Enhancement of Output Power for GaN-Based LEDs by Treatments of Ar Plasma on p-GaN Surface

We successfully demonstrated that the Arplasmatreatment p-GaN surface increased the contact resistance of ITO/P-GaN serving as injection current deflection layer under the electrode pad. It was found that the V-f values of the two LEDs at 20 mA were approximately 3.3 V. Under a 20 mA current injection, it was found that output powers of conventional LED and Ar-plasma-treatment LED on p-GaN surfaces were 9.8 and 11.08 mW, respectively. We can increase the output power of GaN LEDs in 13% due to current blocking on the surface of p-GaN under the electrode pad by inserting the treatment with Ar plasma. It was also found that, after the reliability test for 72 hours the half lifetimes of conventional LEDs and LEDs with Ar-plasma treatment on p-GaN surface were about 49% and 55%, corresponding to the initial intensity, respectively.