Performance Enhancement of Ultraviolet Light-Emitting Diodes by Incorporating a Thin Al(In)GaN Interlayer in Multiquantum-Well Region

Abstract

In this paper, the performance improvement of 380-nm InGaN/AlGaN ultraviolet light-emitting diodes (UV-LEDs) is investigated by incorporating an undoped Al(In)GaN thin interlayer between the InGaN well and AlGaN barrier in multiquantum-well (MQW) active region. By inserting the graded-composition AlGaN and AlInGaN thin interlayers, the light output powers of UV-LEDs are significantly increased by 70% and 105% at 20 mA, respectively, as compared with the LED without the interlayer. Remarkable efficiency enhancement in the UV-LEDs with graded-composition AlGaN and AlInGaN interlayers is mainly attributed to the further improvement of the electron confinement and hole injection with more uniform distribution in the MQW active region. Besides, photoluminescence and atomic force microscope analyses indicate that the MQW quality can be enhanced by incorporating a graded-composition AlInGaN thin interlayer in the MQW active region of UV-LEDs.Index Terms-Ultraviolet light-emitting diode (UV-LED), multi-quantum-well (MQW), Al(In)GaN interlayer, photoluminescence (PL).

High-efficiency InGaN/AlInGaN multiple quantum wells with lattice-matched AlInGaN superlattices barrier

“…The Al x In y Ga 1−x−y N quaternary alloy system has attracted intense attention because its band gap and lattice constant is allowed to be independently adjusted by tuning Al or In composition. [1][2][3][4] Furthermore, owing to the higher thermal stability, using AlInGaN as the protection layer is effective to suppress the generation of non-radiative recombination centers in multiple quantum wells (MQWs) caused by thermal damage in the ramp-up process of metalorganic chemical vapor deposition (MOCVD). [5] Accordingly, AlInGaN is an ideal material for minimizing mismatch-induced strain and enhancing band offset in GaN-based heterostructure.…”

Performance optimization of AlGaN-based LEDs by use of ultraviolet-transparent indium tin oxide: Effect of in situ contact treatment

“…13,14) In particular, when ITO is used as an electrode, some researchers have also found that the interface dipole could be effectively modulated by performing interface treatment. 15) Finally, in order to make a comparison with previous research from other groups, 7,8,[16][17][18][19][20][21][22][23] the performance of UV LEDs fabricated with MOCVD-ITO TCEs is displayed in Fig. 5.…”