1. EBL Structure 1

2. N-EBL Barrier Well Al0.17Ga0.83 Al0.25Ga0.75 Al0.17Ga0.83 Structure 1 2

3. Well P-EBL P-Barrier Structure 2 3 P-Barrier

4. Well P-EBL P-Barrier N-EBL Structure 3 4 P-Barrier

5. p-GaN p-EBL GaN InGaN 20nm Al 0.2 Ga 0.8 N 2nm Al 0.05 Ga 0.95 N Structure 4 5

6. n-GaN Superlattice n-EBLAl 0.1 Ga 0.9 N/GaN 3nm/1nm 5pair MQW Al 0.2 Ga 0.8 N 5nm Structure 5 6

7. p-GaN p-EBL GaN InGaN 20nm Al 含量 0%~25%~0% Structure 6 7

8. p-GaNn-GaN p-AlGaN MQW(GaN/InGaN) Original structure p-GaN n-GaN p-AlGaN MQW(GaN/InGaN) New structure 透過在 MQW 與 EBL 間插入一 層 AlGaN superlattice ，做為 緩衝 last barrier 與 EBL lattice mismatch 所帶來能帶傾斜的 效應 !! 進而增加 EBL 有效的能 障高度 … Structure 7 8

9. p-GaN n-GaN p-AlGaN MQW(GaN/InGaN) Original structure 在 last barrier 做一 n 參雜，目的在於 形成一空乏區內建電場 ! 透過 PN 面 空乏區電場來去抵補極化場 !! n-GaN New structure p-GaN p-type n-type Structure 8 9

10. 極化場方向 內建電場方向 10

11. p-GaN n-GaN p-AlGaN MQW(GaN/InGaN) Original structure n-GaN New structure Ap-type MQW(InGaN/InGaN) Graded-GaN InGaN barrier GaN +last barrier EBL 在 QW 中使用 InGaN/InGaN, 增 加晶格與晶格間的長晶匹配 並在最後 Last barrier 處 做一 GaN 的能帶調變，目的在改 善與最後的 Al-GaN 晶格 missmatch!! 藉此改善 晶格間 的極化效應。 Structure 9 11

12. n-GaN New structure Bp-type MQW(InGaN/InGaN) Graded P-GaN InGaN barrier P-GaN +last barrier EBL 12

13. n-GaN New structure Cp-type MQW(InGaN/InGaN) Graded P-GaN InGaN barrier P-GaN +last barrier EBL SuperLattice 13

14. Reference Effect of N-Type AlGaN Layer on Carrier Transportation and Efficiency Droop of Blue InGaN Light-Emitting Diodes Sheng-Horng Yen, Miao-Chan Tsai, Meng-Lun Tsai, Yu-Jiun Shen, Ta-Cheng Hsu, and Yen-Kuang KuoIEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 21, NO. 14, JULY 15, 2009 975 Efficiency enhancement in ultraviolet light-emitting diodes by manipulating polarization effect in electron blocking layer Yu-Hsuan Lu, Yi-Keng Fu, Shyh-Jer Huang, Yan-Kuin Su, Rong Xuan et al. Enhancing the performance of green GaN-based light-emitting diodes with graded superlattice AlGaN/GaN inserting layer Junjie Kang, Hongjian Li, Zhi Li, Zhiqiang Liu, Ping Ma, Xiaoyan Yi, and Guohong Wang 14

15. Thanks for your attention