scholarly journals A sensitive ultraviolet light photodiode based on graphene-on-zinc oxide Schottky junction

Nanophotonics ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 1073-1081 ◽  
Author(s):  
Teng-Fei Zhang ◽  
Guo-An Wu ◽  
Jiu-Zhen Wang ◽  
Yong-Qiang Yu ◽  
Deng-Yue Zhang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Potential Application ◽  
Schottky Barrier Height ◽  
Uv Light ◽  
Graphene Film ◽  
Optoelectronic Devices ◽  
Schottky Junction ◽  
Light Illumination ◽  
Good Reproducibility ◽  
Zno Nanostructure

AbstractIn this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.

scholarly journals Characteristics of Zn1-xAlxO NR/ITO Composite Films Oriented Application for Optoelectronic Devices

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Nguyen Dinh Lam
Keyword(s):  
Composite Film ◽  
Doping Concentration ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Composite Films ◽  
Optoelectronic Devices ◽  
Light Illumination ◽  
Electrical Characteristics ◽  
Al Doping ◽  
Vertical Resistance

The Zn1-xAlxO nanorod (NR) were grown on ITO substrates by a hydrothermal process. The influences of the Al doping concentration on the surface morphology, structural, optical, and electrical characteristics of the Zn1-xAlxO NR/ITO composite film were investigated in detail. The results indicated that characteristics of the Zn1-xAlxO NR/ITO composite film were strongly influenced by the Al doping concentration. Furthermore, the lowest vertical resistance of the Zn1-xAlxO NR can be obtained when x = 0.01 and it strongly reduces when the concentration of UV light illumination increases. This reduction follows an exponential decay with a decay rate of 4.35. This result shows good photoconductivity response of the Zn1-xAlxO NR/ITO composite film and its ability to apply for optoelectronic devices material.

scholarly journals Propeller-Shaped ZnO Nanostructures Obtained by Chemical Vapor Deposition: Photoluminescence and Photocatalytic Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. L. Wang ◽  
H. W. Zhu ◽  
W. H. Tang ◽  
P. G. Li
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Uv Light ◽  
Photocatalytic Property ◽  
Chemical Vapor ◽  
Structural Defects ◽  
Light Illumination ◽  
Zno Nanostructures ◽  
Zno Nanostructure ◽  
Vapor Deposition Technique

Propeller-shaped and flower-shaped ZnO nanostructures on Si substrates were prepared by a one-step chemical vapor deposition technique. The propeller-shaped ZnO nanostructure consists of a set of axial nanorod (50 nm in tip, 80 nm in root and 1 μm in length), surrounded by radial-oriented nanoribbons (20–30 nm in thickness and 1.5 μm in length). The morphology of flower-shaped ZnO nanostructure is similar to that of propeller-shaped ZnO, except the shape of leaves. These nanorods leaves (30 nm in diameter and 1–1.5 μm in length) are aligned in a radial way and pointed toward a common center. The flower-shaped ZnO nanostructures show sharper and stronger UV emission at 378 nm than the propeller-shaped ZnO, indicating a better crystal quality and fewer structural defects in flower-shaped ZnO. In comparison with flower-shaped ZnO nanostructures, the propeller-shaped ZnO nanostructures exhibited a higher photocatalytic property for the photocatalytic degradation of Rhodamine B under UV-light illumination.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

scholarly journals Deposition of Zinc Oxide Coatings on Wood Surfaces Using the Solution Precursor Plasma Spraying Process

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 183
Author(s):  
Ghiath Jnido ◽  
Gisela Ohms ◽  
Wolfgang Viöl
Keyword(s):  
Zinc Oxide ◽  
Ftir Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Color Change ◽  
Uv Light ◽  
Beech Wood ◽  
Nitrate Solution ◽  
Ftir Spectra ◽  
Solution Precursor ◽  
Wood Surfaces

In the present work, the solution precursor plasma spray (SPPS) process was used to deposit zinc oxide (ZnO) coatings on wood surfaces using zinc nitrate solution as precursor to improve the hydrophobicity and the color stability of European beech wood under exposure to ultraviolet (UV) light. The surface morphology and topography of the wood samples and the coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The formation of ZnO was detected with the help of X-ray photoelectron spectroscopy (XPS) and by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectra of the coated samples showed the typical Zn–O band at 445 cm−1. According to the XPS analysis, the coatings consist of two different Zn-containing species: ZnO and Zn(OH)2. Variation of the deposition parameters showed that the most significant parameters affecting the microstructure of the coating were the solution concentration, the deposition scan speed, and carrier gas flow rate. The wettability behaviors of the coated wood were evaluated by measuring the water contact angle (WCA). The coatings that completely covered the wood substrates showed hydrophobic behaviors. UV-protection of wood surfaces after an artificial UV light irradiation was evaluated by color measurements and FTIR spectroscopy. The ZnO-coated wood surfaces were more resistant to color change during UV radiation exposure. The total color change decreased up to 60%. Additionally, the FTIR spectra showed that the wood surfaces coated with ZnO had more stability. The carbonyl groups formation and C=C-bonds consumption were significantly lower.

