Solid solutions based on indium oxide with additions of HfO₂, CeO₂, and TiO₂ and some of their properties

Abstract

Methods of x-ray structural analysis and measurements of the mass of specimens before and after annealing and their electrophysical properties are used to investigate the formation of solid solutions based on indium oxides with additions of HfO₂, CeO₂, TiO₂ in the range 800 – 1450 – 1600°C in air. It is established that in the system In₂O₃ — HfO₂ annealed at 1200°C, small additions of HfO₂ (0.5%) stabilize a mixture of two cubic phases. After annealing at 1450 and 1600°C a bounded region of a substitutional — interstitial — subtractive solid solution is formed. These solid solutions are preserved after successive lengthy isothermal annealings in the interval 500 – 1200°C. In the system In₂O₃ - CeO₂ the interaction occurs at 1450°C and above with the formation of a substitutional-subtractive solid solution. Specimens containing a single-phase solid solution possess highly mobile charge carriers. All the properties of the specimens are preserved after isothermal annealing in the range 500 – 1200°C. In the system In₂O₃ -TiO₂ with the concentration of TiO₂ ranging within 0.5 – 2% a substitutional - interstitial - subtractive solid solution is formed, and for a TiO₂ concentration of 2 – 5% a substitutional-subtractive solid solution is formed; above the indicated concentrations the mixture contains the compound In₂TiO₅ of rhombic modification. The materials of this system possess a high vaporizability.