Performance Enhancement of Blue Light-Emitting Diodes With an Undoped AlGaN Electron-Blocking Layer in the Active Region

Optical performances of blue InGaN light-emitting diodes (LEDs) with an undoped AlGaN electron-blocking layer (U-AlGaN EBL) embedded in the active region are investigated numerically. As a benefit of this special structural design, the electrons would spill over the EBL and recombine with the holes in the wells close to the p-side. Moreover, holes in the wells that are close to the n-side increase to a higher concentration due to the presence of a new shallow potential well in the valence band. The simulation results indicate that the LEDs with U-AlGaN EBL has higher internal quantum efficiency as well as light output power compared with the conventional single p-type AlGaN EBL structure. These improvements are primarily contributed to the enhancement on electrons confinement and holes injection.