The surface tension of Ga₂O₃ melt measured by a drop-weight method in an optical floating-zone furnace

Abstract The surface tension of Ga₂O₃ melt is successfully measured using a drop-weight method in an optical floating-zone furnace that we have developed. The method is verified to be feasible by measuring the surface tension value of TiO₂ melt and then comparing it with values in previous reports determined by other methods. We find that the surface tension of Si-doped Ga₂O₃ melt increases with the decrease in the Si doping concentration and reaches 527.9 mN m⁻¹ for pure Ga₂O₃ melt. The surface tension of the unintentionally doped Ga₂O₃ melt is also measured to be 519.3 mN m⁻¹ in the presence of some common contaminants appearing in Czochralski and edge-defined film-fed growth methods, including Ir, Al, and Si.