Optimization of Gas Ambient for High Quality β-Ga₂O₃ Single Crystals Grown by the Optical Floating Zone Technique

β-Ga2O3 is a promising wide-bandgap semiconductor material for power electronic applications and as a conducting substrate for GaN growth. In this work, we report the growth of high quality single crystal β-Ga2O3 by the optical floating zone technique. A detailed study of the effect of gas ambient on the quality of Ga2O3 single crystals was carried out, with the structural quality investigated using Laue, single crystal and powder X-ray diffraction measurements, and the optical properties studied using transmission, photoluminescence, and Raman scattering measurements. Under optimized conditions high-quality, ∼ 1 cm diameter and ∼ 8-10 cm length Ga2O3 single crystals with X-ray FWHM values of ∼ 22'' for the (400) reflection, comparable to commercially available Ga2O3 wafers, could be demonstrated.