ABSTRACTHigh-luminance red-emitting thin-film electroluminescent (TFEL) devices have been developed using Ga2O3 phosphor thin films prepared by a sol-gel deposition method. Single-insulating-layer-type TFEL devices were fabricated by depositing a Cr- or a Eu-activated Ga2O3 phosphor thin film onto a thick BaTiO3 ceramic sheet insulator. The Ga2O3:Cr or Ga2O3:Eu thin-film emitting layer was prepared by a sol-gel process using gallium acethylacetonate (Ga(C5H7O2)3) as the Ga source with Cr(C5H7O2)3 or EuC13 as the dopant source, respectively. A high red luminance of 622 cd/m2 was obtained for a Ga2O3:Cr TFEL device driven by a sinusoidal wave voltage at 1 kHz.