Spectroscopic ellipsometry studies of optical properties of TlIn(S0.25Se0.75)2 crystal

Guler I., Isik M., HASANLI N.

Applied Physics A: Materials Science and Processing, vol.129, no.6, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 129 Issue: 6
  • Publication Date: 2023
  • Doi Number: 10.1007/s00339-023-06729-4
  • Journal Name: Applied Physics A: Materials Science and Processing
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex
  • Keywords: 2D materials, Bandgap energy, Ellipsometry, Optical constants, TlInS2, TlInSe2
  • Middle East Technical University Affiliated: Yes

Abstract

The optical properties of TlIn(S0.25Se0.75)2 crystals were studied by ellipsometry measurements. X-ray diffraction pattern presented well-defined peaks associated with monoclinic structure. Energy dependent graphs of various linear optical parameters of the crystal were presented in the 1.25–4.50 eV range. The band gap and Urbach energies of the compound were found as 1.96 and 0.68 eV, respectively, from the analyses of the absorption coefficient. Refractive index spectrum was analyzed considering the single-effective-oscillator model to get oscillator and dispersion energies, zero and high frequency dielectric constants, plasma frequency. Moreover, the nonlinear refractive index, first-order and third-order nonlinear susceptibilities of TlIn(S0.25Se0.75)2 crystal were revealed in the present paper.