Transparent rare earth-doped gallium oxide ceramics with oriented microstructure

Gallium oxide (Ga₂O₃) has attracted much attention due to its promising applications in optical and electronic devices, while it is difficult to fabricate high-quality Ga₂O₃ transparent ceramics because of the non-cubic crystal structure. In this work, fully densified undoped and rare earth (RE = Tb, Dy. Er)-doped Ga₂O₃ transparent ceramics were successfully fabricated by using spark plasma sintering (SPS) and co-precipitated ceramic powders. Both the powders and ceramics showed pure monoclinic β- Ga₂O₃ crystal structure and unique orientation. After sintering by SPS for 30 min, all the ceramics reached a relative density higher than 99.21%. The total transmittance of RE-doped Ga₂O₃ transparent ceramics ranges from 60% to 69% originating from the oriented and dense microstructures. The photoluminescence spectra and fluorescence lifetime of RE-doped Ga₂O₃ transparent ceramics confirm characteristics of energy transfers corresponding to Tb³⁺, Dy³⁺, or Er³⁺ ions in the visible and NIR spectral region. This study demonstrates that oriented RE-doped Ga₂O₃ transparent ceramics have great potential to be used in various optical applications.