Enhanced Light Output of UVA GaN Vertical LEDs With Novel DBR Mirrors
Enhanced Light Output of UVA GaN Vertical LEDs With Novel DBR Mirrors
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DOI：
10.1109/jqe.2015.2502901
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发表时间：
2015-12-01
影响因子：
2.5
通讯作者：
Lu, Tien-Chang
中科院分区：
文献类型：
--
作者：
Kuo, Shiou-Yi;Hong, Kuo-Bin;Lu, Tien-Chang
当发射波长小于370 nm时，由于GaN层对发射光的吸收，GaN基发光二极管（led）的发射效率显著降低。垂直LED结构可以避免吸收问题，因为在制造过程中会去除未掺杂的GaN层，并且可以尽可能地薄化n-GaN层。在本报告中，我们提出了一种新的紫外（UV） LED结构，该结构采用薄的铟-二氧化铟（ITO）层作为欧姆接触，介质分布布拉格反射器（DBR）作为高反射率反射镜。比较ITO/Ag作为金属反射镜的垂直UV LED结构，ITO/DBR反射镜的垂直UV LED在350 mA时的输出功率约为190 mW，增强7.9%。
The emission efficiency of GaN-based light-emitting diodes (LEDs) decreases significantly as the emission wavelength is shorter than 370 nm because of the absorption of emission light in the GaN layers. The vertical LED structure could be applied to avoid the absorption problem, because the undoped GaN layer would be removed and the n-GaN layer could be thinned as much as possible in the fabrication process. In this report, we propose a novel ultraviolet (UV) LED structure with a thin indium-tinoxide (ITO) layer as the ohmic contact and a dielectric distributed Bragg reflector (DBR) as the high reflectivity mirror. Comparing referenced vertical UV LED structures with ITO/Ag as the metal mirror, the vertical UV LED with the ITO/DBR mirror shows the output power of approximately 190 mW at 350 mA with 7.9% enhancement.