Towards Rare‐Earth‐Doped Optoelectronics: GGA+U Analysis of Eu ³⁺ ‐Doped ZnO Nanomaterials

This study employs first‐principles density functional theory (DFT) within the GGA + U framework to systematically investigate the structural, electronic, and optical properties of Eu 3+ ‐doped ZnO at concentrations of 3.13%, 4.17%, and 6.25%. The calculated lattice parameters and band gap of pristine ZnO are consistent with previously reported theoretical and experimental results, confirming the reliability of the adopted computational methodology. Substitutional Eu incorporation leads to concentration‐dependent lattice expansion and induces noticeable modifications in the electronic structure, while preserving the direct band‐gap nature of ZnO. The band gap shows a slight but systematic modulation with increasing Eu content, associated with Eu‐4f‐related impurity states near the band edges. Optical analysis reveals modified dielectric behavior, reduced ultraviolet (UV) absorption intensity, and enhanced absorption in the visible region, accompanied by a blue shift of the dominant UV absorption edge. These results demonstrate that Eu doping enables effective tuning of ZnO’s electronic and optical response, highlighting its potential for UV‐responsive optoelectronic applications such as UV photodetectors and transparent functional coatings.