Atomic Layer Deposition and Electroluminescence of Er-Doped Polycrystalline Lu₃Ga₅O₁₂ Nanofilms for Silicon-Based Optoelectronics

Er-doped Lu3Ga5O12 garnet(LuGG:Er)nanofilms are obtained by the crystallization of Lu2O3/Er2O3/Ga2O3 nanolaminatesfabricated using atomic layer deposition on silicon. The temperaturerequired for garnet crystallization is independent of the Lu/Ga ratiosand the interlayer thickness in the nanolaminates, and a thresholdtemperature of 800 & DEG;C is identified, ascribing to the easiermigration and reconstruction of the gallium component. The efficienciesand lifetime of the characteristic 1.53 & mu;m electroluminescence(EL) from Er3+ ions within polycrystalline LuGG:Er nanofilmsare correlated with the Lu/Ga ratios, and a higher doping concentrationof 3.5 mol % is preferable. The optimal device exhibits an externalquantum efficiency of 2.5% and a power efficiency of 5.2 x 10(-4), with the maximum optical power density reaching4.9 mW/cm(2) and the fluorescence lifetime longer than 2ms. The electron injection within the LuGG:Er devices follows thetrap-assisted tunneling mechanism under the operating electric field,resulting in the impact excitation of Er3+ ions. The prototypeLuGG:Er device operates stably for & SIM;9.2 h while maintaining90% of the initial EL intensity. This work further explores the depositionof compound oxide nanofilms with controlled composition and crystallinityat low temperature and Si-based garnet nanofilms for the optoelectronicapplications.