Polyaminocarboxylate promoted synthesis of Hafnium/ Zirconium substituted anion excess In2O3: Structure,optical and electrical conductivity properties

The current study aimed to generate Hf/Zr substituted In₂O₃ with the ultimate aim of realizing a potential transparent conducting oxide. We applied a co-complexation method to bring the reactively dissimilar In and Hf/Zr together in one oxide network. We prepared an EDTA complex containing an equimolar concentration of In and Hf/Zr and examined their characteristics with FTIR and TG-DSC traces. Rietveld refinement results of calcined complexes and their Raman spectra confirmed the formation of anion excess bixbyite structure for (In_1-xM_x)₂O_3+δ (M = Hf, Zr, and x = 0.50). The lattice expanded after substituting with Hf/Zr, and the optical bandgap increased from 2.87 eV (In₂O₃) to 3.20–3.60 eV. The high percentage reflectance in the visible region and absorbance in the UV region fulfilled some of the prerequisites of transparent conducting oxide. Electrical resistivity reduced up to two orders in magnitude with increasing temperature for Hf and Zr incorporated In₂O₃.