectron spectroscopy data. The origin of the blue emission in the SnO2 QDs is discussed with the help of an energy band diagram.

Original languageEnglish
Article number135701
JournalNanotechnology
Volume25
Issue number13
DOIs
Publication statusPublished - 4 Apr 2014
Externally publishedYes

Keywords

  • blue emission
  • surface defect and deeplevel defect

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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