Ce-doped SiO_xN_y and SiAlON matrices are promising materials for blue LED applications. The uniqueness of this approach sterns from the fact that SiO_xN_y, as a host, combines specific properties of individual SiO_x and SiN_y matrices like solubility, efficient emission, 5 eV gap etc. with a broad excitation range (400 to 500 nm) of Ce~(3+) due to the 4f-5d transitions. Furthermore, the co-doping with aluminum enhances the Ce~(3+) emission. In this work, we fabricated electroluminescent devices using SiO_xN_y:Ce~(3+) and SiAlON: Ce~(3+) as an active layers and studied the resulting emission under optical and electrical excitation as a function of nitrogen, cerium and aluminum concentrations. I-V measurements were conducted to determine the SiO_xN_y:Ce~(3+) layer electrical parameters. The transport through the devices obeys a Poole-Frenkel conduction mechanism. It was demonstrated that by optimizing the SiO_xN_y:Ce~(3+) material growth parameters an improvement of electroluminescence yield can be achieved with maximum intensity achieved for devices with Ce content of 4 at.%.
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