Dynamic stability, microstructure and optoelectronic performance of β-Ga2O3 single crystals prepared by the optical floating zone technique

Abstract

β-Ga₂O₃ [100] single crystals were prepared by the optical floating zone technique. As the rotation rate was increased from 12 to 15 rpm, the periodic growth stripes disappeared. The height of the melting zone increased from 11.9 mm to 12.8 mm with the increase in the growth rate from 10 to 15 mm h⁻¹. The full width at half maximum (FWHM) of the β-Ga₂O₃ single crystal obtained at V = 12 mm h⁻¹ is 0.139°. The formation of step-like pits was related with the dissociation characteristics of the crystal, whereas the formations of the trapezoidal and rhomboid pits were ascribed to the defects in the β-Ga₂O₃ single crystal. The edge dislocations are present on the (400) and (002) planes, but are absent on the (−601) plane. The Raman and ultraviolet absorption spectra indicated that the β-Ga₂O₃ single crystal prepared at V = 12 mm h⁻¹ and R = 15 rpm exhibited the highest quality.