Al-doped Ag2S nanostructures: Ultrasonic synthesis and physical properties

Abstract

Un- and aluminum (Al)-doped silver sulfide (Ag2S) nanostructures were grown by the sonochemical method. The samples were studied by employing various identification methods including X-ray diffraction (XRD), field emission electron microscopy (FESEM), photoluminescence (PL), Raman and UV–Visible. The results showed that adding Al dopant shifts the diffraction peaks to higher angles and reduces their intensity. Furthermore, the size of the nanocrystal was reduced compared to the undoped sample. It was found that the strain in the doped samples is greater than the un-doped sample by the use of Hall-Williamson (W-H) method. FESEM images demonstrate the composition of spherical forms of nanostructures, which is converted to a quadrilateral shape by adding dopant. PL analysis illustrated the presence of emission bands in the visible region that was resulted by the emission of the near band edge (NBE), as well as the concentration of the density and type of defects. Moreover, Al increased the optical energy band gap of the nanostructures. Finally, the influence of the parameters affecting the crystalline and the optical properties of the material over the growth process was investigated using Raman analysis.