Unveiling the impact of excessive dopant content on morphology and optical defects in carbonation synthesis of nanostructured Al-doped ZnO

The metal doping in the ZnO structures alters its electronic structure and induces trap states, resulting in the novel functionalities. This study investigates Al-doped ZnO nanostructures (0–20 at.%) synthesized via carbonation. Doping significantly influenced crystallography, physical, and optical properties, assessed through diverse analytical methods. X-ray diffractometer data revealed altered crystallography (texture, crystallite size, lattice constants, ZnO bond length, interplanar angles) and physical traits (strain, stress, Young's modulus, strain energy). Al doping at 10 at.% transformed morphology from round nanoparticles to nanoplates, supported by Brunau–Emmet–Teller analysis showing improved surface area. The energy bandgap varied with Al content. Photoluminescence spectra displayed distinct optical defects (Zni, VZn, and Oi) and emissive wavelengths. XPS confirmed Al3+ integration into ZnO. The study elucidates ZnO crystal modification based on various Al concentrations, discussing excessive dopant effects on morphology and optical defects in combination with structural changes and intrinsic defects.