Optical constants of wurtzite ZnS thin films determined by spectroscopic ellipsometry

H. C. Ong*, R. P.H. Chang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

167 Scopus citations

Abstract

The complex dielectric functions of wurtzite ZnS thin films grown on (0001) Al2O3 have been determined by using spectroscopic ellipsometry over the spectral range of 1.33-4.7 eV. Below the band gap, the refractive index n is found to follow the first-order Sellmeir dispersion relationship n2(λ)=1+2.22λ2/(λ 2-0.0382). Strong and well-defined free excitonic features located above the band edge are clearly observed at room temperature. The intrinsic optical parameters of wurtzite ZnS such as band gaps and excitonic binding energies have been determined by fitting the absorption spectrum using a modified Elliott expression together with Lorentizan broadening. Both parameters are found to be larger than their zinc blende counterparts.

Original languageEnglish (US)
Pages (from-to)3612-3614
Number of pages3
JournalApplied Physics Letters
Volume79
Issue number22
DOIs
StatePublished - Nov 26 2001

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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