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

Abstract

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 Å, such as doped BaSnO3.