Improved carrier transport and photoelectric properties of InGaN/GaN multiple quantum wells with wider well and narrower barrier

Abstract

Band alignment of InGaN/GaN multiple quantum wells (MQW) light-emitting diode was investigated by regulating the widths of well and barrier. Novel structure of InGaN/GaN MQW was designed with wider well and narrower barrier with respect to conventional InGaN/GaN MQW with the layer thickness of 2.5/12.5 nm, respectively. The analyses of band alignment, and hole and electron concentrations within the MQW zone show that the novel MQW structure could improve hole transport and block electron leakage owing to the increased potential barrier for electron and the decreased potential barrier for hole in MQW zone, as can be confirmed by decreased electron density and increased hole density. Both the intensity of electroluminescence and internal quantum efficiency for novel MQW are enhanced by increasing radiative recombination. Moreover, it was found that non-radiative recombination current density mainly stems from Auger recombination current density that mainly depends on excess electron. The novel MQW structure reduces built-in field at well/barrier interface owing to increased hole injection. This work provides an effective approach for achieving high performance for InGaN/GaN LED by regulating band offset.