Annealing of ZnS nanocrystals grown by colloidal synthesis

Motlan, Guanghua Zhu, K. Drozdowicz-Tomsia, K. McBean, M. R. Phillips, E. M. Goldys*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

ZnS nanocrystals (NCs) capped with tetramethylammonium (TMAH) were synthesized from ZnCl2 · 2H2O and thiourea using a wet chemical process. Further treatments of the nanocrystals such as aging, and annealing have been conducted to examine the stability of the grown samples. The X-ray diffraction spectra show that the crystal has a zinc blende structure with particle size of about 2 nm. The evidence of nanocrystalline character is also clear in the UV-Vis absorption that shows an excitonic peak at about 236 nm (5.2 eV) arising from band edge transitions. A photoluminescence emission peak centered at about 450 nm (2.7 eV) is attributed to transitions between shallow donors and Zn+ vacancies. Both absorption and photoluminescence spectra show that sample aging does not affect the characteristics of the sample, possibly due to protection by TMAH capping. Annealing at 700 °C and 900 °C results in the red shift of the photoluminescence.

Original languageEnglish
Pages (from-to)1579-1583
Number of pages5
JournalOptical Materials
Volume29
Issue number12
DOIs
Publication statusPublished - Aug 2007

Keywords

  • ZnS
  • nanocrystals
  • annealing
  • photoluminescence emission

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