López-Fraguas Eduardo, Binkowski Felix, Burger Sven, Hagedorn Sylvia, García-Cámara Braulio, Vergaz Ricardo, Becker Christiane, Manley Phillip
GDAF-UC3M, Dep. Tecnología Electrónica, Universidad Carlos III de Madrid, Avda. Universidad, 30., 28911, Leganés, Madrid, Spain.
Zuse Institute Berlin, Berlin, Takustraße 7, 14195, Berlin, Germany.
Sci Rep. 2022 Jul 7;12(1):11480. doi: 10.1038/s41598-022-15499-7.
Despite a wide array of applications, deep ultra-violet light emitting diodes offer relatively poor efficiencies compared to their optical counterparts. A contributing factor is the lower light extraction efficiency due to both highly absorbing p-contacts and total internal reflection. Here, we propose a structure consisting of a hexagonal periodic array of cylindrical nanoholes in the multi-layered p-contact which are filled with platinum. This nanostructure reduces the absorption of the p-contact layer, leading to a higher emission into the n-contact compared to a planar reference. An optimum geometry of the nanostructure allows a light extraction efficiency of 15.0%, much higher than the typical 4.6% of a planar reference. While the nanostructure strongly decreases the light absorption in the p-contact, it is still not able to considerably reduce the total internal reflection. Consequently, the nanostructured p-contact should be combined with other optical strategies, such as nanopatterned sapphire substrates to increase the efficiency even further. Despite this, the nanostructure described in this work provides a readily realizable path to enhancing the light extraction efficiency of state-of-the-art deep ultra-violet light emitting diodes.
尽管深紫外发光二极管有广泛的应用，但与光学同类产品相比，其效率相对较低。一个促成因素是由于高吸收性的p型接触层和全内反射导致的光提取效率较低。在此，我们提出一种结构，该结构由多层p型接触层中填充铂的圆柱形纳米孔的六边形周期性阵列组成。这种纳米结构减少了p型接触层的吸收，与平面参考相比，导致向n型接触的发射更高。纳米结构的最佳几何形状允许光提取效率达到15.0%，远高于平面参考的典型4.6%。虽然纳米结构强烈降低了p型接触层中的光吸收，但它仍然无法显著减少全内反射。因此，纳米结构化的p型接触层应与其他光学策略相结合，如纳米图案化蓝宝石衬底，以进一步提高效率。尽管如此，本文所述的纳米结构为提高先进深紫外发光二极管的光提取效率提供了一条易于实现的途径。
