Efficiency improvements in AlGaN-based deep ultraviolet light-emitting diodes using inverted-V-shaped graded Al composition electron blocking layer. (December 2015)

• Record Type: Journal Article
• Authors: Fan, Xuancong; Sun, Huiqing; Li, Xuna; Sun, Hao; Zhang, Cheng; Zhang, Zhuding; Guo, Zhiyou
• Is Part Of: Superlattices and microstructures. Volume 88(2015)
• Page Start: 467
• Page End: 473
• Publication Date: 2015-12
• Subjects: Electron blocking layer -- Deep ultraviolet light-emitting diodes -- AlGaN; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2015.10.003
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: This paper principally presents the numerical investigation of electron blocking layers (EBL) structures with different Al concentration gradient changing in AlGaN-based deep ultraviolet light emitting diodes (DUV-LEDs). Compared to conventional EBL structure with constant Al composition, the LED with inverted-V-shaped EBL structure has higher output power and carriers recombination rate, but the efficiency droop will decrease obviously while the electron leakage current can reduce much as well. Therefore, the result indicates that appropriate Al component in LED can enhance electron and hole recombination rate in the active region. The improved performance is mainly attribute the sufficient electron-barrier height and relatively higher hole injection efficiency which results from the mitigated band-bending. Highlights: Four different EBL structure LEDs with different Al composition are compared in detail. EBL with graded Al component can enhance light output power and spontaneous emission. The relation of electrostatic field with band-bending is explained. Inverted-V-shaped EBL increases the efficiency of electron blocking and hole injection.