Enhanced wavelength-selective photoresponsivity with a MoS2 bilayer grown conformally on a patterned sapphire substrate

2019 ◽  
Vol 7 (6) ◽  
pp. 1622-1629 ◽  
Author(s):  
Sung-Wen Huang Chen ◽  
Sheng-Wen Wang ◽  
Kuo-Bin Hong ◽  
Henry Medin ◽  
Chieh-Han Chung ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Simple Method ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

Wavelength-selective photodetectors with a MoS2 bilayer on patterned sapphire substrates have been demonstrated using a facile and simple method.

scholarly journals Suppressing the Initial Growth of Sidewall GaN by Modifying Micron-Sized Patterned Sapphire Substrate with H3PO4-Based Etchant

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 622 ◽  
Author(s):  
Wen-Yang Hsu ◽  
Yuan-Chi Lian ◽  
Pei-Yu Wu ◽  
Wei-Min Yong ◽  
Jinn-Kong Sheu ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Ex Situ ◽  
Initial Growth ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

Micron-sized patterned sapphire substrates (PSS) are used to improve the performance of GaN-based light-emitting diodes (LEDs). However, the growth of GaN is initiated not only from the bottom c-plane but also from the sidewall of the micron-sized patterns. Therefore, the coalescence of these GaN crystals creates irregular voids. In this study, two kinds of nucleation layers (NL)—ex-situ AlN NL and in-situ GaN NL—were used, and the growth of sidewall GaN was successfully suppressed in both systems by modifying the micron-sized PSS surface.

Study on the morphology and shape control of volcano-shaped patterned sapphire substrates fabricated by imprinting and wet etching

CrystEngComm ◽  
2015 ◽  
Vol 17 (16) ◽  
pp. 3070-3075 ◽  
Author(s):  
S. X. Jiang ◽  
Z. Z. Chen ◽  
X. Z. Jiang ◽  
X. X. Fu ◽  
S. Jiang ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Shape Control ◽  
Wet Etching ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Novel Method ◽  
Patterned Sapphire Substrates

A novel method based on imprinting lithography and wet etching to fabricate a volcano-shaped patterned sapphire substrate (VPSS) is presented.

Crystallographic and topographical evolutions of a cylinder patterned sapphire substrate etched with a sulfuric acid and phosphoric acid mixture: an SEM and AFM study

CrystEngComm ◽  
2017 ◽  
Vol 19 (42) ◽  
pp. 6383-6390 ◽  
Author(s):  
Jian Shen ◽  
Dan Zhang ◽  
You Wang ◽  
Yang Gan
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Sapphire Substrate ◽  
Model System ◽  
Acid Mixture ◽  
Full Spectrum ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

Using cylinders as a model system, the full spectrum of crystallographic and topographical evolutions of patterned sapphire substrates is exhibited.

scholarly journals Novel patterned sapphire substrates for enhancing the efficiency of GaN-based light-emitting diodes

RSC Advances ◽  
2020 ◽  
Vol 10 (28) ◽  
pp. 16284-16290 ◽  
Author(s):  
Szu-Han Chao ◽  
Li-Hsien Yeh ◽  
Rudder T. Wu ◽  
Kyoko Kawagishi ◽  
Shih-Chieh Hsu
Keyword(s):  
Silicon Nitride ◽  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Air Voids ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

A novel patterned sapphire substrate composed of a silicon nitride barrier and air voids was developed for enhancing the efficiency of GaN-based light-emitting diodes.

Crystallographic plane and topography-dependent growth of semipolar InGaN nanorods on patterned sapphire substrates by molecular beam epitaxy

Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21951-21959 ◽  
Author(s):  
Jian Shen ◽  
Yulin Zheng ◽  
Zhenzhu Xu ◽  
Yuefeng Yu ◽  
Fangliang Gao ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Sapphire Substrate ◽  
Molecular Beam ◽  
High Index ◽  
Crystallographic Plane ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Dependent Growth ◽  
Crystallographic Planes ◽  
Patterned Sapphire Substrates

A patterned sapphire substrate with exposed high-index crystallographic planes, with well-organized step-terrace structures, facilitates the growth of well-aligned semipolar InGaN nanorods.

scholarly journals Effect of Top-Region Area of Flat-Top Pyramid Patterned Sapphire Substrate on the Optoelectronic Performance of GaN-Based Light-Emitting Diodes

