High-efficiency GaN-based LED with patterned SiO2 passivation layer and discontinuous current block layer

Abstract

GaN-based blue light-emitting diodes (LEDs) with patterned SiO2 passivation layer and discontinuous current block layer (CBL) has been proposed and fabricated. The patterned SiO2 passivation layer is inserted between Indium tin oxide (ITO) and P/N electrodes, and has a series of windows under the P and N electrodes, it can not only isolate the N electrode from the sidewall to prevent leakage, but also can re-contact the P electrode with ITO to form discontinuous P electrode structure and current injection. For the etching of active region, we use the method that partially etched to form a discontinuous N-GaN mesa, which can reduce the loss of the active area and improve the light emission intensity of the LEDs. It can be called discontinuous N-electrode structure. In addition, the discontinuous CBL deposited between P-GaN and ITO can increase the light extract efficiency from the active region under the P electrode compared to the conventional LED structure. As a result, at an injection current of 150mA, the light output power of the LED with patterned SiO2 passivation layer and discontinuous CBL was 7.06% higher than that of conventional structure LED. What’s more, at 50mA, the LED with the patterned SiO2 passivation layer and discontinuous CBL structure shows the lower forward voltage of 3.29V compared with the conventional LED of 3.41V.