Improvement in light-output efficiency of InGaN/GaN multiple-quantum well light-emitting diodes by current blocking layer

The fabrication and characterization of an InGaN/GaN multiple-quantum well (MQW) light-emitting diode (LED) with a SiO2 current blocking layer inserted beneath the p-pad electrode is described. The light-output power and external quantum efficiency for the InGaN/GaN MQW LED chip with a current blocking layer were significantly increased compared to those for the conventional InGaN/GaN MQW LED chip. The increase in the light-output power can be attributed to the injection of additional current into the light-emitting quantum well layer of the LED by the SiO2 current blocking layer and a reduction in parasitic optical absorption in the p-pad electrode.