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Hsu-Hung Hsueh ◽  
Sin-Liang Ou ◽  
Yu-Che Peng ◽  
Chiao-Yang Cheng ◽  
Dong-Sing Wuu ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

The flat-top pyramid patterned sapphire substrates (FTP-PSSs) have been prepared for the growth of GaN epilayers and the fabrication of lateral-type light-emitting diodes (LEDs) with an emission wavelength of approximately 470 nm. Three kinds of FTP-PSSs, which were denoted as FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C, respectively, were formed through the sequential wet etching processes. The diameters of circle areas on the top regions of these three FTP-PSSs were 1, 2, and 3 μm, respectively. Based on the X-ray diffraction results, the full-width at half-maximum values of rocking curves at (002) plane for the GaN epilayers grown on conventional sapphire substrate (CSS), FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 412, 238, 346, and 357 arcsec, while these values at (102) plane were 593, 327, 352, and 372 arcsec, respectively. The SpeCLED-Ratro simulation results reveal that the LED prepared on FTP-PSS-A has the highest light extraction efficiency than that of the other devices. At an injection current of 350 mA, the output powers of LEDs fabricated on CSS, FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 157, 254, 241, and 233 mW, respectively. The results indicate that both the crystal quality of GaN epilayer and the light extraction of LED can be improved via the use of FTP-PSS, especially for the FTP-PSS-A.

Fabrication of nano-patterned sapphire substrates by combining nanoimprint lithography with edge effects

CrystEngComm ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1794-1800 ◽  
Author(s):  
Yiyong Chen ◽  
Zhizhong Chen ◽  
Shengxiang Jiang ◽  
Chengcheng Li ◽  
Yifan Chen ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Edge Effects ◽  
Nanoimprint Lithography ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

A volcano-shaped nano-patterned sapphire substrate fabricated by combining nanoimprint lithography with edge effects.

Realization of low dislocation density AlN on a small-coalescence-area nano-patterned sapphire substrate

CrystEngComm ◽  
2019 ◽  
Vol 21 (15) ◽  
pp. 2490-2494 ◽  
Author(s):  
F. J. Xu ◽  
L. S. Zhang ◽  
N. Xie ◽  
M. X. Wang ◽  
Y. H. Sun ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Sapphire Substrate ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Truncated Cone ◽  
Low Dislocation Density ◽  
Patterned Sapphire Substrates

Growth behaviors of AlN on hexagonal configuration hole-type and truncated-cone-pillar-type nano-patterned sapphire substrates (NPSSs) have been investigated.

V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate

2018 ◽  
Vol 787 ◽  
pp. 37-41
Author(s):  
Huan You Wang ◽  
Qiao Lai Tan ◽  
Gui Jin
Keyword(s):  
Quantum Wells ◽  
Strain Relaxation ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Cross Sectional ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Multi Quantum Well ◽  
Patterned Sapphire Substrates

InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.

Gan-Based Leds Grown on Cone-Shaped Patterned Sapphire Substrates with Peripheral Air Voids by Lateral Etching

2011 ◽  
Vol 422 ◽  
pp. 542-546
Author(s):  
Nan Ming Lin ◽  
Shih Chang Shei ◽  
Shoou Jinn Chang ◽  
Wei Chih Lai ◽  
Yang Ya Yu ◽  
...  
Keyword(s):  
Output Power ◽  
Light Output ◽  
Patterned Sapphire Substrate ◽  
Air Voids ◽  
Sapphire Substrates ◽  
Flat Substrate ◽  
Laser Scribing ◽  
Mocvd Growth ◽  
One Step ◽  
Patterned Sapphire Substrates

In this study, the authors report that GaN-based LEDs prepared on 1.2μm, 1.4μm, and 1.7μm height of cone-shaped patterned sapphire substrates (CSPSS) with the formation of air voids at GaN/cone-shaped-patterned-sapphire-substrate interface by laser scribing and lateral etching with one-step MOCVD growth. With CSPSS, it can be seen that output powers were all significantly larger than that of LED with flat substrate (FS). Assisted by 20 min lateral etching, it was found that peripheral pyramid-like air-voids were formed on top of each cone of the CSPSS with 1.7μm height and the light output power increased by 13.8%, compared with the result of the CSPSS with 1.2μm height. Furthermore, it was also found that output power of LED prepared on 1.7μm height of CSPSS with 20 min lateral etching was 6.2 and 3.1% larger than those of LEDs prepared on 1.2μm and 1.4μm height of CSPSS with 20 min lateral etching, respectively.

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