Correlation between Structure, Chemistry, and Dielectric Properties of Iron-Doped Gallium Oxide (Ga_2–<i>x</i>Fe_<i>x</i>O₃)

Abstract

Iron (Fe)-doped gallium oxide (Ga2O3) compounds (Ga2–xFexO3; x = 0.0–0.3; referred to GFO) were synthesized by the standard high-temperature solid-state chemical reaction method. X-ray diffraction analyses confirmed that the sintered GFO compounds stabilized in monoclinic crystal structure with C2/m space group. Local structure and chemical bonding analyses using XANES revealed that the Fe occupies octahedral and tetrahedral sites similar to Ga in parent Ga2O3 lattice without considerable changes in the local symmetry. Morphology of the GFO compounds is characterized by the presence of rod-shaped particle (from around 2.0–3.5 μm) features. The energy dispersive X-ray spectroscopy confirmed the chemical stoichiometry of the GFO compounds, where the atomic ratio of the constituted elements is in accordance with the calculated concentration values. The frequency- and temperature-dependent dielectric properties of the GFO compounds exhibited the traditional dielectric dispersion behavior. Relatively high dielectric constant at lower frequencies is attributed to Maxwell–Wagner type of dielectric relaxation, which primarily originated from uncompensated charges at electrode material interface. On the basis of the results and analyses, the effect of Fe content on the crystal structure, chemical bonding and local structure, and dielectric properties of Ga2–xFexO3 compounds is established.