Controlled bunching approach for achieving high efficiency active region in AlGaN-based deep ultraviolet light-emitting devices with dual-band emission
Yong Sun, Fujun Xu, Nan Xie, Junmei Wang, N. Zhang, Jing Lang, B. Y. Liu, Xuzhou Fang, L. B. Wang, Weikun Ge, Xuanwu Kang, Z. X. Qin, Xuelin Yang, Xinqiang Wang, Bo Shen
Abstract
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.