Design of Hole-Blocking and Electron-Blocking Layers in AlxGa1-xN-Based UV Light-Emitting Diodes

• Published in: IEEE transactions on electron devices Vol. 63; no. 3; pp. 1141 - 1147
• Main Authors: Ya-Hsuan Shih, Jih-Yuan Chang, Jinn-Kong Sheu, Yen-Kuang Kuo, Fang-Ming Chen, Ming-Lun Lee, Wei-Chih Lai
• Format: Journal Article
• Language: English
• Published: IEEE 01.03.2016
• Subjects: Charge carrier processes; Current density; Electron-blocking layer (EBL); hole-blocking layer (HBL); Leakage currents; Light emitting diodes; light-emitting diodes (LEDs); Photonic band gap; Power generation; Simulation; ultraviolet (UV); ultraviolet (UV); hole-blocking layer (HBL); Electron-blocking layer (EBL); light-emitting diodes (LEDs)
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2016.2520998

The band-engineered structure design for electron-blocking layer (EBL) and hole-blocking layer (HBL) in Al x Ga 1-x N-based ultraviolet light-emitting diodes (UV LEDs) is performed and analyzed theoretically. Simulation results show that the severe polarization effect is efficiently mitigated and the downward-bended band profile of the EBL is improved when the EBL is designed with a graded-composition and multiquantum barrier (GMQB) structure. As a result, the capabilities of both electron confinement and hole injection, and also the light output power are promoted. On the contrary, for the HBL, the design of composition graded and/or multiquantum barrier structures reduces the effective potential barrier height for holes in the valence band and, consequently, causes a considerable hole overflow. The UV LED, thus, exhibits superior optical performance when the LED structure is simultaneously designed with a GMQB EBL and a bulk HBL.