High-efficiency III-nitride deep-ultraviolet (DUV) lasers and light-emitting diodes (LEDs) with emission wavelengths of 240–260 nm are extremely difficult to realize due to large defect density from III-nitride materials and existence of optical polarization crossover from conventional AlGaN-based quantum wells (QWs). Free-standing wurtzite AlGaN templates have been studied and developed recently; however, the physics and optical properties of AlGaN-based emitters on AlGaN templates are still relatively lacking. Therefore, this work theoretically investigates the optical properties and quantum efficiencies of the AlGaN-based QW on AlGaN substrates. The physics analysis based on a self-consistent 6-band k⋅p model shows the transverse electric (TE)-polarized optical gain increases from 558 cm−1 by using Al0.51Ga0.49N/AlN QW on the AlN substrate to 2875 cm−1 by using Al0.48Ga0.52N/Al0.72Ga0.28N QW on the Al0.72Ga0.28N substrate at 260 nm, which is attributed to the reduced strain effect and valence band rearrangement by using the AlGaN substrate. Correspondingly, the radiative recombination efficiency increases 1.66–4.43 times based on different Shockley–Read–Hall coefficients, indicating the promising potential of the use of the AlGaN substrate for high-efficiency DUV lasers and LEDs.

中文翻译：

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高效 240-260 nm 深紫外激光器和发光二极管在 AlGaN 衬底上的物理学

由于 III 族氮化物材料的大缺陷密度和光偏振交叉的存在，发射波长为 240-260 nm 的高效 III 族氮化物深紫外 (DUV) 激光器和发光二极管 (LED) 极难实现来自传统的基于 AlGaN 的量子阱 (QW)。最近研究和开发了自立式纤锌矿AlGaN模板；然而，AlGaN 模板上基于 AlGaN 的发射器的物理和光学特性仍然相对缺乏。因此，这项工作从理论上研究了 AlGaN 衬底上基于 AlGaN 的 QW 的光学特性和量子效率。基于自洽 6 波段 k⋅p 模型的物理分析显示，通过使用 Al0.51Ga0，横向电 (TE) 偏振光增益从 558 cm-1 增加。通过在 260 nm 处在 Al0.72Ga0.28N 衬底上使用 Al0.48Ga0.52N/Al0.72Ga0.28N QW 将 AlN 衬底上的 49N/AlN QW 提高到 2875 cm-1，这归因于降低的应变效应和价带使用 AlGaN 衬底进行重排。相应地，基于不同的 Shockley-Read-Hall 系数，辐射复合效率增加了 1.66-4.43 倍，表明使用 AlGaN 衬底用于高效 DUV 激光器和 LED 的潜力很大。