Spontaneously grown, self-aligned AlGaN nanowire ultraviolet light emitting diodes still suffer from low efficiency partially because of the strong surface recombination caused by surface states, i.e., oxidized surface and high-density surface states. Several surface passivation methods have been introduced to reduce surface nonradiative recombination by using complex and toxic chemicals. Here, we present an effective method to suppress such undesirable surface recombination of the AlGaN nanowires via diluted potassium hydroxide (KOH) solution, a commonly used chemical process in semiconductor fabrication that is barely used as surface passivation solution in self-assembled nitride-based nanowires. The transmission electron microscopy investigation on the samples reveals almost intact nanowire structures after the passivation process. We demonstrated an approximately 49.7% enhancement in the ultraviolet light output power after a 30 s KOH treatment on AlGaN nanowires grown on titanium-coated silicon substrates. We attribute such a remarkable enhancement to the removal of the surface dangling bonds and oxidized nitrides (Ga–O or Al–O bonds) at the surface as we observe the change of the carrier lifetime before and after the passivation. Thus, our results highlight the possibility of employing this process for the realization of high-performance nanowire UV emitters.

中文翻译：

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表面钝化的AlGaN纳米线，用于增强紫外线发光二极管的发光

自发生长的自对准AlGaN纳米线紫外发光二极管仍然受到效率低的影响，部分原因是由于表面状态（即氧化的表面状态和高密度的表面状态）引起的强表面重组。已经引入了几种表面钝化方法，以通过使用复杂而有毒的化学物质来减少表面非辐射重组。在这里，我们提出了一种有效的方法，以通过稀释的氢氧化钾（KOH）溶液抑制AlGaN纳米线的这种不良表面重组，这是半导体制造中常用的化学工艺，几乎不用作自组装氮化物基纳米线的表面钝化溶液。 。对样品的透射电子显微镜研究表明，钝化过程后几乎完整的纳米线结构。我们对在涂钛的硅基板上生长的AlGaN纳米线进行了30 s KOH处理后，证明了紫外线输出功率提高了约49.7％。当观察钝化前后载流子寿命的变化时，我们将这种显着增强归因于去除了表面上的悬空键和氧化的氮化物（Ga-O或Al-O键）。因此，我们的结果突显了采用该工艺实现高性能纳米线UV发射器的可能性。当观察钝化前后载流子寿命的变化时，我们将这种显着增强归因于去除了表面上的悬空键和氧化的氮化物（Ga-O或Al-O键）。因此，我们的结果突显了采用该工艺实现高性能纳米线UV发射器的可能性。当观察钝化前后载流子寿命的变化时，我们将这种显着增强归因于去除了表面上的悬空键和氧化的氮化物（Ga-O或Al-O键）。因此，我们的结果突显了采用该工艺实现高性能纳米线UV发射器的可能性。