scholarly journals AlGaN Nanowires for Ultraviolet Light-Emitting: Recent Progress, Challenges, and Prospects

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 125 ◽  
Author(s):  
Songrui Zhao ◽  
Jiaying Lu ◽  
Xu Hai ◽  
Xue Yin
Keyword(s):  
Aluminum Gallium Nitride ◽  
Recent Progress ◽  
Stark Effect ◽  
Uv Light ◽  
Chemical Vapor ◽  
Light Emitting ◽  
Quantum Confined Stark Effect ◽  
Recent Developments ◽  
Uv Leds ◽  
Made In

In this paper, we discuss the recent progress made in aluminum gallium nitride (AlGaN) nanowire ultraviolet (UV) light-emitting diodes (LEDs). The AlGaN nanowires used for such LED devices are mainly grown by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD); and various foreign substrates/templates have been investigated. Devices on Si so far exhibit the best performance, whereas devices on metal and graphene have also been investigated to mitigate various limitations of Si substrate, e.g., the UV light absorption. Moreover, patterned growth techniques have also been developed to grow AlGaN nanowire UV LED structures, in order to address issues with the spontaneously formed nanowires. Furthermore, to reduce the quantum confined Stark effect (QCSE), nonpolar AlGaN nanowire UV LEDs exploiting the nonpolar nanowire sidewalls have been demonstrated. With these recent developments, the prospects, together with the general challenges of AlGaN nanowire UV LEDs, are discussed in the end.

OPTICAL PROPERTIES OF GaInN/GaN MULTI-QUANTUM WELL STRUCTURE AND LIGHT EMITTING DIODE GROWN BY METALORGANIC CHEMICAL VAPOR PHASE EPITAXY

2007 ◽  
Vol 17 (01) ◽  
pp. 81-84
Author(s):  
J. Senawiratne ◽  
M. Zhu ◽  
W. Zhao ◽  
Y. Xia ◽  
Y. Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Well ◽  
Stark Effect ◽  
Light Emitting Diode ◽  
Chemical Vapor ◽  
Green Emission ◽  
Luminescence Spectroscopy ◽  
Light Emitting ◽  
Quantum Confined Stark Effect ◽  
Multi Quantum Well

Optical properties of green emission Ga 0.80 In 0.20 N/GaN multi-quantum well and light emitting diode have been investigated by using photoluminescence, cathodoluminescence, electroluminescence, and photoconductivity. The temperature dependent photoluminescence and cathodoluminescence studies show three emission bands including GaInN/GaN quantum well emission centered at 2.38 eV (~ 520 nm). The activation energy of the non-radiative recombination centers was found to be ~ 60 meV. The comparison of photoconductivity with luminescence spectroscopy revealed that optical properties of quantum well layers are strongly affected by the quantum-confined Stark effect.

Luminescence Properties of InGaN/GaN Green Light-Emitting Diodes with Si-Doped Graded Short-Period Superlattice

2021 ◽  
Vol 21 (11) ◽  
pp. 5648-5652
Author(s):  
ll-Wook Cho ◽  
Bom Lee ◽  
Kwanjae Lee ◽  
Jin Soo Kim ◽  
Mee-Yi Ryu
Keyword(s):  
Optical Properties ◽  
Decay Time ◽  
Stark Effect ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Time Resolved ◽  
Light Emitting ◽  
Quantum Confined Stark Effect ◽  
Short Period ◽  
Si Doped

The optical properties of InGaN/GaN green light-emitting diodes (LEDs) with an undoped graded short-period superlattice (GSL) and a Si-doped GSL (SiGSL) were investigated using photoluminescence (PL) and time-resolved PL spectroscopies. For comparison, an InGaN/GaN conventional LED (CLED) without the GSL structure was also grown. The SiGSL sample showed the strongest PL intensity and the largest PL peak energy because of band-filling effect and weakened quantum- confined stark effect (QCSE). PL decay time of SiGSL sample at 10 K was shorter than those of the CLED and GSL samples. This finding was attributed to the oscillator strength enhancement by the reduced QCSE due to the Coulomb screening by Si donors. In addition, the SiGSL sample exhibited the longest decay time at 300 K, which was ascribed to the reduced defect and dislocation density. These results indicate that insertion of the Si-doped GSL structure is an effective strategy for improving the optical properties in InGaN/GaN green LEDs.

scholarly journals Transcriptome and metabolome analyses revealed that narrowband 280 and 310 nm UV-B induce distinctive responses in Arabidopsis

