Improvement in the Light Output Power of GaN-Based Light-Emitting Diodes by Natural-Cluster Silicon Dioxide Nanoparticles as the Current-Blocking Layer
In this study, the fabrication and characterization of InGaN-GaN multiple-quantum-well light-emitting diodes (LEDs) with silicon dioxide (SiO2) nanoparticles as the current-blocking layer (CBL) are described. The performance was improved by introducing SiO2 nanoparticles, not deposited by commonly used plasma-enhanced chemical vapor deposition, as the CBL beneath the p-pad. The injected current was forced to spread outside instead of flowing directly downward. At 20 mA, the light output power of the LED with a CBL was increased 15.7% as compared to that of the conventional LED. The forward voltage of the LED with the SiO2 nanoparticle CBL was 3.34 V at 20 mA, which was slightly higher than that of the conventional LED (3.29 V). The increase in the light output power can be attributed to the injection of additional current into the light-emitting active layer of the LED by the SiO2 nanoparticles CBL and thus a reduction in optical absorption at the p-pad.