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 SiO 2 passivation layer and discontinuous current block layer (CBL) has been proposed and fabricated. The patterned SiO 2 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 SiO 2 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 SiO 2 passivation layer and discontinuous CBL structure shows the lower forward voltage of 3.29V compared with the conventional LED of 3.41V.