Up to 30 times enhancement of deep UV emission at room temperature by prolonged excitation of localized exciton in NaCl:I crystal

2009 ◽  
Vol 6 (1) ◽  
pp. 342-345 ◽  
Author(s):  
Ikuko Akimoto ◽  
Masahiro Shimozato ◽  
Ken-ichi Kan'no
Keyword(s):  
Room Temperature ◽  
Uv Emission ◽  
Deep Uv

Deep-UV emission at 260 nm from MBE-grown AlGaN/AlN quantum-well structures

2019 ◽  
Vol 512 ◽  
pp. 213-218 ◽  
Author(s):  
Wenxian Yang ◽  
Yukun Zhao ◽  
Yuanyuan Wu ◽  
Xuefei Li ◽  
Zhiwei Xing ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Well Structures ◽  
Uv Emission ◽  
Deep Uv

Intrinsic n- and p-Type MgZnO Nanorods for Deep-UV Detection and Room-Temperature Gas Sensing

2015 ◽  
Vol 119 (52) ◽  
pp. 29186-29192 ◽  
Author(s):  
Ruey-Chi Wang ◽  
Yu-Xian Lin ◽  
Jia-Jun Wu
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Uv Detection ◽  
Deep Uv ◽  
P Type

MORPHOLOGY CONTROLLING AND OPTICAL CHARACTERIZATION OF ZnO NANOMATERIALS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3635-3639
Author(s):  
YUZHEN LV ◽  
CHUNPING LI ◽  
PING CHE ◽  
LIN GUO ◽  
HUIBIN XU
Keyword(s):  
Room Temperature ◽  
Optical Characterization ◽  
Visible Emission ◽  
Ultraviolet Emission ◽  
Synthetic Process ◽  
Uv Emission ◽  
Zno Nanomaterials ◽  
Solution Route ◽  
Pl Spectrum

Wurtzite ZnO nanomaterials including nanoparticles, nanocolumns and nanorods were successfully synthesized by a solution route. Concentrations of modifying reagent and differences of solvent employed in the synthetic process can effectively adjust the morphologies of the as-grown products. Photoluminescence measurements of the ZnO nanocolumns and nanorods have been carried out at room temperature. A sharp Ultraviolet emission at 386 nm and a weak visible emission centered at 515 nm were observed in the PL spectrum of the nanocolumns, while a UV emission of the nanorods was observed at 377 nm.

Fabrication of ZnO Nanowall-Based Hydrogen Gas Nanosensor

2013 ◽  
Vol 684 ◽  
pp. 21-25 ◽  
Author(s):  
Tse Pu Chen ◽  
Sheng Po Chang ◽  
Shoou Jinn Chang
Keyword(s):  
Seed Layer ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Hydrogen Gas ◽  
Two Dimensional ◽  
Defect Related Emission ◽  
Room Temperature Photoluminescence ◽  
Hydrogen Sensing ◽  
Uv Emission ◽  
Sensing Characteristics

Two-dimensional ZnO nanowalls were rapidly grown on glass substrate by thermal evaporation at low temperature without any catalysts or the pre-deposition of a ZnO seed layer on the substrate. Most of the ZnO nanowalls grown at 450°C were vertical on substrate and they were about 70-200 nm thick and 2 µm long. The room-temperature photoluminescence (PL) spectra showed a strong intrinsic ultraviolet (UV) emission and a weak defect-related emission. Hydrogen-sensing characteristics of the ZnO nanowalls have been investigated, and that make them become attractive candidates for gas sensor.

scholarly journals Gas Detection Using Portable Deep-UV Absorption Spectrophotometry: A Review

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5210 ◽  
Author(s):  
Sulaiman Khan ◽  
David Newport ◽  
Stéphane Le Calvé
Keyword(s):  
Gas Sensing ◽  
Low Cost ◽  
Absorption Spectrometry ◽  
Optical Filters ◽  
Uv Absorption ◽  
Uv Photodetectors ◽  
Absorption Spectrophotometry ◽  
Uv Emission ◽  
Selective Approach ◽  
Deep Uv

Several gas molecules of environmental and domestic significance exhibit a strong deep-UV absorption. Therefore, a sensitive and a selective gas detector based on this unique molecular property (i.e., absorption at a specific wavelength) can be developed using deep-UV absorption spectrophotometry. UV absorption spectrometry provides a highly sensitive, reliable, self-referenced, and selective approach for gas sensing. This review article addresses the recent progress in the application of deep-UV absorption for gas sensing owing to its inherent features and tremendous potentials. Applications, advancements, and challenges related to UV emission sources, gas cells, and UV photodetectors are assessed and compared. We present the relevant theoretical aspects and challenges associated with the development of portable sensitive spectrophotometer. Finally, the applications of UV absorption spectrometry for ozone, NO2, SO2, and aromatic organic compounds during the last decades are discussed and compared. A portable UV absorption spectrophotometer can be developed by using LEDs, hollow core waveguides (HCW), and UV photodetectors (i.e., photodiodes). LED provides a portable UV emission source with low power input, low-intensity drifts, low cost, and ease of alignment. It is a quasi-chromatic UV source and covers the absorption band of molecules without optical filters for absorbance measurement of a target analyte. HCWs can be applied as a miniature gas cell for guiding UV radiation for measurement of low gas concentrations. Photodiodes, on the other hand, offer a portable UV photodetector with excellent spectral selectivity with visible rejection, minimal dark current, linearity, and resistance against UV-aging.

