scholarly journals Investigate the Double Peaks in Main Emission of UVB LEDs

2021 ◽  
Author(s):  
Tsung-Yen Liu ◽  
Shih-Ming Huang ◽  
Mu-Jen Lai ◽  
Rui-Sen Liu ◽  
Chieh-Hsiung Kuan ◽  
...  
Keyword(s):  
Layer Structure ◽  
Doping Profile ◽  
Energy Effect ◽  
Gaussian Peak ◽  
Charge Neutrality ◽  
Light Emitting ◽  
Exciton Emission ◽  
Double Peaks ◽  
Band Emission ◽  
Peak Emission

Abstract In this study we suppressed the parasitic emission caused by electron overflow found in typical UVB light-emitting diodes (LEDs). Furthermore, modulation of the p-layer structure and doping profile allowed us to decrease the relaxation time of the holes to reach conditions of quasi-charge neutrality in the UVB quantum well. Our UVB LED (sample A) exhibited a clear exciton emission, with its peak near 306 nm and a band-to-band emission at 303 nm. The relative intensity of the exciton emission of sample A decreased as a result of a thermal energy effect. At temperatures of up to 363 K, sample A displayed the exciton emission. Our corresponding UVC LED (sample B) exhibited only a Gaussian peak emission at a wavelength of approximately 272 nm.

scholarly journals Strain Compensation and Trade-Off Design Result in Exciton Emission at 306 nm from AlGaN LEDs at Temperatures up to 368 K

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6699
Author(s):  
Shih-Ming Huang ◽  
Mu-Jen Lai ◽  
Rui-Sen Liu ◽  
Tsung-Yen Liu ◽  
Ray-Ming Lin
Keyword(s):  
Quantum Wells ◽  
Layer Structure ◽  
Ultraviolet B ◽  
Energy Effect ◽  
Gaussian Peak ◽  
Trade Off ◽  
Light Emitting ◽  
Exciton Emission ◽  
Band Emission ◽  
Strain Compensation

In this study, we suppressed the parasitic emission caused by electron overflow found in typical ultraviolet B (UVB) and ultraviolet C (UVC) light-emitting diodes (LEDs). The modulation of the p-layer structure and aluminum composition as well as a trade-off in the structure to ensure strain compensation allowed us to increase the p-AlGaN doping efficiency and hole numbers in the p-neutral region. This approach led to greater matching of the electron and hole numbers in the UVB and UVC emission quantum wells. Our UVB LED (sample A) exhibited clear exciton emission, with its peak near 306 nm, and a band-to-band emission at 303 nm. The relative intensity of the exciton emission of sample A decreased as a result of the thermal energy effect of the temperature increase. Nevertheless, sample A displayed its exciton emission at temperatures of up to 368 K. In contrast, our corresponding UVC LED (sample B) only exhibited a Gaussian peak emission at a wavelength of approximately 272 nm.

Controlling the Mg doping profile in MOVPE-grown GaN/Al0.2Ga0.8N light-emitting diodes

2011 ◽  
Vol 8 (7-8) ◽  
pp. 2072-2074 ◽  
Author(s):  
Richard Gutt ◽  
Klaus Köhler ◽  
Joachim Wiegert ◽  
Lutz Kirste ◽  
Thorsten Passow ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Doping Profile ◽  
Light Emitting ◽  
Mg Doping

Influence of Mg doping profile on the electroluminescence properties of GaInN multiple-quantum-well light-emitting diodes

2004 ◽  
Author(s):  
Thilo Stephan ◽  
Klaus Koehler ◽  
Manfred Maier ◽  
Michael Kunzer ◽  
Peter Schlotter ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Doping Profile ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Mg Doping

Top-emission ultraviolet light-emitting diodes with peak emission at 280 nm

2002 ◽  
Vol 81 (5) ◽  
pp. 801-802 ◽  
Author(s):  
A. Yasan ◽  
R. McClintock ◽  
K. Mayes ◽  
S. R. Darvish ◽  
P. Kung ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Ultraviolet Light Emitting Diodes ◽  
Peak Emission

