Particle size reduction of thallium indium disulphide nanostructured thin films due to post annealing

Chalcogenide semiconductors are widely used, due to their versatile structural, optical and electrical properties. They are used in image sensors, energy conversion, non-volatile memory, and waveguides applications. Due to these versatilities in the properties, nanostructured thin films of TlInS2 are successfully prepared by thermal evaporation. The average particle size changes due to thermal treatment are examined by X-ray diffraction (XRD), and transmission electron microscope (TEM). A sharp reduction in the average particle size of the pristine nanostructured films is reported upon annealing processes at 423 K and 523 K. Besides, thermal treatment temperatures induce changes in the dispersion parameters viz oscillator energy, dispersion energy, high-frequency dielectric constant and dielectric constant. Of these, only the oscillator energy decreases with the annealing temperatures while all the other parameters increase. Moreover, the non-linear optical calculations have revealed that the nanostructured TlInS2 films exhibit high third-order nonlinear optical susceptibility of order 10⁻¹¹ esu and strong nonlinear refractive index of order 10⁻¹⁰ esu.