Fluorescence XAFS Analysis of Eu-Doped GaN Layers Grown by Organometallic Vapor Phase Epitaxy

We have investigated geometric structure of Eu-doped GaN grown by OMVPE at different growth temperature by using fluorescence XAFS measurement in order to elucidate the relationship between the local structure around Eu atoms and the PL properties. It is found that majority of Eu atoms doped in GaN are fundamentally substituted on Ga-site in GaN lattice. Moreover, it is revealed that degree of disorder in the layer grown at 900 degrees C is larger than that in the layers grown at 1000 and 1050 degrees C. These results indicate that the local structure around Eu atoms is closely related to the luminescence properties of the Eu-doped GaN layers.