Preparation and study of the annealing temperature, optical and structural properties of ZnTe0.8Se0.2 thin films

The optical and structural characteristics of ZnTe1-0.2Se0.2 (ZTS) semiconductors are examined using the thermal evaporation process. We analyze 500 nm thickness films and explore the effects of annealing temperatures ranging from RT to 373 and 473K. The optical properties of films were assessed using a wavelength range (400-1000nm). ZnTe0.8Se0.2 semiconductors exhibit direct band gaps of 1.86, 1.81, and 1.78eV, respectively. Included in the computed optical constant are the refractive index and extinction coefficient. XRD and AFM studies demonstrate that films are polycrystalline with a superior stoichiometric composition. One of the preferred orientations of the polycrystalline phase is along the (111) direction. Also, increasing the annealing temperature led to an increase in the crystal and grain size, which contributes to improving the structural properties of the films. Additionally, the energy gap of the annealed films is close to the green color in the visible spectrum, making them suitable for optoelectronic applications.