Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

2014 ◽  
Vol 105 (1) ◽  
pp. 013108 ◽  
Author(s):  
Yonghui Zhang ◽  
Tongbo Wei ◽  
Zhuo Xiong ◽  
Liang Shang ◽  
Yingdong Tian ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Multiple Exposure ◽  
Light Emitting

&[mu]-Watt Enhanced Electroluminescent Power of Silicon Nanocrystal Light-Emitting Diodes Made on Nano-Scale Silicon-Tip-Array Substrate

2007 ◽  
Vol 989 ◽  
Author(s):  
Gong-Ru Lin ◽  
Chun-Jung Lin
Keyword(s):  
Light Emitting Diode ◽  
Optical Power ◽  
Oxide Semiconductor ◽  
Si Substrate ◽  
Light Emitting ◽  
Pillar Array ◽  
Turn On ◽  
Air Interface ◽  
Order Of Magnitude ◽  
Etching Mask

AbstractA Si nanocrystal based metal-oxide-semiconductor light-emitting diode (MOSLED) on Si nano-pillar array is preliminarily demonstrated. Rapid self-aggregation of Ni nanodots on Si substrate covered with a thin SiO2 buffered layer is employed as the etching mask for obtaining Si nano-pillar array. Dense Ni nanodots with size and density of 30 nm and 2.8×10 cm-2, respectively, can be formatted after rapid thermal annealing at 850°C for 22 s. The nano-roughened Si surface contributes to both the relaxation of total-internal reflection at device-air interface and the Fowler-Nordheim tunneling enhanced turn-on characteristics, providing the MOSLED a maximum optical power of 0.7 uW obtained at biased current of 375 uA. The optical intensity, turn-on current, power slope and external quantum efficiency of the MOSLED are 140 μW/cm2, 5 uA, 2+-0.8 mW/A and 1×10-3, respectively, which is almost one order of magnitude larger than that of a same device made on smooth Si substrate.

Reduction of Thermal Resistance and Optical Power Loss Using Thin-Film Light-Emitting Diode (LED) Structure

2015 ◽  
Vol 62 (11) ◽  
pp. 6925-6933 ◽  
Author(s):  
Huan Ting Chen ◽  
Yuk Fai Cheung ◽  
Hoi Wai Choi ◽  
Siew Chong Tan ◽  
S. Y. Hui
Keyword(s):  
Thin Film ◽  
Thermal Resistance ◽  
Power Loss ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Light Emitting

N-face GaN substrate roughening for improved performance GaN-on-GaN LED

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ezzah Azimah Alias ◽  
Muhammad Esmed Alif Samsudin ◽  
Steven DenBaars ◽  
James Speck ◽  
Shuji Nakamura ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Ammonium Hydroxide ◽  
Content Type ◽  
Light Emitting ◽  
Gan Led ◽  
Improved Performance ◽  
Substrate Roughening

Purpose This study aims to focus on roughening N-face (backside) GaN substrate prior to GaN-on-GaN light-emitting diode (LED) growth as an attempt to improve the LED performance. Design/methodology/approach The N-face of GaN substrate was roughened by three different etchants; ammonium hydroxide (NH4OH), a mixture of NH4OH and H2O2 (NH4OH: H2O2) and potassium hydroxide (KOH). Hexagonal pyramids were successfully formed on the surface when the substrate was subjected to the etching in all cases. Findings Under 30 min of etching, the highest density of pyramids was obtained by NH4OH: H2O2 etching, which was 5 × 109 cm–2. The density by KOH and NH4OH etchings was 3.6 × 109 and 5 × 108 cm–2, respectively. At standard operation of current density at 20 A/cm2, the optical power and external quantum efficiency of the LED on the roughened GaN substrate by NH4OH: H2O2 were 12.3 mW and 22%, respectively, which are higher than its counterparts. Originality/value This study demonstrated NH4OH: H2O2 is a new etchant for roughening the N-face GaN substrate. The results showed that such etchant increased the density of the pyramids on the N-face GaN substrate, which subsequently resulted in higher optical power and external quantum efficiency to the LED as compared to KOH and NH4OH.

