“…Extensive works had been reported on achieving high internal quantum efficiency (IQE) in LEDs by using QW designs that can address the charge separation issues. The related representative QW designs include semi/non-polar InGaN QWs [1], [2] and polar QWs structures with large electron-hole wavefunction overlap such as (1) Staggered QW [3]- [8], (2) Type-II QW [9]- [11], (3) InGaN-delta-AlGaN QW [12], [13], (4) InGaN-delta-InN QW [14], and (5) Strain-compensated QW [15], [16]. On the other hand, the efficiency droop effect caused by carrier leakage (thermionic carrier leakage and polarization-induced leakage) [17]- [20] and/or Auger processes [21]- [23], which strongly limits the QE and hampers the further development of nitride-based LEDs, has been widely reported.…”