Structural analysis, dielectric relaxation, and AC electrical conductivity in TlInSe${}_2$ thin films as a function of temperature and frequency

Thallium indium di-selenium (TlInSe${}_2$) is one of the most promising chalcogenide materials having a layered crystalline structure that has been nominated in different fields of industry. In our work, a film of TlInSe${}_2$ has been fabricated using a coating unit. The morphology properties of TlInSe${}_2$ have been investigated by atomic force microscopy (AFM). The Raman spectroscopy proved that there are identical spectra between the powder and the film, and they agreed with what was previously reported for the TlInSe${}_2$ crystal. By AFM, it was found that the grain sizes and the roughness of TlInSe${}_2$ film are 100 and 6.49 nm, respectively. The real (ε${}_1$) and imaginary (ε${}_2$) parts of complex dielectric permittivity and AC conductivity were measured in the frequency range of 42 Hz-5 MHz with a variation of temperature in the range from 303 to 443 K. The estimated values of ΔE${}_M$ and τ${}_o$ were found to be 0.321 eV and 2.28 × 10${}^{-10}$ s, respectively. The electrical conductivity of TlInSe${}_2$ thin film increased by about 40% as the temperature increased from 303 to 443 K. On the contrary, the AC activation energy has decreased rapidly by about 54%.