scholarly journals Mean Differential Continuous Pulse Method for Accurate Optical Measurements of Light-Emitting Diodes and Laser Diodes

2021 ◽  
Vol 126 ◽  
Author(s):  
Yuqin Zong ◽  
Jeff Hulett ◽  
Naomasa Koide ◽  
Yoshiki Yamaji ◽  
C. Cameron Miller
Keyword(s):  
Light Emitting Diodes ◽  
Laser Diodes ◽  
Pulse Method ◽  
Optical Measurements ◽  
Error Sources ◽  
Light Emitting ◽  
Order Of Magnitude ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Continuous Pulse

Limited sources exist for the application of germicidal ultraviolet (GUV) radiation. Ultraviolet light-emitting diodes (UV-LEDs) have significantly improved in efficiency and are becoming another viable source for GUV. We have developed a mean differential continuous pulse method (M-DCP method) for optical measurements of light-emitting diodes (LEDs) and laser diodes (LDs). The new M-DCP method provides an improvement on measurement uncertainty by one order of magnitude compared to the unpublished differential continuous pulse method (DCP method). The DCP method was already a significant improvement of the continuous pulse method (CP method) commonly used in the LED industry. The new M-DCP method also makes it possible to measure UV-LEDs with high accuracy. Here, we present the DCP method, discuss the potential systematic error sources in it, and present the M-DCP method along with its reduced systematic errors. This paper also presents the results of validation measurement of LEDs using the M-DCP method and common test instruments.

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.

Development of an Al2O3 filled composite for the bracket of ultraviolet light-emitting diodes (UV-LEDs)

2018 ◽  
Vol 83 ◽  
pp. 356-362 ◽  
Author(s):  
Lei Zhang ◽  
Yiting Zheng ◽  
Jiale Mao ◽  
Shuang Wang ◽  
Ruotian Fu ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Filled Composite

ACCURATE MEASUREMENT OF ULTRAVIOLET LIGHT-EMITTING DIODES

2021 ◽  
Author(s):  
C. Yuqin Zong ◽  
Cameron Miller
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Light Emitting ◽  
Type D ◽  
Uv Led ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

We have developed a new calibration capability for 200 nm to 400 nm ultraviolet light-emitting diodes (UV LEDs) using a Type D gonio-spectroradiometer. The recently-introduced mean differential continuous pulse (M-DCP) method is used to overcome the measurement difficulty associated with the initial forward voltage, VF, anomaly of a UV LED, which makes it impossible to use VF to infer junction temperature, TJ, during pulsed operation. The new measurement facility was validated indirectly by comparing the measured total luminous flux of a white LED with that measured using the NIST’s 2.5 m absolute integrating sphere. The expanded calibration uncertainty for the total radiant flux is approximately 2 % to 3 % (k = 2) depending the wavelength of the UV LED.

Characterization of Minority-Carrier Hole Transport in Nitride-Based Light-Emitting Diodes with Optical and Electrical Time-Resolved Techniques

2004 ◽  
Vol 831 ◽  
Author(s):  
R. J. Kaplar ◽  
S. R. Kurtz ◽  
D. D. Koleske ◽  
A. A. Allerman ◽  
A. J. Fischer ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Minority Carrier ◽  
Hole Transport ◽  
Optical Measurements ◽  
Hole Density ◽  
Transport Parameters ◽  
Two Phase ◽  
Time Resolved ◽  
Light Emitting ◽  
Order Of Magnitude

ABSTRACTForward-to-reverse bias step-recovery measurements were performed on In.07Ga.93N/GaN and Al.36Ga.64N/Al.46Ga.54N quantum-well (QW) light-emitting diodes grown on sapphire. With the QW sampling the minority-carrier hole density at a single position, distinctive two-phase optical decay curves were observed. Using diffusion equation solutions to self-consistently model both the electrical and optical responses, hole transport parameters τp = 758 ± 44 ns, Lp = 588 ± 45 nm, and μp = 0.18 ± 0.02 cm2/Vs were obtained for GaN. The mobility was thermally activated with an activation energy of 52 meV, suggesting trap-modulated transport. Optical measurements of sub-bandgap peaks exhibited slow responses approaching the bulk lifetime. For Al.46Ga.54N, a longer lifetime of τp = 3.0 μs was observed, and the diffusion length was shorter, Lp ≈ 280 nm. Mobility was an order of magnitude smaller than in GaN, μp ≈ 10−2 cm2/Vs, and was insensitive to temperature, suggesting hole transport through a network of defects.