Organic Light-Emitting Diode Microcavities from Transparent Conducting Metal Oxide Photonic Crystals

Nano Letters ◽  
2011 ◽  
Vol 11 (4) ◽  
pp. 1457-1462 ◽  
Author(s):  
Daniel P. Puzzo ◽  
Michael G. Helander ◽  
Paul G. O’Brien ◽  
Zhibin Wang ◽  
Navid Soheilnia ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Metal Oxide ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Transparent Conducting

Enhanced Optical Power of InGaN/GaN Light-Emitting Diode by AlGaN Interlayer and Electron Blocking Layer

2012 ◽  
Vol 24 (22) ◽  
pp. 1991-1994 ◽  
Author(s):  
Sang-Jun Lee ◽  
Chu-Young Cho ◽  
Sang-Hyun Hong ◽  
Sang-Heon Han ◽  
Sukho Yoon ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Optical Power ◽  
Blocking Layer ◽  
Electron Blocking Layer ◽  
Light Emitting

The Color Mixing White-Light LEDs

2013 ◽  
Vol 378 ◽  
pp. 440-443
Author(s):  
Chiu Jung Yang ◽  
Chien Sheng Huang ◽  
Chih Wei Chen ◽  
Po Wen Chen
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Integrating Sphere ◽  
Light Spectrum ◽  
Light Emitting ◽  
Driver Circuit ◽  
Color Mixing ◽  
Color Rendering

Thepaperis discussedin coloruniformity study.The experiment divided into two steps in this study,first is modules design and simulation. Second is fabrication and measurement.After measure the LEDs property, calculating the ratio of each colored LEDs by using Grassmanns Law,modeling by Solidworks, and simulating the front study by optical software TracePro.Using four-color mixing with self-developed formula to avoid the present white light emitting diode patent, and the four-color grains are Red, Green, Blue and adding Y to modify the overall quality of the mixed light.The phosphorproduceSteabler-Wronsk hardly in the high temperatureas compared tofour-color mixing.Using four-color mixing to producehigher color rendering index than yellow phosphor.Series-parallel array of grain arrangement adopted to achieve the high demand for uniformity, while simplifying the design conditions by a certain current instead of the general mixed light-driven complex driver circuit,the completion of the mixing module using integrating sphere, light spectrum on the spectrophotometer, optical power, color coordinates values, such as mixing uniformity measurements.The chromaticity coordinates errors after complete results of the mixing module measurement and simulation can be controlled under (0.01x, 0.01y).

Metalloporphyrins into Mesoporous Photonic Crystals: Towards Nanostructured Sensing Devices

2019 ◽  
Author(s):  
Rolando M. Caraballo ◽  
Diego Onna ◽  
Nicolás López Abdala ◽  
Galo J.A.A. Soler-Illia ◽  
Mariana Hamer
Keyword(s):  
Photonic Crystals ◽  
Hybrid Material ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Optical Filters ◽  
Spectral Window ◽  
Light Emitting ◽  
Future Design ◽  
Mesoporous Oxide ◽  
Specific Reactivity

<p>Metalloporphyrins are molecules capable of optically sensing targets due to their specific reactivity. Shifts in metalloporphyrins spectra are usually in the order of 30 nm, requiring a spectrophotometer for transducing the analyte concentration. Mesoporous oxide thin films photonic crystals (PC) act as optical filters, while their pores can host molecular moieties. In this work used a metalloporphyrin, Mn<sup>III</sup> meso-tetra(N-methyl-4-pyridyl) porphyrin (MP), to add a recognition functionality to a PC and, at the same time, retain their pore network, in order to develop a versatile and portable sensing device for volatile amines. The hybrid material MP@PC was prepared by immersion of the PC, synthesized from two mesoporous oxides with different refractive index, in an MP solution. The system was characterized by UV-Vis absorption and FTIR spectroscopies, and SEM microscopy. Sensing of small molecules was tested using ethylenediamine (EDA) as a volatile amine model, showing an absorbance increase in the PC spectral window with promising analytical parameters. The hybrid material presents enhanced sensing capabilities compared to MP or PC alone. A prototype device was built, aiming for a future design of simple, low-cost equipment, with a light emitting diode and a light-dependent resistor, including the MP@PC sensor. The device is capable of sensing with only 1.52 μg of MP on a 1 cm<sup>2</sup> glass slide and it is easily prepared and showed a very small detection limit.</p>

Interactions of Diffraction Modes Contributed From Surface Photonic Crystals and Nanoholes in a GaN-Based Light-Emitting Diode

2011 ◽  
Vol 29 (24) ◽  
pp. 3772-3776 ◽  
Author(s):  
Szu-Chieh Wang ◽  
Yun-Wei Cheng ◽  
Yu-Feng Yin ◽  
Liang-Yi Chen ◽  
Liang-Yu Su ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Light Emitting Diode ◽  
Light Emitting
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