Structural, Morphological and Optical Properties of (Mn, Al) Co-Doped ZnO Thin Films Prepared by Sol-Gel Dip Coating Method

Abstract

In this study, Aluminum (Al) and Manganese (Mn) co-doped ZnO thin films were successfully synthesized into glass substrates by the sol-gel dip-coating method with different Al concentrations (1%, 3%, and 5%). The structural, morphological, and optical properties of the obtained thin films were characterized by X-ray diffraction (XRD), Atomic force microscopy (AFM), and UV–VIS spectroscopy. XRD pattern revealed that the films have a polycrystalline hexagonal structure with a preferred orientation along (101) for undoped ZnO thin films, further the co-doped ZnO thin films show a shift in the preferred orientation to (002) direction without any Mn or Al related phases. The morphological analysis showed that the films have a uniform and dense ZnO grains, without any voids and cracks, and it was found that the surface roughness (RMS) increases from 8,27 to 14,43 nm when the Al doping concentration increased from 1% to 3%; however, when Al doping concentration is 5%, the RMS value decreased to 2,80 nm. From the optical analysis, the higher average transmittance was found to be corresponding to 5% Al doping concentration.