Concentration quenching of Eu-related luminescence in Eu-doped GaN

The dependence of Europium (Eu)-related luminescence intensity on the Eu concentration in Eu.-doped GaN was studied. This luminescence is observed at 622 nm and originates from the intra-4f transition of the Eu3+ ion. The intensity of the luminescence increased with increasing Eu concentration, up to about 2 at. %, and then abruptly decreased. It was found that polycrystalline growth began to be induced at Eu concentrations of more than 2 at. %. In addition, clear evidence for the formation of EuN compounds was obtained by x-ray diffraction and extended x-ray absorption fine structure analysis. The cause of the concentration quenching is likely to be related to the polycrystalline growth as well as EuN formation. (C) 2004 American Institute of Physics.