Significant structural, chemical, and morphological properties induced by Mg 2+ doping in γ-Al 2 O 3 nanofilms spin-coated

This study reports the synthesis and characterisation of pure and Mg-doped Al2O3 thin films deposited on glass quartz and silicon substrates by the spin-coating technique. The influence of Mg²+ doping on the chemical, structural, morphological, and optical properties of Al2O3 films was investigated using XPS, XRD, SEM, AFM, and uv–visible spectroscopy. XPS analysis revealed well-defined Al2p and O1s peaks recorded at approximately 74 and 531 eV, respectively, confirming the formation of Al–O bonds characteristic of Al2O3. XRD patterns confirmed the presence of the γ-Al2O3 phase. Mg²+ incorporation was found to influence both the position and intensity of the diffraction peaks, indicating modifications in the crystal structure and crystallite size. Morphological investigations by SEM and AFM demonstrated that Mg doping alters the microstructure of Al2O3 films, leading to a reduction in grain size and the formation of a more homogeneous surface with improved texture and lower surface roughness. UV–visible spectroscopy confirms the optical transparency of the Al2O3 films, which exhibit a high transmittance in the range of approximately 60–70%. A slight reduction in the optical band-gap energy, from 4.2121 to 4.1590 eV, is observed and can be attributed to Mg²+ effect. The substitution of Mg²+ for Al³+ necessitates charge compensation, leading to the generation of F+-type oxygen vacancies. F+ introduces localised states within the band gap, facilitating electronic transitions and contributing to the enhanced optical properties of the films. Mg²+ doping refines the structural, morphological, and optical properties of γ-Al2O3, creating a promising framework for advanced technological applications.