1

EBL Structure

2

N-EBL

Barrier

Well

Al0.17Ga0.83 Al0.25Ga0.75 Al0.17Ga0.83

Structure 1

3

Well

P-EBL

P-Barrier

Structure 2

P-Barrier P-Barrier

4

Well

P-EBL

P-BarrierN-EBL

Structure 3

P-Barrier P-Barrier

5

p-GaN

p-EBL

GaNInGaN

20nm Al0.2Ga0.8N

2nm Al0.05Ga0.95N

Structure 4

6

n-GaN

Superlattice n-EBL Al0.1Ga0.9N/GaN3nm/1nm 5pair

MQW

Al0.2Ga0.8N 5nmStructure 5

7

p-GaN

p-EBL

GaNInGaN

20nm Al 含量 0%~25%~0%

Structure 6

8

p-GaNn-GaN

p-AlGaN

MQW(GaN/InGaN)

Original structure

p-GaNn-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

9

p-GaNn-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

10

極化場方向

內建電場方向

11

p-GaNn-GaN

p-AlGaN

MQW(GaN/InGaN)

Original structure

n-GaN

New structure A p-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

12

n-GaN

New structure B p-type

MQW(InGaN/InGaN)

Graded P-GaN

InGaN barrier

P-GaN+last barrier

EBL

13

n-GaN

New structure C p-type

MQW(InGaN/InGaN)

Graded P-GaN

InGaN barrier

P-GaN+last barrier

EBL

SuperLattice

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

Thanks for your attention