GaOOH:Eu3+ nanorods with different aspect ratios were prepared by hydrothermal method at 140 degrees C. alpha- and beta-Ga2O3:Eu3+ were converted from as-prepared GaOOH:Eu3+ particles by calcination at 500 and 850 degrees C, respectively. The products were characterized with X-ray diffraction (XRD), transmission electron microscope (TEM) and photolumineseence (PL). Results show that solution pH values play a key role in the formation of the GaOOH:Eu3+ powders with different morphologies and alpha- and beta-Ga-2:Eu3+ inherit the morphology of GaOOH:Eu3+ exactly. The photoluminescence characteristics of beta-Ga2O3:Eu3+ were also investigated. Experimental results reveal that the color purity of beta-Ga2O3:Eu3+ nanorods with high aspect ratio is enhanced in comparison with beta-Ga2O3:Eu3+ nanorods with low aspect ratio. (C) 2008 Elsevier B.V. All rights reserved.