230-nm-wavelength range far-UVC LED with low Al-composition differentiation between well and barrier layers of MQWs

Abstract

Reducing the average Al composition of AlxGa1−xN/AlyGa1−yN multiple quantum wells (MQWs) is an effective approach to increase the current injection efficiencies of far-ultraviolet-C light-emitting diodes (far-UVC LEDs). A reduction can be realized by decreasing the Al-composition differentiation between the well and barrier layers. Compared to conventional MQWs, a 230-nm-wavelength far-UVC LED equipped with a single-Al-composition and a 50-nm-thick light-emitting layer exhibits a higher external quantum efficiency (EQE). The EQE of far-UVC LEDs with low Al-composition differentiation (~1%) is enhanced to approximately 0.6% and 1.4% under continuous wave operations at 230 nm and 236 nm wavelengths, respectively.