Efficient InGaN-Based Red Light-Emitting Diodes by Modulating Trench Defects

Trench defects in multi-quantum wells (MQWs) have been considered as flawed structures that severely degraded the internal quantum efficiency (IQE) of light-emitting diodes (LEDs) in the past. In this research, trench defects are innovatively utilized to enhance the efficiency of red InGaN LEDs. Specifically, dual-color MQWs structures are applied to modulate trench defects. The upper red MQWs, grown on top of green MQWs with a high density of trench defects, exhibit a significant wavelength redshift of 68 nm and approximate to 6-fold luminescence enhancement compared to those without intentionally introduced trench defects. Red InGaN LEDs with an IQE of 16.4% are achieved with this epitaxy growth strategy. Such wavelength redshift is attributed to the more indium incorporation due to the strain relaxation effect of trench defects. Moreover, the luminescence enhancement originates from the strong emission of the red MQWs inside trench defects, mainly attributed to strain relaxation and defect shielding by the wide and deep trenches. Achieving red emission by modulating trench defects is simple and reproducible without requiring additional substrate designs, which provides a novel way toward high-efficiency red InGaN LEDs. Trench defects have been innovatively utilized to achieve high-efficiency InGaN-based red light-emitting diodes (LEDs). The red quantum wells exhibit significant luminescence enhancement and wavelength redshift by appropriately modulating the trench defects. Red InGaN LEDs with an internal quantum efficiency of 16.4% are achieved by this method.image