Synthesis and characteristics of pure β-Ga₂O₃ and Tb³⁺ doped β-Ga₂O₃ hollow nanostructures

The pure β-Ga₂O₃ and Tb³⁺ doped β-Ga₂O₃ hollow nanostructures with various Tb ³⁺ concentrations were prepared by hydrothermal and cacination processes. The X-ray diffraction patterns indicate that the core-shell structures are amorphous phase before calcination and perfectly crystallized β-Ga₂O₃ hollow nanostructures were obtained at 800 C. The sharp and intense band absorption at 1384 cm^-1, which was attributed to the Ga(OH)CO₃ shell, was observed by Fourier transform infrared. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy investigations showed β-Ga ₂O₃ hollow nanostructures with diameters of about 200 nm and thicknesses of about 20~30 nm. The green emission spectra of Tb³⁺ doped β-Ga₂O₃ hollow nanostructures as a function of Tb³⁺ ions were observed due to the ⁵D₄→ ⁷F_J transition. The Tb³⁺-doped β-Ga ₂O₃ hollow nanostructures showed the highest green emission intensity at 7 mol% of Tb³⁺ ions.