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The potential of Ge nanoparticles (NPs) embedded in Al 2 O 3 with tunable effective optical bandgap values in the range of 1.0&-3.3 eV to induce enhanced Er 3+ light emission is investigated. We demonstrate nonresonant indirect excitation of the Er 3+ ions mediated by the Ge NPs at room temperature. Efficient Er 3+ light emission enhancement is obtained for Ge NPs with large effective optical bandgaps in the range of 1.85 to 2.8 eV. The coupled Ge NP&-Er emission shows a negligible thermal quenching from 10 K to room temperature that is related to Er 3+ de-excitation through thermally activated defect states.