Effect of growth temperature on Eu-doped GaN layers grown by organometallic vapor phase epitaxy

We investigated the effect of growth temperature on the luminescence properties of Eu-doped GaN layers grown by organometallic vapor phase epitaxy (OMVPE). The dominant photoluminescence (PL) peak intensity at 621 nm, due to the intra-4f shell transitions of D-5(0)-F-7(2) in Eu3+ ions, became the highest when the sample was grown at 1000 degrees C. We consider three reasons for this temperature dependence. Firstly, Eu concentration became the highest when the sample was grown at 1000 degrees C. Secondly, Eu-doped GaN layer grown at 1000 degrees C had the local structure of Eu-3+ ions, which emitted at 621 nm preferentially. Thirdly, the density of screw and mixed dislocations decreased with increasing growth temperature. These results indicated that an appropriate growth temperature exists for strong Eu-related luminescence from Eu-doped GaN layer grown by OMVPE. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim