280 nm Emission Deep UV LEDs with Integrated Fresnel Microlenses

2006 ◽  
Vol 916 ◽  
Author(s):  
Mikhail E Gaevski ◽  
Maxim Shatalov ◽  
Shuai Wu ◽  
Asif M Khan
Keyword(s):  
Focal Plane ◽  
Background Radiation ◽  
Optical Systems ◽  
Outer Diameter ◽  
Back Side ◽  
Focal Distance ◽  
Light Emitting ◽  
Before And After ◽  
Deep Uv ◽  
Uv Leds

AbstractWe report on the integration of flowable oxide based Fresnel microlenses with AlGaN based 280 nm light emitting diodes (LED). The lenses were fabricated on the back side of the LED sapphire substrates using direct electron beam writing. Ten concentric rings with different width and variable thickness were designed for 360 degree phase correction. Within each ring the thickness was varied in five steps to approximate a linear profile. The width of each thickness step varied from 100 nm to several microns. Outer diameter of the lens was 65μm. A focal distance of 68 μm was measured for the fabricated microlenses. At the focal plane a FWHM of intensity profile as small as 14 μm was measured for lenses integrated with 30 μm diameter UV LEDs . The maximum intensity at focal plane exceeded the background radiation by a factor of 50. Comparison of the LED performance before and after the lens fabrication did not reveal any degradation of integral efficiency of devices. These results demonstrate the feasibility of using flowable oxide Fresnel microlenses in optical systems based on micro-pixel deep UV AlGaN LEDs.

Deep Ultraviolet Light Emitting Diodes with Emission below 300 nm

2005 ◽  
Vol 892 ◽  
Author(s):  
M. Asif Khan
Keyword(s):  
Multiple Quantum Well ◽  
Structure Design ◽  
Multiple Quantum ◽  
Device Structure ◽  
Light Emitting ◽  
Uv Led ◽  
Excellent Research ◽  
Deep Uv ◽  
P Type ◽  
Uv Leds

AbstractIn this paper we will describe the problems in growth and fabrication of deep UV LED devices and the approaches that we have used to grow AlGaN-based multiple quantum well deep UV LED structures and to overcome issues of doping efficiency, cracking, and slow growth rates both for the n- and the p-type layers of the device structures. Several innovations in structure growth, device structure design and fabrication and packaging have led to the fabrication of devices with emission from 250-300 nm and cw-milliwatt powers at pump currents of only 20 mA (Vf ≤ 6 V). Record wall plug efficiencies above 1.5 % are now achievable for devices with emission at 280 nm. Thermal management and a proper device design are not only key factors in achieving these record performance numbers but are also crucial to device reliability. We will also discuss some of our initial research to clarify the factors influencing the lifetime of the deep UV LEDs. In addition to our own work, we will review the results from the excellent research carried out at several other laboratories worldwide.

Rare-earth doped gadolinia based phosphors for potential multicolor and white light emitting deep UV LEDs

2009 ◽  
Vol 20 (12) ◽  
pp. 125707 ◽  
Author(s):  
Vinila Bedekar ◽  
Dimple P Dutta ◽  
M Mohapatra ◽  
S V Godbole ◽  
R Ghildiyal ◽  
...  
Keyword(s):  
Rare Earth ◽  
White Light ◽  
Light Emitting ◽  
Deep Uv ◽  
Uv Leds ◽  
Rare Earth Doped

Eu2+/Eu3+-emission-ratio-tunable CaZr(PO4)2:Eu phosphors synthesized in air atmosphere for potential white light-emitting deep UV LEDs

2014 ◽  
Vol 2 (2) ◽  
pp. 312-318 ◽  
Author(s):  
Jun-Cheng Zhang ◽  
Yun-Ze Long ◽  
Hong-Di Zhang ◽  
Bin Sun ◽  
Wen-Peng Han ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting ◽  
Emission Ratio ◽  
Air Atmosphere ◽  
Deep Uv ◽  
Uv Leds

Performance of vertical type deep UV light-emitting diodes depending on the Ga-face n-contact hole density

2021 ◽  
Vol 118 (23) ◽  
pp. 231102
Author(s):  
Youn Joon Sung ◽  
Dong-Woo Kim ◽  
Geun Young Yeom ◽  
Kyu Sang Kim
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Hole Density ◽  
Light Emitting ◽  
Deep Uv

scholarly journals 310 nm UV-LEDs attenuate imiquimod-induced psoriasis-like skin lesions in C57BL/6 mice and inhibit IL-22-induced STAT3 expression in HaCaT cells

2020 ◽  
Vol 19 (8) ◽  
pp. 1009-1021
Author(s):  
Tae-Rin Kwon ◽  
Sung-Eun Lee ◽  
Jong Hwan Kim ◽  
You Na Jang ◽  
Su-Young Kim ◽  
...  
Keyword(s):  
Light Source ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Skin Lesions ◽  
Hacat Cells ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy.

