Improving hole injection with the polarization effect for 279 nm AlGaN-based deep ultraviolet light-emitting diodes

It is commonly known that the high ionization energy of acceptor magnesium is the cause of the low hole injection efficiency in the active region of AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs). This study presents an effective method of exploiting the polarization effect in quantum wells to increase the hole injection efficiency of 279 nm AlGaN-based DUV LEDs. The polarization electric field can be exploited to increase the mean free path of holes and improve hole concentration in the active region by suitably increasing the thickness of the quantum well. This method effectively increases the hole concentration and improves the electron-hole wave function overlap. As a result, the internal quantum efficiency and optical power of DUV LEDs are significantly enhanced. It is noteworthy that the strong quantum confined stark effect can cause electron and hole wave functions to separate, leading to a decrease in LED performance when quantum wells exceed a certain thickness.