Catalytic synthesis and photoluminescence of β-Ga2O3 nanowires

Abstract

Monoclinic gallium oxide $\mathrm{(\beta -}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}})$ nanowires were synthesized by heat treating a composite material of GaAs and pre-evaporated Au at $\text{1240\hspace{0.05em}°}\mathrm{C}$ in dry oxygen atmosphere. The catalytic Au metal generated liquid nanoclusters that serve as reactive sites confining and directing the growth of $\mathrm{\beta -}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ nanowires during the vapor-liquid-solid growth process. The $\mathrm{\beta -}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ nanowires have diameters ranging from 20 to 50 nm and lengths of several micrometers. Photoluminescence measurement under excitation at 250 nm shows that the bulk $\mathrm{\beta -}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ nanowires have a stable blue emission at 475 nm and an ultraviolet emission at 330 nm, which may be related to the defects such as the oxygen vacancy and the gallium–oxygen vacancy pair.