Abstract AlGaN based Nanowire laser diodes (NW-LDs) grown on sapphire substrates have strong polarization induced electric field. Such electric field has the ability to degrade the optoelectronic characteristics of deep ultraviolet (DUV) NW-LD. In this work, a graded AlN composition AlxGa1-xN waveguide (WG) layer is used for the enhancement of DUV NW-LD performance. Grading of WG induces bulk polarization charges which compensates the effect of polarization induced electric field. According to the calculated optoelectronic characteristics of NW-LD, it is found that grading of n-type WG (n-WG) increases the optical confinement factor (OCF) by 82%. Fortunately, the proposed graded n-WG structure suppresses the leakage of optical field from active region and enhances carrier injection efficiency. Furthermore, if both n-WG and p-WG graded layers are used, the improvement is not obvious because of the current leakage from graded p-WG. Thus, graded n-WG based NW-LD gives highest 33.5% OCF with the lowest 7 mA and 4.59 V threshold current and voltage respectively.

中文翻译：

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通过在 AlxGa1-xN 波导中用梯度 AlN 成分感应体极化电荷来增强深紫外纳米线激光二极管的光电特性

摘要 在蓝宝石衬底上生长的基于 AlGaN 的纳米线激光二极管 (NW-LD) 具有很强的极化感应电场。这种电场能够降低深紫外 (DUV) NW-LD 的光电特性。在这项工作中，渐变的 AlN 成分 AlxGa1-xN 波导 (WG) 层用于增强 DUV NW-LD 性能。WG 的分级诱导体极化电荷，其补偿极化诱导电场的影响。根据计算出的 NW-LD 的光电特性，发现 n 型 WG (n-WG) 的分级使光学限制因子 (OCF) 提高了 82%。幸运的是，所提出的渐变n-WG结构抑制了有源区的光场泄漏并提高了载流子注入效率。此外，如果同时使用 n-WG 和 p-WG 渐变层，由于渐变 p-WG 的电流泄漏，改进并不明显。因此，基于分级 n-WG 的 NW-LD 分别提供最高 33.5% 的 OCF，最低 7 mA 和 4.59 V 阈值电流和电压。