Crystal data and indirect optical transitions in Tl2InGaSe4 crystals

QASRAWI A. F. H., Gasanly N.

MATERIALS RESEARCH BULLETIN, vol.43, no.6, pp.1497-1501, 2008 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 6
  • Publication Date: 2008
  • Doi Number: 10.1016/j.materresbull.2007.06.025
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1497-1501
  • Middle East Technical University Affiliated: Yes


The room temperature crystal data and the optical properties of the Bridgman method grown Tl2InGaSe4 crystals are reported and discussed. The X-ray diffraction technique has revealed that Tl2InGaSe4 is a single phase crystal of monoclinic structure. The unit cell lattice parameters, which were recalculated from the X-ray data, are found to be a = 0.77244 nm, b = 0.64945 nm, c = 0.92205 nm and beta = 95.03 degrees. The temperature dependence of the optical band gap of Tl2InGaSe4 single crystal in the temperature region of 290-500 K has also been investigated. The absorption coefficient was calculated from the transmittance and reflectance data in the incident photon energy range of 1.60-2.10 eV. The absorption edge is observed to shift toward lower energy values as temperature increases. The fundamental absorption edge corresponds to indirect allowed transition energy gap of 1.86 eV that exhibited a temperature coefficient gamma = -3.53 x 10(-4) eV/K. (C) 2007 Elsevier Ltd. All rights reserved.