2021 ◽  
Author(s):  
Tomohiro Tsurumoto ◽  
Yasuo Fujikawa ◽  
Daisaku Ohta ◽  
Atsushi Okazawa
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Uv Light ◽  
Current Model ◽  
Phenylpropanoid Pathway ◽  
Metabolic Responses ◽  
Uv Resistance ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds ◽  
Led Irradiation

SUMMARYIn plants, the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) perceives UV-B and induces UV-B responses including synthesis of UV-B absorbing phenolic compounds such as anthocyanins. UVR8 absorbs a range of UV-B (260–335 nm). However, the responsiveness of plants to each UV-B wavelength has not been intensively studied so far. Here, we performed transcriptome and metabolome analyses of Arabidopsis using UV light emitting diodes (LEDs) with peak wavelengths of 280 and 310 nm to investigate the differences in the wavelength-specific UV-B responses. Irradiation with both UV-LEDs induced gene expression of the transcription factor ELONGATED HYPOCOTYL 5 (HY5), which has a central role in the UVR8 signaling pathway. However, the overall transcriptomic and metabolic responses to 280 and 310 nm UV-LED irradiation were different. Most of the known UV-B-responsive genes, such as salicylic acid, jasmonic acid, and defense-related genes, responded only to 280 nm UV-LED irradiation. Lipids, polyamines and organic acids were the metabolites most affected by 280 nm UV-LED irradiation, whereas the effect of 310 nm UV-LED irradiation on the metabolome was considerably less. Enzymatic genes involved in the phenylpropanoid pathway upstream in anthocyanin biosynthesis were up-regulated only by 280 nm UV-LED irradiation. On the other hand, no enzymatic genes downstream in anthocyanin biosynthesis were induced by the UV-LEDs, but rather, they were down-regulated by 310 nm UV-LED irradiation. These results revealed that the responsivenesses of Arabidopsis to 280 and 310 nm UV-B were significantly different, suggesting that UV-B signaling is mediated by more complex pathways than the current model.

Growth of deep-UV light-emitting diodes by metalorganic chemical vapor deposition

2004 ◽  
Author(s):  
Alireza Yasan ◽  
Ryan McClintock ◽  
Kathryn A. Mayes ◽  
Derek J. Shiell ◽  
Shaban R. Darvish ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Chemical Vapor ◽  
Light Emitting ◽  
Deep Uv ◽  
Metalorganic Chemical

Temperature dependence of energy transfer in tunable white light-emitting phosphor BaY2Si3O10:Bi3+,Eu3+ for near UV LEDs

2015 ◽  
Vol 3 (42) ◽  
pp. 11151-11162 ◽  
Author(s):  
Hongpeng Zhou ◽  
Qingping Wang ◽  
Ye Jin
Keyword(s):  
Energy Transfer ◽  
Temperature Dependence ◽  
White Light ◽  
Light Emission ◽  
Uv Light ◽  
Energy Transfer Efficiency ◽  
White Light Emission ◽  
Transfer Efficiency ◽  
Light Emitting ◽  
Uv Leds

The white light emission of BaY2Si3O10:0.01 Bi3+, mEu3+ phosphor can be realized and utilizing the energy transfer under near UV light pumped. The energy transfer efficiency between Bi(i) and Bi(ii) change with the temperature increasing due to phonon-assisted process. It is rare in the experiment on directly proof with the phonon-assisted energy transfer.

Nonpolar/Semipolar GaN Technology for Violet, Blue, and Green Laser Diodes

MRS Bulletin ◽  
2009 ◽  
Vol 34 (5) ◽  
pp. 324-327 ◽  
Author(s):  
Hiroaki Ohta ◽  
Kuniyoshi Okamoto
Keyword(s):  
Stark Effect ◽  
Optical Pumping ◽  
Laser Diodes ◽  
Wavelength Region ◽  
Green Laser ◽  
Research Field ◽  
Light Emitting ◽  
Quantum Confined Stark Effect ◽  
Semipolar Gan ◽  
First Time

AbstractTo achieve 520–532 nm green laser diodes (LDs), nonpolar and semipolar nitrides have attracted much attention because their usage leads to the elimination of the quantum-confined Stark effect and higher optical gains in this wavelength region. Since the breakthrough in the homoepitaxial growth technology for them, many nonpolar m -plane devices such as mW-class blue light-emitting diodes, violet 405 nm LDs, blue 460 nm LDs, and blue-green LDs beyond 490 nm have been announced. Advantages such as small blueshift and high slope efficiency (high output power to injected current ratio) have been confirmed for the first time in m -plane LDs beyond the blue region. On the other hand, the semipolar plane is also a candidate for green LDs. The pulsed operation of semipolar (1011) and (1122) violet LDs and lasing for a (1122) LD at 514 nm by optical pumping also have been reported. Such rapid progress in this research field will be reviewed.

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