ZnO Nanostructures Obtained by Mist-Atomization Method Growth on Different Au-Seeded Substrates Temperature

2015 ◽  
Vol 1109 ◽  
pp. 603-607
Author(s):  
A.N. Afaah ◽  
N.A.M. Asib ◽  
Aadila Aziz ◽  
M. Rusop ◽  
Ruziana Mohamed ◽  
...  
Keyword(s):  
Glass Substrate ◽  
Room Temperature ◽  
Nitrate Solution ◽  
Zinc Nitrate ◽  
Morphological Properties ◽  
Nitrate Hexahydrate ◽  
Zno Nanostructures ◽  
Glass Substrates ◽  
Uv Emission ◽  
Surface Morphologies

Mist-atomization deposition method was applied in order to grow ZnO nanostructures with various surface morphologies. ZnO was deposited from the mixture of zinc nitrate hexahydrate (Zn (NO3)2.6H2O) and stabilizer, hexamethylenetetramine (HMTA, C6H12N4) aqueous solutions onto Au-seeded glass substrate. The mixture was sprayed onto the surface of Au-seeded glass substrate at various growth temperatures of room temperature (RT), 100, 200, and 300 °C. The obtained structures were characterised by room-temperature photoluminescence (PL), field emission scanning electron microscopy (FESEM), and UV-VIS-NIR spectrophotometer. It is found that ZnO growth on 300 °C substrate temperature shows the best absorbance properties and highest UV emission peak with denser distribution amongst all. The optical and morphological properties of sprayed ZnO nanostructures largely depend on the substrates temperature during spraying the zinc nitrate solution and on the Au-seeded glass substrates.

scholarly journals Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

2011 ◽  
Vol 133 (43) ◽  
pp. 17257-17261 ◽  
Author(s):  
Francesc Sastre ◽  
Vicente Fornés ◽  
Avelino Corma ◽  
Hermenegildo García
Keyword(s):  
Room Temperature ◽  
Uv Photolysis ◽  
Temperature Transformation ◽  
Deep Uv

Effect of O2 Flow Rate on the Morphological and Optical Properties of ZnO Nanocrystals

2012 ◽  
Vol 554-556 ◽  
pp. 70-75
Author(s):  
Hui Juan Tian ◽  
Jun Bo Xu ◽  
Ya Jun Tian ◽  
Hao Wen
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Morphological Evolution ◽  
Zno Nanorods ◽  
Dynamics Simulation ◽  
Flow Rates ◽  
Uv Emission ◽  
Zno Nanocrystals ◽  
Vapor Partial Pressure ◽  
Axial Growth

The morphological and optical properties of ZnO nanocrystals prepared by thermal evaporation of Zn powders were studied at both upstream and downstream under different O2flow rates. The morphological evolution was observed by scanning electron microscopy. With O2flow rates changing from 0.25 sccm to 1 sccm, the caps of the ZnO nanonails become bigger and the stems gradually disappear at upstream, and the diameters at the top of ZnO nanorods become thicker and the length become longer at downstream. Room temperature PL study shows that UV emission is relatively enhanced with increasing O2flow rates. Computational fluid dynamics simulation was performed, which indicates that the morphological evolution of the ZnO structures results from the competition between the axial growth and the radial growth based on different O2and Zn vapor partial pressure.

EFFECT OF W-DOPING ON MORPHOLOGY, STRUCTURAL AND OPTICAL PROPERTIES OF ZnO NANOSTRUCTURES SYNTHESIZED VIA THERMAL EVAPORATION

2012 ◽  
Vol 26 (27) ◽  
pp. 1250176 ◽  
Author(s):  
HOSEIN ESHGHI ◽  
YASER ARJMAND
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
Hexagonal Structure ◽  
Zno Nanostructures ◽  
Structural And Optical Properties ◽  
Thermal Evaporation Method ◽  
Violet Emission ◽  
Pl Spectra ◽  
Uv Emission ◽  
Oxygen Gas

Undoped and W -doped ZnO nanostructures were prepared by heating Zn and WO 3 powders in the presence of oxygen gas without any catalyst, using the thermal evaporation method at 950°C. Samples were characterized by FESEM images, also EDS, XRD and PL spectra. FESEM images showed the formation of nanowires in the undoped sample and porous nanostructures as flat-surface granules with various sizes in the doped samples. XRD spectra of the samples confirmed the formation of wurtzite hexagonal structure with (002) as the preferred orientation, while its intensity has reduced as the doping concentration has increased. Meanwhile, the room temperature PL spectra have indicated this variation is in conjunction with the reduction in the intensity of UV emission and appearance of a violet emission at 420 nm (2.95 eV).

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