Robust 285 nm Deep UV Light Emitting Diodes over Metal Organic Hydride Vapor Phase Epitaxially Grown AlN/Sapphire Templates

2007 ◽  
Vol 46 (No. 23) ◽  
pp. L537-L539 ◽  
Author(s):  
Vinod Adivarahan ◽  
Qhalid Fareed ◽  
Surendra Srivastava ◽  
Thomas Katona ◽  
Mikhail Gaevski ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Light Emitting ◽  
Organic Hydride ◽  
Metal Organic ◽  
Deep Uv

A Detailed Study of a Novel Wafer Separation Method for Surface Sensitive MEMS Wafers

2012 ◽  
Vol 1415 ◽  
Author(s):  
K. Malachowski ◽  
S. Severi ◽  
R. Van Hoof ◽  
S. Sangameswaran ◽  
S. Genda ◽  
...  
Keyword(s):  
Process Integration ◽  
Separation Method ◽  
Work Design ◽  
Back Side ◽  
Design Rules ◽  
Micro Electro Mechanical Systems ◽  
Particle Contamination ◽  
Before And After ◽  
Common Technique ◽  
Process Speed

ABSTRACTAbrasive blade dicing is the most common technique for die separation. In this work an alternative dry and non-abrasive die separation method, which is known as "Stealth dicing", is assessed for surface-sensitive MEMS (Micro Electro Mechanical Systems) wafers. The dicing performance and capability of the system is investigated on 200mm full thickness wafers with and without MEMS structures. The diced wafers are analyzed with respect to the silicon cutting quality, possible particle contamination, the condition of functional structures and their mechanical and electrical functionality. In addition the performance and limitations of two different Stealth Dicing Engine (SDE) types, SDE01 and SDE03, are compared to each other with respect to their performance on MEMS wafer dicing.From this work design rules and proper dimensions of the scribe line can be determined. Process integration solutions, describing steps before and after the Stealth dicing process, including the contact-less dicing tape application to the wafer back side and the final die separation method by tape stretching, are presented. It was also found that the SDE03 laser with its outstanding performance in terms of process speed and separation quality can bring a breakthrough for applying this technology for MEMS wafers.

Reactivity of bilirubin photoisomers on the measurement of direct bilirubin using vanadic acid method

2017 ◽  
Vol 55 (2) ◽  
pp. 296-298
Author(s):  
Hitoshi Okada ◽  
Susumu Itoh ◽  
Shohei Kawamoto ◽  
Miyo Ozaki ◽  
Takashi Kusaka
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Direct Bilirubin ◽  
Acid Oxidation ◽  
Albumin Solution ◽  
Light Emitting ◽  
Oxidation Method ◽  
Before And After ◽  
Vanadic Acid ◽  
Human Serum Albumin Solution

Objective Investigation of the reactivity of fractions of bilirubin photoisomers with the vanadic acid oxidation method. Methods Bilirubin photoisomers were prepared by irradiating a bilirubin/human serum albumin solution with blue light emitting diode. Direct bilirubin and bilirubin fractions were measured using the vanadic acid oxidation method and high-performance liquid chromatography in the sample before and after irradiation. Results Direct bilirubin was increased in the solution containing bilirubin photoisomers. ( EE)-/( EZ) -cyclobilirubin-IXα and ( ZE)-/( EZ)-bilirubin-IXα completely disappeared after the addition of vanadic acid. Conclusion Bilirubin photoisomers reacted as direct bilirubin in the vanadic acid oxidation method.

Realization of high-efficiency deep-UV LEDs using transparent p-AlGaN contact layer

2013 ◽  
Vol 10 (11) ◽  
pp. 1521-1524 ◽  
Author(s):  
Noritoshi Maeda ◽  
Hideki Hirayama
Keyword(s):  
High Efficiency ◽  
Contact Layer ◽  
Deep Uv ◽  
Uv Leds
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