Broadband sensitization of 1.53μm Er3+ luminescence in erbium-implanted alumina

Experimental evidence of an efficient broadband sensitization mechanism in erbium-implanted alumina is presented. Alumina thin films were deposited by plasma-enhanced chemical vapor deposition using trimethyl-amine alane and nitrous oxide. The as-grown films, together with sapphire crystals, were implanted with erbium. Photoluminescence excitation spectra showed that erbium-implanted sapphire crystals exhibit characteristic Er3+ luminescence at 1.53μm only when pumped resonantly. In contrast, erbium-implanted alumina thin films exhibit 1.53μm luminescence even when pumped at wavelengths outside Er3+ absorption bands. We postulate that the sensitizing species is either small nanoclusters of aluminum or pairs of aluminum ions.