Design of electron blocking layers for improving internal quantum efficiency of InGaN/AlGaN-based ultraviolet light-emitting diodes.

In this paper, we designed and simulated InGaN/AlGaN-based near-ultraviolet light-emitting diode (NUV LED) epi-structures to obtain high internal quantum efficiency and low efficiency droop. When the conventional epi-structure of an $$\hbox {Al}_{0.1}\hbox {Gal}_{0.9}\hbox {N}$$ last quantum barrier and an $$\hbox {Al}_{0.21}\hbox {Gal}_{0.79}\hbox {N}$$ electron blocking layer (EBL) was replaced with a graded last quantum barrier and multi-step EBLs, the NUV LED showed 35 % higher internal quantum efficiency and 25 % more suppression of efficiency droop than the conventional NUV LED. Furthermore, a detailed study of the grading effect of the EBL revealed that 10-step EBLs increase performance when compared to other structures. These results are attributed to the polarization-induced effect, which reduces the electron leakage and increases the hole injection efficiency. [ABSTRACT FROM AUTHOR]