Integrating remote reflector and air cavity into inclined sidewalls to enhance the light extraction efficiency for AlGaN-based DUV LEDs

In this work, we propose and demonstrate the concept of remote reflections, which help to multiply the photon propagations for increasing the light extraction efficiency (LEE) for both transverse magnetic (TM)- and transverse electric (TE)-polarized light. The remote reflection is enabled by using a remote-metal-reflector-based air cavity extractor. According to our study, the remote reflections can significantly avoid the optical absorption when compared with the conventional inclined-sidewall-shaped deep-ultraviolet light-emitting diodes with the metal Al reflector on the inclined sidewalls. As a result, the optical power for our proposed devices has been significantly enhanced by 55% experimentally. Numerical simulations further reveal that the remote metal reflector not only favors more total internal refection on the inclined sidewalls but also supports additional light escaped channels for enhancing the LEE.