Luminescence properties of Ca- and Yb-codoped SiAlON phosphors

Luminescence properties of SiAlON phosphors codoped with Ca and Yb were investigated by changing the host lattice composition. These modifications of the host lattice were obtained by replacing SiN bonds by AlN and AlO bonds. Their photoluminescence (PL) and cathodoluminescence (CL) properties were measured and compared with each other. PL allows observing the influence of the host lattice modifications by measuring wider areas. CL can excite all luminescent centers, in particular the UV luminescence centers, even if their amount is small. Thus, two additional peaks in the ultraviolet and infrared regions were observed in CL, which is not observed by PL. This work suggests that the combination of PL and CL gives more understanding about the luminescence of SiAlON phosphors, in particular the role of the secondary phases on their properties.