Local analysis of Eu²⁺ emission in CaAlSiN₃

We have investigated the local luminescence properties of Eu-doped CaAlSiN₃ by using low-energy electron beam (e-beam) techniques. The particles yield broad emission centered at 655 nm with a shoulder at higher wavelength under light excitation, and a broad band around 643 nm with a tail at 540 nm under e-beam excitation. Using cathodoluminescence (CL) in a scanning electron microscope (SEM), we have observed small and large particles, which, although with different compositions, exhibit Eu²⁺-related emissions at 645 and 635 nm, respectively. Local CL measurements reveal that the Eu²⁺ emission may actually consist of several bands. In addition to the red broad band, regularly spaced sharp peaks have been occasionally observed. These luminescence variations may originate from a variation in the composition inside CaAlSiN₃.