Performance Enhancement of Blue Light-Emitting Diodes Without an Electron-Blocking Layer by Using p-Type Doped Barriers and a Hole-Blocking Layer of Low Al Mole Fraction

In this paper, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL. The simulation results also show that the LED without an EBL has severe efficiency droop. However, when the p-type doped QW barriers and a hole-blocking layer are used, the efficiency droop is markedly improved and the electroluminescence emission intensity is greatly enhanced.