In this work, the influences of thermal annealing and chemical passivation on the optical and electrical properties of ultraviolet light-emitting-diode (UV-LED) were investigated. The electroluminescence (EL) intensities of the LEDs under KOH treatment and thermal annealing increased by 48% and 81%, respectively compared to as-fabricated LED under current level of 10 mA. Cathodoluminescence (CL) mapping of UV-LEDs confirmed no variation of the density of the non-radiative recombination centers after surface treatments, and no obvious change in surface morphology was identified due to lacking of energy for surface atom migration. However, Raman spectroscopy indicates a relaxation of compressive strains inside the thin film after both thermal and chemical treatments, and conductive atomic force microscopy (c-AFM) also illustrated reduced leakage current after KOH passivation, which are responsible for the improved luminescence properties of UV-LEDs.

中文翻译：

---

在热处理和化学处理下提高紫外发光二极管 (UV-LED) 发光强度的机制

在这项工作中，研究了热退火和化学钝化对紫外发光二极管 (UV-LED) 光学和电学性能的影响。与在 10 mA 电流水平下制造的 LED 相比，经过 KOH 处理和热退火的 LED 的电致发光 (EL) 强度分别增加了 48% 和 81%。UV-LED 的阴极发光 (CL) 映射证实了表面处理后非辐射复合中心的密度没有变化，并且由于缺乏表面原子迁移的能量，没有发现表面形态的明显变化。然而，拉曼光谱表明在热处理和化学处理后薄膜内部的压缩应变松弛，