Single crystal growth and optical properties of a transparent perovskite oxide LaInO₃

Transparent LaInO₃ single crystals have been grown using the optical floating zone method. Optimal growth, resulting in the highest optical transparency and best crystallinity, has been found at a growth speed of 15 mm/h and an O₂ gas pressure of 10 bar. Under these conditions, single crystals as large as ∼4 × 4 mm² have been obtained. Chemical compositions and structural analyses reveal that the resulting LaInO₃ single crystal is stoichiometric without any impurity phase and forms an orthorhombic perovskite structure. Optical transmission spectra exhibit multiple optical transitions in a wide spectral range (0.5-4.2 eV). Although the main optical absorption occurs at ∼4.13 eV, weak absorption starts to develop from ∼1.4 eV, in agreement with an activation energy of ∼0.7 eV derived from electrical resistivity measurements. The dielectric constant ε is found to be 23.7 at room temperature. This LaInO₃ single crystal can be used as a transparent perovskite substrate for growing oxide semiconductors with lattice constants close to ∼4.12