Eu concentration dependence on structural and optical properties of Eu-doped GaN

The structural and optical properties of europium-doped GaN were studied. The Eu-related luminescence was observed at 622 nm and originated from the intra-4f transition of the Eu3+ ion. The intensity of the luminescence increased as the Eu concentration increased up to about 3 at%, and then abruptly decreased. In-situ reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD) were carried out to study this luminescence quenching, and it was discovered that there is a close relationship between the luminescence intensity at 622 nm and the structural properties. The cause of the concentration quenching is likely related to the polycrystalline growth as well as to the formation of EuN. (C) 2004 WILEY-VCH Vertag GmbH & Co. KGaA, Weinheim.