Temperature dependent optical constants of amorphous Ge2Sb 2Te5 thin films

E. M. Vinod, Ramakanta Naik, A. P.A. Faiyas, R. Ganesan, K. S. Sangunni

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24 Citations (Scopus)


This study focuses on the temperature dependent optical band gap changes in the amorphous Ge2Sb2Te5 (GST) films. The behavior of the amorphous GST thin films at low temperatures has been studied. The band gap increment of around 0.2 eV is observed at low temperature (4.2 K) compared to room temperature (300 K). The band gap changes associated with the temperature are completely reversible. The other optical parameters like Urbach energy and Tauc parameter (B1/2) are studied for different temperatures and discussed. The observed changes in optical band gap (E g) are fitting to Fan's one phonon approximation. Phonon energy (Latin small letter h with strokeω) corresponding to a frequency of 3.59 THz is derived from Fan's approximation, which is close to the reported value of 3.66 THz.

Original languageEnglish
Pages (from-to)2172-2174
Number of pages3
JournalJournal of Non-Crystalline Solids
Issue number41-42
Publication statusPublished - 1 Sep 2010



  • Chalcogenides (ChG)
  • GeSbTe (GST)
  • Optical band gap
  • Urbach energy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

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