The AlGaN-based deep ultraviolet[DUV]light-emitting diode[LED]is an alternative DUV light source to replace traditional mercury-based lamps.However,the state-of-the-art DUV LEDs currently exhibit poor wall-plug efficiency and low light output power,which seriously hinder their commercialization.In this work,we design and report a tunnel-junction-cascaded[TJC]DUV LED,which enables multiple radiative recombinations within the active regions.Therefore,the light output power of the TJC-DUV LEDs is more than doubled compared to the conventional DUV LED.Correspondingly,the wall-plug efficiency of the TJC-DUV LED is also significantly boosted by 25％ at 60 mA.