Efficiency droop improvement in GaN-based light-emitting diodes by graded-composition electron blocking layer

Abstract

A graded-composition electron blocking layer (GEBL) with aluminum composition increasing along [ 0001] direction was designed for c-plane GaN-based light-emitting diodes (LEDs). The simulation results demonstrated that such GEBL can effectively enhance the capability of hole transportation across the EBL as well as the electron confinement. Consequently, the LED with GEBL grown by metal-organic chemical vapor deposition exhibited better electrical characteristics, and much higher output power at high current density, as compared to conventional LED. Meanwhile, the efficiency droop was reduced from 34% in conventional LED to only 4% from the maximum value at low injection current to 200 A/cm(2).