Current blocking layer in GaN light-emitting diode

InGaN/GaN multiple-quantum well (MQW) light-emitting diode (LED) was fabricated using a SiO2 current blocking layer (CBL) inserted underneath the p-pad electrode. The forward voltage, V-F at 20 mA for InGaN/GaN MQW LED with a CBL (V-F= 3.5 V) was slightly higher than that of the conventional InGaN/GaN MQW LED (V-F= 3.4 V) due to the reduction in the total area of p-type metal contact between the transparent Pt layer and the p-GaN. However, the light-output power for InGaN/GaN MQW LED with a CBL at 20 mA was significantly increased by 62 % compared to that for the conventional InGaN/GaN MQW LED structure. This increase in the light-output power can be attributed to the more amount of current injected into the active area of the LED through the light-transmitting metal layer and a reduced parasitic optical absorption in the p-pad electrode.