Preparation and photoluminescence properties of Eu-doped αα- and ββ- Ga2O3 phosphors

GaOOH:Eu3+ powders in ellipsoid-like and spindle-like shapes have been successfully prepared by surfactant-free hydrothermal process. αα- and ββ-Ga2O3:Eu3+ were converted from as-prepared GaOOH:Eu3+ particles by dehydration at 500 ∘C and 850 ∘C, respectively. The products were characterized with XRD (X-ray diffraction) and FE-SEM (field emission scanning electron microscopy). Results show that solution pH values play a key role in the formation of the GaOOH:Eu3+ powders with different morphologies and αα- and ββ-Ga2:Eu3+ inherit the morphology of GaOOH:Eu3+ exactly. The photoluminescence characteristics of αα- and ββ-Ga2O3:Eu3+ were also investigated. Experimental results reveal that the emission intensity of spindle-like (or ellipsoid-like) ββ-Ga2O3:Eu3+ is superior to that of αα-Ga2O3:Eu3+ with the same morphology. Moreover, the color purity of ββ-Ga2O3:Eu3+ is enhanced in comparison with αα-Ga2O3:Eu3+.