Advanced Physical Research

Pure and Al-doped ZnO nanostructures were studied by photoluminescence spectroscopy and density functional theory calculations. The PL spectra were measured under 325 nm and 785 nm excitation in the ultraviolet, visible and near-infrared regions. Pure ZnO showed near-band-edge ultraviolet emission around 380-390 nm and weaker defect-related visible emission. After Al doping, the emission intensity increased significantly, indicating enhanced radiative recombination and modification of defect states. The broad visible band at 500–700 nm and near-infrared emission at 700-760 nm were attributed to intrinsic defects and Al-induced donor-related recombination centers. CIE analysis showed warm-white emission with coordinates of about x = 0.400 and y = 0.457, CCT ≈ 4011 K and CRI ≈ 79. DFT calculations confirmed that Al substitution in the ZnO lattice introduces donor-type electronic states near the Fermi level and modifies the band structure. The combined experimental and theoretical results show that Al-doped ZnO nanostructures are promising for white-light emission, optical sensors and optoelectronic devices.