The influence of frequency and temperature on the AC-conductivity in $$\text {TlInTe}_2$$ semiconductor single crystal
Authors: Fangary Mohamed M. , Ahmed Muhammad A. O. 
Published: February 2025

Abstract
A special design, based on the Bridgman technique, was used in our laboratory for preparing single crystals of
$$\text {TlInTe}_2$$
. The structure of
$$\text {TlInTe}_2$$
in powder form was examined using X-ray diffraction.
$$\text {TlInTe}_2$$
at room temperature was found to be a tetragonal system with lattice parameters of
$$a = 8.494$$
Å and
$$c = 7.181$$
Å. The structural parameters, such as crystallite size D, micro strain
$$\epsilon$$
, dislocation density
$$\delta$$
, and unit cell parameters were determined from XRD spectra. Thermo gravimetric analysis (TGA) was employed to study the thermal behavior of
$$\text {TlInTe}_2$$
, showcasing its significance in solid state physics. The TGA curve of
$$\text {TlInTe}_2$$
exhibited distinct weight loss events corresponding to thermal decomposition processes. The frequency and temperature dependence of Ac-conductivity in a
$$\text {TlInTe}_2$$
single crystal was studied by assessing the permittivity (
$$\epsilon _r$$
) and dielectric loss (
$$\tan \delta$$
) over a broad frequency range. The dependence of AC conductivity and dielectric properties on the frequency and temperature for
$$\text {TlInTe}_2$$
in pellet form obtained from
$$\text {TlInTe}_2$$
single crystal were studied in the frequency range of (40 Hz–3 MHz) and temperature range of
$$(290{-}395)^{\circ }$$
K. The AC conductivity of the
$$\text {TlInTe}_2$$
was found to obey the power law, i.e.,
$$\sigma _{ac} (\omega ) = A \omega ^s$$
. AC conductivity of
$$\text {TlInTe}_2$$
was dominated by the correlated barrier hopping (CBH) model. The obtained activation energy values of the AC conductivity have confirmed that the hopping conduction is the dominant one. A decrease in these values has noticed with the increase in frequency. The density of localized states
$$N (E_F)$$
close to Fermi level for
$$\text {TlInTe}_2$$
was obtained in the range of
$$(1.02{-}2.8 \times 10^{19}\ \text {eV}^{-1}$$
cm
$$^{-3}$$
) for various temperatures and frequency. The frequencies corresponding to maxima of the imaginary electric modulus at different temperatures were found to satisfy an Arrhenius law with activation energy
$$E_R$$
of 0.32 eV. A decrease in the relaxation time
$$\tau$$
was observed with the increase in temperature. The average hopping distance R and the average time of charge carrier hoping between localized states t were found in the range of 6.10–11.95 nm and
$$2 \times 10^{-7} {-} 2.4 \times 10^{-2}$$
s respectively, for the investigated range of frequency and the value of the binding energy
$$W_m$$
was 0.52 eV. We report on the preparation, characterization, and analysis of
$$\text {TlInTe}_2$$
semiconductor single crystals, focusing on the influence of frequency and temperature on AC conductivity. Utilizing X-ray diffraction, thermo gravimetric analysis, and dielectric property measurements, we delineate the material’s structural and electrical properties. Complementing our experimental findings, Machine Learning (ML) models, including Random Forest and Gradient Boosting, were employed to predict AC conductivity, revealing significant predictors and corroborating the experimental insights with high accuracy. This interdisciplinary approach enhances our understanding of
$$\text {TlInTe}_2$$
’s properties and demonstrates the potential of ML in materials science research.