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Here, we proposed a novel Al0.9Ga0.1N-delta-GaN QW by inserting an ultra-thin delta-GaN layer into a conventional Al0.9Ga0.1N QW active region. The physics from such QW design was investigated by 6-band k·p model and the structure was experimentally demonstrated by Plasma-assisted Molecular Beam Epitaxy (PAMBE). The calculated results show that the insertion of delta-GaN layer could successfully address the band mixing issue and QCSE, leading to a significant improvement in spontaneous emission rate as compared to that of Al0.55Ga0.45N QW at 260 nm. The 5-period Al0.9Ga0.1N-delta-GaN QW with 3-nm AlN barrier was grown on AlN/sapphire substrate by MBE with ~2-monolayer delta-GaN layer, which was evidenced by the cross-sectional transmission electron microscope. The two-photon photoluminescence spectrum presented a single peak emission centered at 260 nm from the grown Al0.9Ga0.1N-deltaGaN QW with a full width at half maximum of 12 nm, which shows that the demonstrated QW would be promising for high-efficiency UV LEDs. |
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