Controlled bunching approach for achieving high efficiency active region in AlGaN-based deep ultraviolet light-emitting devices with dual-band emission

Developing efficient active region structures with low sensitivity to threading dislocation density (TDD) is of great technical significance for AlGaN-based deep ultraviolet (DUV) light-emitting devices. Here, we propose an active region strategy by introducing bunching effect to form self-assembled sidewall quantum wells (SQWs) with much stronger carrier confinement, resulting in a significant enhancement of internal quantum efficiency (from 46% to 59%) compared to the commonly adopted multiple quantum wells (MQWs) due to the lower sensitivity to TDD. As a demo, an AlGaN-based DUV light-emitting diode (LED) with the proposed active region involving both SQWs and MQWs presents dual-band emission and a consequent 68% enhancement in light output power compared to the DUV-LED with only MQWs as the active region, suggesting that the proposed architecture is fully suitable for the development of high performance DUV light-emitting devices even based on poor or medium quality materials.