Investigating the Local Coordination and Electronic States of Fe-Doped Graphitic ZnO Using X-ray Absorption Spectroscopy

This study investigates the electronic structure and local coordination environment of Fe-doped graphitic ZnO (gZnO) through X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analysis at the Fe and Zn K-edges. XANES spectra of the samples were recorded for Fe doping concentrations of 2, 4, and 6%, along with that of the Fe2O3 standard sample. Key spectral features, such as the pre-edge and absorption edge, indicate that Fe ions predominantly adopt a +3 oxidation state within the ZnO matrix. Polarization-dependent XANES measurements reveal distinct in-plane and out-of-plane electronic environments, particularly pronounced in the 2% Fe-doped sample. The XANES simulations, assuming a model of stacked graphitic ZnO monolayers with Fe substitutions, closely match with the experimental data, validating the layered structural model. Fourier transform EXAFS spectra indicate preferential orientation of the gZnO layers in-plane of the substrate. The magnetic measurements indicate room-temperature ferromagnetism, highlighting its potential applications. These findings offer comprehensive insights into the structural and electronic properties, along with the possible applications of Fe-doped ZnO. This has significant implications for the development of ZnO-based two-dimensional (2D) materials in advanced technological applications.