Reduced Droop Effect in Nitride Light Emitting Diodes With Taper-Shaped Electron Blocking Layer

A taper-shaped AlGaN electron blocking layer (TEBL) has been designed and incorporated in InGaN/GaN light emitting diodes (LEDs) to promote hole injection and electron confinement under high current injection conditions. Fabricated LEDs with a TEBL exhibit reduced operating voltage, enhanced efficiency as well as alleviated droop effect, compared with those with a conventional bulk AlGaN EBL. The improvement is due to improved electron confinement and hole transportation as well as decreased electrostatic fields in the active region.