Optical absorption and reflection studies of Tl4InGa3S8 layered single crystals

Goksen K., Gasanly N., Ozkan H.

ACTA PHYSICA POLONICA A, cilt.112, sa.1, ss.93-100, 2007 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 112 Sayı: 1
  • Basım Tarihi: 2007
  • Doi Numarası: 10.12693/aphyspola.112.93
  • Dergi Adı: ACTA PHYSICA POLONICA A
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.93-100
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

The optical properties of Tl4InGa3S8 layered single crystals have been studied by means of transmission and reflection measurements in the wavelength region between 400 and 1100 nm. The analysis of the room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 2.40 and 2.61 eV, respectively. Transmission measurements carried out in the temperature range of 10-300 K revealed the rate of change of the indirect band gap with temperature as gamma = -6.0 x 10(-4) eV/K. The absolute zero value of the band gap energy was obtained as E-gi(0) = 2.52 eV. The dispersion of the refractive index is discussed in terms of the Wemple-DiDomenico single-effective-oscillator model. The refractive index dispersion parameters: oscillator energy, dispersion energy, oscillator strength, and zero-frequency refractive index were found to be 5.07 eV, 26.67 eV, 8.82 x 10(13) m(-2), and 2.50, respectively.