The reduction of efficiency droop by Al _0.82In _0.18N/GaN superlattice electron blocking layer in (0001) oriented GaN-based light emitting diodes

To investigate the effect of Al _0.82In _0.18N electron blocking layer (EBL) on the efficiency droop, (0001) oriented InGaN light emitting diodes (LEDs) were grown with two different types of EBLs-single Al _0.82In _0.18N:Mg layer and Al _0.82In _0.18N:Mg (2 nm)/GaN:Mg (2 nm) superlattice (SL) structure with 7 periods. It was found that the output power and operating voltage of single Al _0.82In _0.18N EBL LED were sensitive to EBL thickness due to the difficulty in growing high quality Mg doped Al _0.82In _0.18N. On the other hand, LED with SL EBL showed no deterioration of optical power and operating voltage while its efficiency droop (17 at 300 A/cm ²) reduced by more than a half compared to a conventional Al _0.2Ga _0.8N (20 nm) EBL LED (36 at 300 A/cm ²).