Improvement of reliability of GaN-based light-emitting diodes by selective wet etching with p-GaN

In an attempt to enhance the reliability of GaN-based light-emitting diodes (LEDs), the selective wet chemical etching of p-GaN surface in the GaN-based LEDs using KOH+ NaOH in an ethylene glycol solution was investigated. The leakage currents of the etched LED under forward and reverse bias voltages were much lower, compared to those of a nonetched LED. The etched LED also showed improved light extraction efficiency and the degradation rate of light output power at a high injection current of 300 mA was slower than that for a nonetched LED. These results can be attributed to a decrease in the surface defects, an increase in hole concentration, and the increased surface roughness of the etched p-GaN.