High efficiency improvements in AlGaN-based ultraviolet light-emitting diodes with specially designed AlGaN superlattice hole and electron blocking layers. (April 2017)

• Record Type: Journal Article
• Authors: Yi, Xinyan; Sun, Huiqing; Sun, Jie; Yang, Xian; Fan, Xuancong; Zhang, Zhuding; Guo, Zhiyou
• Is Part Of: Superlattices and microstructures. Volume 104(2017)
• Page Start: 19
• Page End: 23
• Publication Date: 2017-04
• Subjects: AlGaN -- UVLED -- Graded superlattice hole blocking layers -- Graded superlattice electron blocking layers -- IQE; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2017.01.042
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: Alx Ga1-x N/Al0.6 Ga0.4 N graded superlattice hole blocking layers (GSL-HBLs) and Alx Ga1-x N/Al0.6 Ga0.4 N graded superlattice electron blocking layers (GSL-EBLs) are applied to the traditional AlGaN-based ultraviolet light-emitting diodes (UVLEDs). This can obtain much higher internal quantum efficiency (IQE) and output power. In order to reveal the underlying physical mechanism of this unique structure, we have studied it numerically by APSYS simulation programs. We find that GSL-EBLs can obviously increase the electron potential height and reduce the hole potential height, produce less electron leakage and more hole injection, leading to higher carrier contration. GSL-HBLs can obviously reduce the hole leakage, reduce the thermal velocity and correspondingly the mean free path of the hot electrons, and increase the electron injection. This enhanced the electron capture efficiency of the multiple quantum wells, which can also help to reduce electron leakage. Highlights: Our specially designed AlGaN graded superlattice hole and electron blocking layers can enhance the rad recombination. AlGaN-based UVLEDs with four different new structures are compared in detail. Different combination of GSL-HBL and GSL-EBL has different effect. The combination of GSL-HBL and GSL-EBL, which likes the dam and conforms to the principle of the dam, has the optimal results. The root of efficiency improvements has been explored.