Performance enhancement of yellow InGaN-based multiple-quantum-well light-emitting diodes grown on Si substrates by optimizing the InGaN/GaN superlattice interlayer

A specially designed InGaN/GaN superlattice (SL) interlayer was inserted between n-GaN and a multiple quantum well to enhance the performance of yellow light-emitting diodes (LEDs) grown on Si (111). The number of SL periods was determined to be the key to enhancing the external quantum efficiency and reducing forward voltage. Our results show that more SLs could suppress nonradiative recombination by eliminating micron-scale indium-rich clusters and could promote hole injection with increased V-pit size. However, too many SLs reduce the effective luminescence area and lead to many voids formed in the p-type layer. We demonstrate that 32 is the optimum number of SLs for yellow InGaN/GaN LEDs, obtaining a high light output power of 63 mW with a dominant wavelength of 568 nm, and a low forward voltage of 2.38 V at 200 mA (20 A/cm2).