Correlation between local atomic structure and ultraviolet luminescence of AlGdN thin films

The present study reports on the correlation between the local atomic structure and cathodoluminescent properties of Al1−xGdxN thin films grown by reactive rf magnetron sputtering at ultra-high vacuum conditions. Those thin films were characterised using X-ray absorption fine structure (XAFS) and cathodoluminescence (CL). From the CL measurements, we have observed a narrow intense ultraviolet emission at 318 nm which is originated from the intra-orbital f-f transition in Gd3+ ions. In order to understand the local atomic structure around the Al1−xGdxN (x=0.1 to 6.0 mol%) thin film, XAFS measurements have been carried out. Analysis of the local atomic structural results showed that both the large distance among Gd atoms and nitrogen vacancies in Al1−xGdxN lattice significantly contribute to the richness in the ultraviolet emission intensity.