Improvement of light extraction efficiency of 350‐nm emission UV light‐emitting diodes

In this study, we have aimed to improve the light extraction efficiency by using p- and n- high-reflectivity indium tin oxide (ITO)/Al electrodes with a reflectivity of ∼77% at 350 nm, laser lift-off (LLO) method, and silicone sealing. By a combination of these three methods, the light output power and operating voltage of UV LEDs were improved to 23.8 mW and 6.6 V at 100 mA. Furthermore, the external quantum efficiency and light extraction efficiency were improved to 6.6 and 25.3% at 100 mA. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)