Room and Cryogenic Temperature Operation of 280 nm Deep Ultraviolet Light Emitting Diodes

2002 ◽  
Vol 743 ◽  
Author(s):  
Maxim Shatalov ◽  
Vinod Adivarahan ◽  
Jian Ping Zhang ◽  
Ashay Chitnis ◽  
Shuai Wu ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Radiative Recombination ◽  
Light Emitting Diodes ◽  
Deep Level ◽  
Optical Power ◽  
Light Emitting ◽  
Spectral Performance ◽  
Order Of Magnitude ◽  
Deep Ultraviolet ◽  
Ultraviolet Light Emitting Diodes

ABSTRACTWe present a study of the electrical and optical characteristics of 280 nm emission deep ultraviolet light emitting diodes (LED) at room and cryogenic temperatures. At low bias the defect assisted carrier tunneling primarily determines the current conduction. The room-temperature spectral performance and optical power are limited mostly by pronounced deep level defect assisted radiative and non-radiative recombination as well as poor electron confinement in the active region. At temperatures below 100 K the electroluminescence peak intensity increases by more than one order of magnitude due to suppression of non-radiative recombination channels indicating that with a proper device design and improved material quality, milliwatt power 280 nm LED are viable.

scholarly journals Comparison of ultraviolet light emitting diodes with traditional UV for greywater disinfection

2014 ◽  
Vol 5 (1) ◽  
pp. 17-27 ◽  
Author(s):  
M. J. Crook ◽  
B. Jefferson ◽  
O. Autin ◽  
J. MacAdam ◽  
A. Nocker
Keyword(s):  
Particle Size ◽  
Ultraviolet Light ◽  
Water Reuse ◽  
Light Emitting Diodes ◽  
Microbial Inactivation ◽  
Small Scale ◽  
Light Emitting ◽  
Uv Leds ◽  
The Impact ◽  
Ultraviolet Light Emitting Diodes

The current technological status of ultraviolet light emitting diodes (UV-LEDs) has reached a point where small-scale ultraviolet (UV) water disinfection applications, that is, for greywater reuse appear increasingly promising. This study compares the germicidal and economical aspects of UV-LEDs with traditional UV. Pure cultures and environmental greywater samples were exposed to different radiation doses from both UV sources with the germicidal effect comparative at equivalent doses. The impact of particle size on disinfection efficiency was investigated in two greywater fractions of varying mean particle size. Disinfection efficiency was found to be dependent on particle size with larger particles reducing microbial inactivation for both UV sources. Post-UV blending to detach particle-associated coliforms resulted in higher bacterial counts for both UV sources although to a lesser extent for UV-LEDs suggesting that it might be less affected by the presence of particles than traditional UV sources, possibly due to the UV radiation being emitted by multiple diodes at different angles compared to the traditional UV collimated beam setup. Nevertheless, removal of particles prior to UV disinfection is necessary to meet strict water reuse standards. Although UV-LEDs are currently prohibitively expensive, improvements in performance indicators might make this technology economically competitive within the next few years.

Ultraviolet light emitting diodes using non-polar A-plane AlGaN multiple quantum wells

2006 ◽  
Vol 955 ◽  
Author(s):  
Ramya Chandrasekaran ◽  
Anirban Bhattacharyya ◽  
Ryan France ◽  
Christos Thomidis ◽  
Adrian Williams ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Voltage ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Electro Luminescence

ABSTRACTIn this paper, we report the growth and fabrication of non-polar A-plane AlGaN multiple quantum well based ultraviolet light emitting diodes (UV-LEDs). The LEDs were grown on R-plane sapphire substrates using molecular beam epitaxy (MBE). The Current-voltage characteristics of the fabricated devices demonstrated rectifying behavior with a series resistance of 38 ohms. An electro-luminescence emission at 338 nm was obtained.

InAlGaN optical emitters: laser diodes with non-epitaxial cladding layers and ultraviolet light-emitting diodes

2011 ◽  
Author(s):  
Christopher Chua ◽  
Zhihong Yang ◽  
Clifford Knollenberg ◽  
Mark Teepe ◽  
Bowen Cheng ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Laser Diodes ◽  
Light Emitting ◽  
Ultraviolet Light Emitting Diodes ◽  
Cladding Layers
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