Efficient Carrier Transport for AlGaN-Based Deep-UV LEDs With Graded Superlattice p-AlGaN

In this article, a novel graded superlattice (SL) p-AlGaN structure for deep ultraviolet light-emitting diode (DUV LED) capable of emitting 273 nm has been studied. It is observed that the output power in the case of graded SL p-AlGaN LED structure (GSLED) is significantly high (7.68-fold higher, at the current density of 200 A/cm
²
) compared with a conventional structure. Moreover, noticeable improvements in the maximum value of external quantum efficiency, as well as the efficiency droop, are achieved with the modified structures. The abrupt potential barrier height in conventional DUV LED (CLED) obstructs the hole injection inside the quantum well region. On the contrary, smoother band variation in GSLED prevents potential barrier height of hole and causes ease in the flow of hole into the quantum well (QW) region. Also, the electron concentration in the multiple-quantum-well (MQW) region for GSLED is increased by around 100% due to the reduced leakage of electrons toward the p-region.