GaN-Based LEDs on Nano-Patterned Sapphire Substrates

2011 ◽  
Vol 415-417 ◽  
pp. 656-659
Author(s):  
Jing Zhang ◽  
Shiro Sakai

We have successfully fabricated light emitting diodes (LEDs) based on patterned sapphire substrates (PSSs) fabricated by employing nanoimprint lithography (NIL) technique. The nano-patterns were designed as regular triangles consisting of columns, whose diameters and pitches were 100, 150, 200, 250 nm and 200, 300, 400, 500 nm, respectively. 412 nm wavelength LEDs grown by metal organic chemical vapor deposition (MOCVD) method were also demonstrated. The NIL technique and nano-etching by employing RIE were demonstrated in details. The qualities of all LEDs based on PSSs are superior compared with that non-patterned sapphire substrate LED. The experimental results showed that the light output power was increased by using the PSS structure. At a driving current of 20 mA, the light output powers of LEDs based on PSSs with 200, 300, 400 and 500 nm pitches are enhanced by 59%, 79%, 42% and 48%, compared with the conventional LEDs. These results provide promising potential to increase output powers of commercial light-emitting devices.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Sheng-Fu Yu ◽  
Sheng-Po Chang ◽  
Shoou-Jinn Chang ◽  
Ray-Ming Lin ◽  
Hsin-Hung Wu ◽  
...  

The optical and electrical characteristics of InGaN-based blue light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) with different pattern heights and on planar sapphire by atmospheric-pressure metal-organic chemical vapor deposition were investigated. Compared with planar sapphire, it was found that the LED electroluminescence intensity is significantly enhanced on PSSs with pattern heights of 0.5 (21%), 1.1 (57%), 1.5 (81%), and 1.9 (91%) μm at an injected current of 20 mA. The increased light intensity exhibits the same trend in a TracePro simulation. In addition, it was also found that the level of leakage current depends on the density of V-shape defects, which were measured by scanning electron microscopy.


2012 ◽  
Vol 1439 ◽  
pp. 109-114
Author(s):  
XinYi Chen ◽  
Alan M. C. Ng ◽  
Aleksandra B. Djurišić ◽  
Chi Chung Ling ◽  
Wai-Kin Chan ◽  
...  

ABSTRACTLight-emitting diodes (LEDs) based on p-GaN/ZnO heterojunction were fabricated. GaN was deposited on sapphire using metal-organic chemical vapor deposition (MOCVD), and two kinds of ZnO i.e. ZnO thin film deposited by sputtering and ZnO nanorods (NRs) grown by hydrothermal method were used as n-type layer respectively. MgO film with the thickness around 10 nm was deposited by electron-beam deposition to act as an interlayer between GaN and ZnO. Photoluminescence, electroluminescence and I-V curves were measured to compare the properties of GaN based heterojunction LEDs with different architectures. The existence of MgO interlayer as well as the morphology of ZnO obviously influenced the electrical and optical properties of GaN based LEDs. The effect of MgO interlayer on ZnO growth, properties and I-V curves and emission spectra of LEDs is discussed in detail.


2009 ◽  
Vol 94 (22) ◽  
pp. 222105 ◽  
Author(s):  
William E. Fenwick ◽  
Andrew Melton ◽  
Tianming Xu ◽  
Nola Li ◽  
Christopher Summers ◽  
...  

Nanoscale ◽  
2014 ◽  
Vol 6 (23) ◽  
pp. 14213-14220 ◽  
Author(s):  
Je-Hyung Kim ◽  
Young-Ho Ko ◽  
Jong-Hoi Cho ◽  
Su-Hyun Gong ◽  
Suk-Min Ko ◽  
...  

Broadband visible-light emitting GaN/InGaN core–shell nanostructures were demonstrated by a dislocation-eliminating chemical vapor-phase etching technique followed by metal–organic chemical vapor deposition.


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