Preparation, characterization and luminesence of erbium and holmium doped nanocrystalline β -Ga2O3

Luminescence from lanthanide doped materials has generated much interest in recent years, due to the their use in a variety of appliations such as phospors, solid state lasers, optical amplifiers and optical waveguides especially in NIR region where optical communication systems operate [1]. Gallium sesquioxide β -Ga2O3 is a wide band gap material with a gap of ≈ 4.9 eV and becomes n-type semiconductor with slight oxygen deficiency. Due to the wide band gap which makes it transparent to the visible emission, β -Ga2O3 is a promising host material for lanthanide ions. Samples of Ga2O3:Er and Ga2O3:Ho doped with 1% of Er3+ and Ho3+ were prepared applying a solution combustion synthesis procedure using ethylene glycol [2]. Materials are characterized by using powder X-ray diffraction and transmission electron microscopy (TEM). Luminescence properties of Ga2O3:Er and Ga2O3:Ho are studied using Raman spectrometers with excitation in NIR and visible. Intense luminescence is observed in NIR and visible region for both sampels. Intensity is comparable and for erbium even stronger than in doped Y2O3. All bands present in spectra are assigned to f → f transitions of Er3+ and Ho3+. Combustion synthesis using ethylene glycol as the fuel is a fast and inexpensive method for synthesis of nanocrystalline oxide materials doped with lanthanide ions. This study clearly demonstrates the use of Raman spectrometers for studying luminescence of lanthanide ions.