Aluminum antimony alloy overlayers synthesized using the electrodeposition method: investigation of structural, optical, electrical properties, and DFT calculation

Abstract

This paper presents the synthesis of aluminum antimony (Al–Sb) alloy overlayers using an electrodeposition method for application in optoelectronic devices with various applied constant voltages (2, 4, 6, 8, and 10 V) controlled by a DC power supply. The corresponding energy dispersive x-ray spectroscope spectra show that elements including Al, Sb, and Cl were detected in the layers under all conditions of the applied voltage. The structural properties of the formulated compound layers were studied for their structural properties through x-ray diffraction patterns, and all the diffraction peaks exhibited a cubic phase structure. The Al–Sb alloy overlayers were incorporated with nanoparticles and had crystallite sizes ranging from ∼55 to 282 nm. The average transmittance T(λ) values in the visible to near-infrared region were ∼28.36%, 17.64%, 14.07%, 7.83%, and 5.84%, while the average reflectance R(λ) values were ∼3.80%, 1.69%, 1.30%, 0.47%, and 0.21% for applied voltages of 2–10 V, respectively. The energy band gap (Eg) existing in the overlayers was determined using Tauc's plot with the Kubelka–Munk function and it was inferred to be between 1.90 eV and 2.72 eV. The dispersion constants and energies of the prepared samples were also investigated. The 2 V applied voltage-treated Al–Sb alloy overlayers showed the highest average χ(1), χ(3), and n2 values of 0.088, 1.680 × 10−14 esu., and 4.082 × 10−13 esu., respectively. In addition, the resistance at various absolute temperatures was also recorded for the activation energy (EAC) values of the Al–Sb alloy overlayers with applied voltages of 2–10 V. Finally, ab initio calculations based on density functional theory were performed to support the experimental report of the Al–Sb systems. It was found that the calculated lattice constants are in good agreement with the experimental results, and a wider photoabsorption range performance for Al–Sb phase I in the axis of energy seems to be suitable for application as an optical device.