A full structure 290-nm ultraviolet light-emitting diode (UV-LED) with a nanoporous n-AlGaN underlayer was fabricated by top via hole formation followed by high-voltage electrochemical etching. The 20 to 120 nm nanopores were prepared in regular doped n-AlGaN by adjusting the etching voltage. The comparison between the Raman spectrum and the photoluminescence wavelength shows that the biaxial stress in the nanoporous material is obviously relaxed. The photoluminescence enhancement was found to be highly dependent on the size of the pores. It not only improves the extraction efficiency of top-emitting transverse-electric (TE)-mode photons but also greatly improves the efficiency of side-emitting transverse-magnetic (TM)-mode photons. This leads to the polarization change of the side-emitting light from −0.08 to −0.242. The intensity of the electroluminescence was increased by 36.5% at 100 mA, and the efficiency droop at high current was found to decrease from 61% to 31%.

中文翻译：

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290-nm UV-LED 中纳米多孔 n-AlGaN 底层的 TM 模式增强和下降

具有纳米多孔 n-AlGaN 底层的全结构 290 nm 紫外发光二极管 (UV-LED) 通过顶部通孔形成和高压电化学蚀刻制造。通过调节蚀刻电压在常规掺杂的 n-AlGaN 中制备 20 至 120 nm 纳米孔。拉曼光谱与光致发光波长的比较表明，纳米多孔材料中的双轴应力明显松弛。发现光致发光增强高度依赖于孔的大小。它不仅提高了顶发射横电 (TE) 模式光子的提取效率，而且大大提高了侧发射横磁 (TM) 模式光子的效率。这导致侧向发射光的偏振变化从 -0.08 到 -0.242。