Heat-resistant reflectors for enhanced 850-nm near infrared light-emitting diode efficiency

Abstract

This study investigated the use of heat-resistive reflectors to improve the efficiency of wafer-bonded reflective 850 nm infrared light-emitting diodes (LEDs). The Au-based heat-resistive reflectors were synthesized with added Ni, Ti, Cu, and Al, and heat treated at 450 °C. The Al/Au alloyed reflector exhibited the highest reflectivity of nearly 90% when incorporated into the wafer-bonded epi-layer (Al0.3Ga0.7As/GaP). Further, the output power of 850 nm LED chips based on the pure Au and alloyed reflectors were compared, where the Al/Au alloyed reflector led to a 1.4-fold increase in output power compared to the pure Au reflector. This increase is attributed to enhanced heat-resistant reflectivity of the Al/Au alloyed reflector. Therefore, the Al/Au alloyed reflector shows promise for the development of more efficient reflective infrared LEDs.