Thermal expansion of single-crystalline β-Ga2O3 from RT to 1200 K studied by synchrotron-based high resolution x-ray diffraction

Abstract

The anisotropic coefficient of thermal expansion for single-crystalline monoclinic β-Ga2O3 has been precisely measured by synchrotron-based high resolution x-ray diffraction in the temperature range from 298 to 1200 K. We derived values along the three main crystallographic directions, based on spacings for (600), (020), and (2¯04) lattice planes. αa changes non-linearly between 0.10 × 10–6 K–1 and 2.78 × 10–6 K–1 in the temperature range of 298 to 1200 K, while the values of αb and αc along the further two directions are nearly double. Within the Einstein model, we have numerically modeled the functional dependencies applying a single phonon mode.