Luminescence efficiency of InGaN multiple-quantum-well ultraviolet light-emitting diodes

摘要

The electroluminescence efficiency of In_(0.06)Ga_(0.94)N/GaN multiple-quantum-well UV light-emitting diodes (LEDs) with emission wavelength of 400 nm has been investigated and compared with blue (470 nm) LEDs. Based on their injection current-dependent characteristics under dc and pulsed operation, it can be concluded that carrier overflow is the dominant factor that affects the external quantum efficiency of UV LED before thermal effects take over. It is experimentally shown that increasing the number of quantum wells is necessary to alleviate the carrier overflow issue and improve the luminescence efficiency of the UV LEDs.