An Effect of Al on the Properties of ZnIn₂Se₄ Thin Film

Abstract

Zinc-indium-selenide ZnIn2Se4 (ZIS) ternary chalcopyrite thin film on glass with a 500 nm thickness was fabricated by using the thermal evaporation system with a pressure of approximately 2.5×10−5 mbar and a deposition rate of 12 Å/s. The effect of aluminum (Al) doping with 0.02 and 0.04 ratios on the structural and optical properties of film was examined. The utilization of X-ray diffraction (XRD) was employed to showcase the influence of aluminum doping on structural properties. XRD shows that thin ZIS-pure, Al-doped films at RT are polycrystalline with tetragonal structure and preferred (112) orientation. Where the degree of crystallinity is raised. The effect of Al content on surface roughness and average diameter was studied by atomic force microscopy (AFM), which showed that both surface roughness and average diameter increased with an increasing Al ratio until they reached their maximum values of 12.93 nm and 61.56 nm, respectively. Optical characteristics of ZIS thin film and the impact of aluminum on optical parameters have been investigated, and it was found that the optical energy ( E g opt ), absorption coefficient (α), extinction coefficient (k), refractive index (n), both the real (εr) and imaginary (εi) components of the dielectric constant have values of (1.8 eV), (3.11×104 cm−1), (0.111), (2.3), (5.36), and (0.517), respectively, for ZIS thin films at an Al ratio equal to 0.04.