Control of Eu Luminescence Centers by Codoping of Mg and Si into Eu-Doped GaN

The effects of Mg and Si codoping on Eu luminescence properties have been investigated in Eu-doped GaN (GaN:Eu). The Mg codoping into GaN:Eu produced novel luminescence centers consisting of Eu and Mg, and increased photoluminescence (PL) intensity in Eu,Mg-codoped GaN (GaN:Eu,Mg). However, this increased PL intensity was quenched by thermal annealing in N 2 ambient, which is due to activation of Mg acceptors. In GaN:Eu,Mg codoped additionally with Si (GaN:Eu,Mg,Si), on the other hand, the Eu--Mg centers disappeared, while an additional luminescence center appeared. Furthermore, the additional luminescence center showed no quenching under N 2 annealing because Si donors compensated for the Mg acceptors in GaN. Thermal quenching of the luminescence center was also approximately half of that in GaN:Eu. These results indicate that the codoping with additional impurities in GaN:Eu is a powerful technique to control Eu luminescence centers for realization of improved device performance in red light-emitting diodes using GaN:Eu.