Enhanced performance of GaN-based thin-film flip-chip LEDs with reflective current blocking layers

Abstract

To further enhance the performance of GaN-based thin-film flip-chip light-emitting diodes (TFFC-LEDs), we designed and fabricated two sets of high-power blue chips with conventional and reflective current-blocking layers (CBL) The conventional CBL is composed of SiO2, whereas the reflective CBL consists of SiO2 and a distributed Bragg reflector (DBR). We systematically characterized their optoelectronic performance. The results indicate that at an injection current of 350 mA, the light output power (LOP) and external quantum efficiency (EQE) of the TFFC-LEDs with a reflective CBL increased by 4.9% and 5.7%, respectively, compared to the chips with a conventional CBL. The TFCalc simulation results indicate that the reflectivity of the reflective CBL reached 99.15%. The TracePro simulation results demonstrate that the reflective CBL can effectively enhance the light-extraction performance of the chip. We believe that the reflective CBL structure provides significant guidance for the fabrication of high-efficiency LEDs.