Site-dependent Eu~(3+) luminescence in GaN:Eu~(3+) epitaxial films studied by microscopic photoluminescence spectroscopy

摘要

We have studied photoluminescence (PL) properties of Eu~(3+)-doped GaN (GaN:Eu~(3+)) epitaxial films. The GaN:Eu~(3+) epitaxial films with a Eu~(3+) concentration of 1 at.% exhibit red luminescence due to intra-4f transitions of Eu~(3+) ions and blue luminescence due to bound excitons of GaN host crystals at 20 K. In microscopic PL imaging spectroscopy experiments, the intensities of the PL due to the Eu~(3+) ions and due to the bound excitons are sensitive to the monitored position. The PL mechanisms of the GaN:Eu~(3+) epitaxial films are discussed.