The 1540nm 4I13/2 to 4I15/2 Er3+ photoluminescence and photoluminescence excitation spectra of Er-implanted Mg-doped samples revealed a selective enhancement of one of the 9 different Er3+ centres which had previously been observed in similar studies of Er-implanted undoped material. These Er3+ photoluminescence spectra were selectively excited by pumping wavelengths that corresponded to broad-band, below-gap absorption bands which were associated with various Er3+ centres. In Er-implanted Mg-doped samples, both the 1540nm photoluminescence spectrum that was characteristic of so-called violet-pumped Er3+ centres, and the 2.8 to 3.4eV (violet) photoluminescence excitation band that permitted its selective excitation, were significantly enhanced by Mg doping. The violet-pumped photoluminescence center also dominated the above-gap excited Er3+ photoluminescence spectrum of Er-implanted Mg-doped material. It was almost unobservable under above-gap excitation conditions in Er-implanted undoped samples. The results confirmed the hypothesis that suitable co-dopants could increase the efficiency of trap-mediated above-gap excitation of Er3+ emission in Er-implanted material.

Selective Enhancement of 1540nm Er3+ Emission Centers in Er-Implanted GaN by Mg Co-Doping S.Kim, S.J.Rhee, X.Li, J.J.Coleman, S.G.Bishop: Applied Physics Letters, 2000, 76[17], 2403-5