Color Tuning of Biomass-Derived Carbon Nanodots by Reaction Temperature Toward White Light-Emitting Diodes

NANO ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. 2050159
Author(s):  
Yi Gong ◽  
Yanbing Han ◽  
Fang Zhang ◽  
Mingyue Zhai ◽  
Xing Chen ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
White Light ◽  
Heating Temperature ◽  
Light Emitting Diode ◽  
Peak Position ◽  
Carbon Nanodots ◽  
One Pot ◽  
Light Emitting ◽  
White Leds ◽  
Band Emission

In this work, carbon nanodots (CNDs) were synthesized from extract of mango leaves. Sphere nanodots were formed rapidly by one-step microwave heating. The photoluminescence (PL) of the CNDs was found greatly dependent on the reaction temperature. The emission peak position of the CNDs changed from 550[Formula: see text]nm to 430[Formula: see text]nm when the heating temperature increased from 120[Formula: see text]C to 150[Formula: see text]C. Particularly, the CNDs synthesized at 130[Formula: see text]C showed multi-band emission at 411[Formula: see text]nm, 480[Formula: see text]nm and 530[Formula: see text]nm, providing emitting color from blue to yellow. Moreover, the free chlorophyll molecules in the solution added red fluorescence at 670[Formula: see text]nm, and the integrated emitting color of the CNDs solution was close to white. Coated on a commercial 365[Formula: see text]nm light-emitting diode (LED) chip, the CNDs showed greenish white light with CIE coordinates of (0.37, 0.44). This work provided a one-pot, rapid and green method to obtain multi-emissive CNDs toward white LEDs.

Control of Narrow-Band Emission in Phosphor Materials for Application in Light-Emitting Diodes

2018 ◽  
Vol 3 (10) ◽  
pp. 2573-2586 ◽  
Author(s):  
Mu-Huai Fang ◽  
Julius L. Leaño ◽  
Ru-Shi Liu
Keyword(s):  
Light Emitting Diodes ◽  
Narrow Band ◽  
Light Emitting ◽  
Band Emission

scholarly journals Double-layer structure in polar mesospheric clouds observed from SOFIE/AIM

2017 ◽  
Vol 35 (2) ◽  
pp. 295-309 ◽  
Author(s):  
Haiyang Gao ◽  
Gordon G. Shepherd ◽  
Yuanhe Tang ◽  
Lingbing Bu ◽  
Zhen Wang
Keyword(s):  
Double Layer ◽  
Lower Layer ◽  
Layer Structure ◽  
Polar Mesospheric Clouds ◽  
Double Peaks ◽  
Double Layer Structure ◽  
Ice Water Content ◽  
Background Temperature ◽  
Mesospheric Clouds ◽  
Ice Water

Abstract. Double-layer structures in polar mesospheric clouds (PMCs) are observed by using Solar Occultation for Ice Experiment (SOFIE) data between 2007 and 2014. We find 816 and 301 events of double-layer structure with percentages of 10.32 and 7.25 % compared to total PMC events, and the mean distances between two peaks are 3.06 and 2.73 km for the Northern Hemisphere (NH) and Southern Hemisphere (SH) respectively. Double-layer PMCs almost always have less mean ice water content (IWC) than daily IWC during the core of the season, but they are close to each other at the beginning and the end. The result by averaging over all events shows that the particle concentration has obvious double peaks, while the particle radius exhibits an unexpected monotonic increase with decreasing altitude. By further analysis of the background temperature and water vapour residual profiles, we conclude that the lower layer is a reproduced one formed at the bottom of the upper layer. 56.00 and 47.51 % of all double-layer events for the NH and SH respectively have temperature enhancements larger than 2 K locating between their double peaks. The longitudinal anti-correlation between the gravity waves' (GWs') potential energies and occurrence frequencies of double-layer PMCs suggests that the double-layer PMCs tend to form in an environment where the GWs have weaker intensities.

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