Study of Structural and Optical Properties of Tl 2 Te 3 Thermally Evaporation Thin Films

The present work concerns the structure and optical studies of Tl 2 Te 3 thin films prepared by the thermal evaporation technique at room temperature under a vacuum of 10 −5 Pa. X-ray diffraction proved the polycrystalline nature of all films. The crystallite size was calculated, and their values varied from 18.21 to 12.6 nm for different thicknesses. The optical properties of the Tl 2 Te 3 thin films were measured in the wavelength range of 300–1200 nm. The results revealed that the films had a direct energy gap. The direct energy gap varied from 1.01 to 0.8 eV with film thicknesses. Other linear and nonlinear optical constants such as the refractive index, absorption index, dielectric constant, and dielectric relaxation time, were determined.