The Output Power Enhancements of GaN-Based Blue Light-Emitting Diodes with Highly Reflective Ag/Cr/Au Trilayer Omnidirectional Reflective Electrode Pads

Abstract

In this study, we demonstrated the fabrication of GaN-based light-emitting diodes (LEDs) on a patterned sapphire substrate (PSS) or non-PSS with nonalloy Ag/Cr/Au trilayer metal electrode pads on the exposed n+-GaN and indium tin oxide layers to be the n-type electrode and p-type electrode, respectively. The forward voltages of all LED samples at 20 mA were in the range of 3.1–3.2 V and were sufficiently low compared with those of commercial GaN-based LEDs. In the present experiment, the 20 mA output power of GaN-based LEDs with Ag/Cr/Au trilayer electrode bonding pads can be increased by a magnitude of 17% compared with those of the conventional LEDs with nonalloy Cr/Au bonding pads. Moreover, the 20 mA output power of GaN-based LEDs will be increased by more than 40 and 11% by introducing PSS and Ag/Cr/Au trilayer electrode bonding pads compared with those of the conventional LEDs and PSS LEDs, respectively, with nonalloy Cr/Au bonding pads.