Structural and Physical Property Analysis of ZnO–SnO2–In2O3–Ga2O3 Quaternary Transparent Conducting Oxide System

The increasing demand in the diverse device applications of transparent conducting oxides (TCOs) requires synthesis of new TCOs of n- or p-type conductivity. This article is about materials engineering of ZnO–SnO2–In2O3–Ga2O3 to synthesize powders of the quaternary compound Zn2−xSn1−xInxGaxO4−δ in the stoichiometry of x = 0.2, 0.3, and 0.4 by solid state reaction at 1275 °C. Lattice parameters were determined by X-ray diffraction (XRD) technique and solubility of In3+ and Ga3+ in spinel Zn2SnO4 was found at 1275 °C. The solubility limit of In3+ and Ga3+ in Zn2SnO4 is found at below x = 0.4. The optical transmittance approximated by the UV–Vis reflectance spectra showed excellent characteristics while optical band gap was consistent across 3.2 eV with slight decrease along increasing x value. Carrier mobility of the species was considerably higher than the older versions of zinc stannate spinel co-substitutions whereas the carrier concentrations were moderate.