Polarization mechanisms of TlSbS2 thin films

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Yakut Ş., Ulutaş D., Bozoğlu Parto D., Ulutaş H. K.

JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, vol.25, no.5-6, pp.294-301, 2023 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 25 Issue: 5-6
  • Publication Date: 2023
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex
  • Page Numbers: pp.294-301
  • Istanbul University Affiliated: Yes


TlSbS2 is a material having good photovoltaic and thermoelectric properties in bulk form. Electrical characteristics are important to analyze such properties as photovoltaic and thermoelectric. Improvements in industrial and technological applications required materials having low size. Thus, it is important to analyze this material in nano-size dimensions. For this reason, TlSbS2 was investigated in thin film form. To make the detailed characterization of dielectric properties enabled, the dielectric investigation of TlSbS2 thin films was operated depending on frequency, temperature, and film thickness. In this study, TlSbS2 thin films are produced by the deposition of TlSbS2 bulk samples by thermal evaporation on glass substrates. The thicknesses of the films are between 49 and 619 nm. The dielectric properties and ac conductivity of the TlSbS2 thin films at a temperature range 293-373 K are measured over a frequency range between 20 Hz and 1kHz. The dielectric constant increases with increasing thickness starting from almost 10 to almost 30. Two polarization mechanisms are observed. One of them can be related to the interfacial polarization of partially free charge carriers including atom groups constructed from combinations of Tl, Sb, and S or individual atoms of Tl, Sb, and S. The polarization of bonds between Tl-S and Sb-S inside local crystal states can be attributed to orientational (dipolar) polarization. Activation energies of the polarization mechanisms are determined. In addition to dielectric spectroscopy measurements, XRD analysis results show that the TlSbS2 bulk samples (raw samples used for the deposition of thin films) are in crystalline form. However, TlSbS2 thin films deposited from TlSbS2 bulk samples by thermal evaporatio