Enhancing Light Emission of Nanostructured Vertical Light-Emitting Diodes by Minimizing Total Internal Reflection

被引：51

作者：

Ye, Byeong-Uk ^{[1
]}

Kim, Buem Joon ^{[2
]}

Song, Yang Hee ^{[2
]}

Son, Jun Ho ^{[2
]}

Yu, Hak Ki ^{[2
]}

Kim, Myung Hwa ^{[3
]}

Lee, Jong-Lam ^{[2
]}

Baik, Jeong Min ^{[1
]}

机构：

[1] UNIST, Sch Mech & Adv Mat Engn, Ulsan 689798, South Korea

[2] Pohang Univ Sci & Technol POSTECH, Dept Mat Sci & Engn, Div Adv Mat Sci, Pohang 790784, Gyeongbuk, South Korea

[3] Ewha Womans Univ, Dept Chem & Nano Sci, Seoul 120750, South Korea

来源：

ADVANCED FUNCTIONAL MATERIALS | 2012年 / 22卷 / 03期

基金：

新加坡国家研究基金会;

关键词：

ZnO nanorods; N-face; light-emitting diodes; light extraction efficiency; finite-difference time-domain; GAN; EXTRACTION; POLARITY; ENHANCEMENT; EFFICIENCY; GROWTH; FABRICATION; NANORODS; ARRAYS;

D O I：

10.1002/adfm.201101987

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Nanostructured vertical light-emitting diodes (V-LEDs) with a very dense forest of vertically aligned ZnO nanowires on the surface of N-face n-type GaN are reported with a dramatic improvement in light extraction efficiency (similar to 3.0x). The structural transformation (i.e., dissociation of the surface nitrogen atoms) at the nanolevel by the UV radiation and Ozone treatments contributes significantly to the initial nucleation for the nanowires growth due to the interdiffusion of Zn into GaN, evident by the scanning photoemission microscopy (SPEM), high-resolution transmission electron microscopy (HR-TEM), and ultraviolet photoelectron spectroscopy (UPS) measurements. This enables the growth of densely aligned ZnO nanowires on N-face n-type GaN. This approach shows an extreme enhancement in light extraction efficiency (>2.8x) compared to flat V-LEDs, in good agreement with the simulation expectations (similar to 3.01x) obtained from 3D finite-difference time-domain (FDTD) tools, explained by the wave-guiding effect. The further increase (similar to 30%) in light extraction efficiency is also observed by optimized design of nanogeometry (i.e., MgO layer on ZnO nanorods).

引用

页码：632 / 639

页数：8

共 29 条

[1] Morphology and polarity of GaN single crystals synthesized by the Na flux method [J].

Aoki, M ;

Yamane, H ;

Shimada, M ;

Kajiwara, T ;

Sarayama, S ;

DiSalvo, FJ .

CRYSTAL GROWTH & DESIGN, 2002, 2 (01) :55-58

[2] Tunable light extraction efficiency of GaN light emitting diodes by ZnO nanorod arrays [J].

Chao, C. H. ;

Lin, W. H. ;

Chen, C. H. ;

Changjean, C. H. ;

Lin, C. F. .

SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 2009, 24 (10)

[3] Enhancement of light output intensity by integrating ZnO nanorod arrays on GaN-based LLO vertical LEDs [J].

Chiu, C. H. ;

Lee, C. E. ;

Chao, C. L. ;

Cheng, B. S. ;

Huang, H. W. ;

Kuo, H. C. ;

Lu, T. C. ;

Wang, S. C. ;

Kuo, W. L. ;

Hsiao, C. S. ;

Chen, S. Y. .

ELECTROCHEMICAL AND SOLID STATE LETTERS, 2008, 11 (04) :H84-H87

[4] Influence of the alignment of ZnO nanorod arrays on light extraction enhancement of GaN-based light-emitting diodes [J].

Dai, Kehui ;

Soh, Chew Beng ;

Chua, Soo Jin ;

Wang, Lianshan ;

Huang, Dexiu .

JOURNAL OF APPLIED PHYSICS, 2011, 109 (08)

[5] Optimization scheme for the quantum efficiency of GaInN-based green-light-emitting diodes - art. no. 071105 [J].

Fuhrmann, D ;

Netzel, C ;

Rossow, U ;

Hangleiter, A ;

Ade, G ;

Hinze, P .

APPLIED PHYSICS LETTERS, 2006, 88 (07)

[6] Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening [J].

Fujii, T ;

Gao, Y ;

Sharma, R ;

Hu, EL ;

DenBaars, SP ;

Nakamura, S .

APPLIED PHYSICS LETTERS, 2004, 84 (06) :855-857

[7] Control of crystal polarity in a wurtzite crystal: ZnO films grown by plasma-assisted molecular-beam epitaxy on GaN [J].

Hong, SK ;

Hanada, T ;

Ko, HJ ;

Chen, YF ;

Yao, T ;

Imai, D ;

Araki, K ;

Shinohara, M ;

Saitoh, K ;

Terauchi, M .

PHYSICAL REVIEW B, 2002, 65 (11) :1-10

[8] The role of reflective p-contacts in the enhancement of light extraction in nanotextured vertical InGaN light-emitting diodes [J].

Jang, Ho Won ;

Ryu, Seong Wook ;

Yu, Hak Ki ;

Lee, Sanghan ;

Lee, Jong-Lam .

NANOTECHNOLOGY, 2010, 21 (02)

[9] Recent Progress in GaN-Based Light-Emitting Diodes [J].

Jia, Haiqiang ;

Guo, Liwei ;

Wang, Wenxin ;

Chen, Hong .

ADVANCED MATERIALS, 2009, 21 (45) :4641-4646

[10]

Kim HM, 2002, ADV MATER, V14, P991, DOI 10.1002/1521-4095(20020705)14:13/14<991::AID-ADMA991>3.0.CO

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