Structure design for light‐extraction enhancement of UVC‐LED

Abstract

UVC‐LEDs have drawn attention recently because of their benefits to sterilization, decontamination, etc. Since the internal quantum efficiency and light extraction efficiency (LEE) of UVC‐LEDs are low, their external quantum efficiency remains unsatisfied. To enhance the LEE, this study proposes an integration design with the features of substrate‐thickness optimization, substrate shaping, diffuse‐reflective coating, an index‐matching layer, and taper‐base optimization. In addition to optical modeling via ray tracing, thermal modeling is conducted to evaluate both the optical and thermal performances of each feature. The simulation results show that, by means of the combination of these features, the LEE of the chip can be raised from 18.5% to more than 40%, and the average temperature of the device can be lowered by 2.2°C via the design of the diffuse‐reflective coating.