Monolithic Dual-Wavelength AlGaN-Based UV-LEDs with Controllable Spectral Profile

Ultraviolet (UV) light sources with multiple wavelength emissions have many applications in different scenarios. However, there are rare reports on multiwavelength UV light-emitting diodes (LEDs). In this paper, through adopting dual-wavelength multiple quantum wells (MQWs) with a specific structure of an ultrathin AlGaN single quantum well (SQW) with emission at the UVC range grown on MQWs with emission at the UVB range, we fabricate a UV-LED with simultaneous emission at wavelengths of 278 and 307 nm. This dual-wavelength UV-LED exhibits a high wall-plug efficiency (WPE) of 3.86% under an operating current of 10 mA and demonstrates an impressive spectral stability with increasing current from 10 to 100 mA. Furthermore, we are able to manipulate the emission spectral profile of the dual-wavelength UV-LEDs by adjusting the thickness of the barrier between the UVC SQW and the UVB MQWs. This high-performance dual-wavelength UV-LED fabricated on an integrated monolithic chip with stable and controllable spectral characteristics is useful for expanding the applications of compact AlGaN-based UV-LEDs.