Effects of Mg-codoping on the 1540-nm photoluminescence of Er-implanted GaN

The similar to 1540-nm Er3+ photoluminescence (PL) and photoluminescence ex citation (PLE) spectra of Er-implanted Mg-codoped GaN (GaN:Er+Mg) indicate that the excitation efficiency of a specific Er3+ center among different Er 3+ centers existing in Er-implanted GaN is selectively enhanced. compared t o Er-implanted undoped GaN (GaN:Er). In GaN:Er+Mg, the 1540-nm PL peaks cha racteristic of the so-called "violet-pumped" Er3+ center and the similar to 2.8 - 3.4 eV (violet) PLE band are significantly strengthened by the Mg-do ping. The intra-f absorption PLE bands associated with this "violet-pumped" center are also enhanced by this doping. The 1540-nm FL peaks originating from the "violet-pumped" center dominate the above-gap-excited Er3+ PL spec trum of GaN:Er+Mg whereas they are unobservable under above-gap excitation in GaN:Er. All of these results indicate that Mg doping increases the effic iency of trap-mediated excitation of Er3+ emission in Er-implanted GaN.