scholarly journals A Study about Schottky Barrier Height and Ideality Factor in Thin Film Transistors with Metal/Zinc Oxide Nanoparticles Structures Aiming Flexible Electronics Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1188
Author(s):  
Ivan Rodrigo Kaufmann ◽  
Onur Zerey ◽  
Thorsten Meyers ◽  
Julia Reker ◽  
Fábio Vidor ◽  
...  
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Flexible Electronics ◽  
Thin Film Transistors ◽  
Zinc Oxide Nanoparticles ◽  
Schottky Barrier Height ◽  
Oxide Nanoparticles ◽  
Semiconductor Interfaces

Zinc oxide nanoparticles (ZnO NP) used for the channel region in inverted coplanar setup in Thin Film Transistors (TFT) were the focus of this study. The regions between the source electrode and the ZnO NP and the drain electrode were under investigation as they produce a Schottky barrier in metal-semiconductor interfaces. A more general Thermionic emission theory must be evaluated: one that considers both metal/semiconductor interfaces (MSM structures). Aluminum, gold, and nickel were used as metallization layers for source and drain electrodes. An organic-inorganic nanocomposite was used as a gate dielectric. The TFTs transfer and output characteristics curves were extracted, and a numerical computational program was used for fitting the data; hence information about Schottky Barrier Height (SBH) and ideality factors for each TFT could be estimated. The nickel metallization appears with the lowest SBH among the metals investigated. For this metal and for higher drain-to-source voltages, the SBH tended to converge to some value around 0.3 eV. The developed fitting method showed good fitting accuracy even when the metallization produced different SBH in each metal-semiconductor interface, as was the case for gold metallization. The Schottky effect is also present and was studied when the drain-to-source voltages and/or the gate voltage were increased.

Optimization of zinc oxide nanoparticle-catalyzed in vitro bilirubin photolysis and in vivo treatment of hyperbilirubinemia

Nanomedicine ◽  
2021 ◽  
Author(s):  
Haq Nawaz ◽  
Iqra Naseem ◽  
Tanzila Rehman ◽  
Mubashir Nawaz
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Uv Light ◽  
Uv Exposure ◽  
Uv Treatment ◽  
Blood Samples ◽  
Positive Effects ◽  
Oxide Nanoparticle

Aim: To optimize the Zinc oxide nanoparticles (ZnONPs)-catalyzed in vitro photolysis of bilirubin and to test their effect on bilirubin clearance in vivo. Materials & methods: ZnONPs, synthesized in an alkaline medium, were characterized. Response surface methodology was used to optimize the in vitro photolysis catalyzed by the nanoparticles (NPs). Blood samples from phenylhydrazine-induced hyperbilirubinemic rabbits which had been administered ZnONPs and UV light were analyzed to assess in vivo clearance of bilirubin. Results: The ZnONP-assisted UV treatment showed the linear and quadratic positive effects on the in vitro bilirubin photolysis with an optimal photolysis of bilirubin at 225 mg dl-1 concentration of ZnONPs and a UV exposure of 1.80 h. The ZnONP-assisted phototherapy of hyperbilirubinemic animals was also found to be more effective for in vivo clearance of bilirubin than phototherapy alone. Conclusion: After further trials, ZnONP-assisted phototherapy could be a potential treatment for hyperbilirubinemia in humans.

Optic and Piezoelectric Coupling in the Sol-Gel PLZT Electroceramics

2012 ◽  
Vol 730-732 ◽  
pp. 129-134
Author(s):  
Lucjan Kozielski ◽  
Malgorzata Plonska
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Light Illumination ◽  
Piezoelectric Effects ◽  
Piezoelectric Coupling ◽  
Wireless Device ◽  
Organometallic Precursors ◽  
Gain Adjustment ◽  
Piezoelectric Transformers ◽  
Sintering Method

PZT ceramic system with presence of La contents, have been proposed and prepared using sol gel sintering method for practical application of photostriction, which is the superposition of photovoltaic and piezoelectric effects. Such a ceramics produced by conventional mixing oxide method does not exhibit photostrictive properties due to the defects and inhomogeneous distribution of grains and pores. In this study, an investigated lanthanium(III) doped PZT ceramics were obtained by sol-gel technique from the organometallic precursors. It was found that fabricated material were effective in the enhancement of photovoltaic and photostrictive properties. Consequently, lanthanium influence deviation of piezoelectric parameters were studied as a function UV light illumination. For the determination lighting dependancy of the transformation parameters the resonant and antiresonant method was implemented. The improved Piezoelectric Transformer structure successfully changed gain characteristics proportionally to light intensity. The authors invention of a light driven output gain adjustment in Piezoelectric Transformers (PT) yields a novel “smart” multifunctional wireless device. This new created application area can be utilized in self-adopting shutters in photo cameras due to improved sensitivity to surrounding illumination conditions.

Research on Photochromic Compounds with Synthesis and Properties of a Novel Unsymmetrical Diarylethene with a Benzothiophene and a Pyrrole Group

2014 ◽  
Vol 1003 ◽  
pp. 23-26
Author(s):  
Hong Jing Jia ◽  
Ying Long Fu ◽  
Cong Bin Fan
Keyword(s):  
Thermal Stability ◽  
Potential Application ◽  
Uv Light ◽  
Optical Storage ◽  
Pmma Film ◽  
Good Thermal Stability ◽  
Photochromic Compounds ◽  
Storage Technology ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene1o, which is named [1-(2-methyl-benzothiophene)-2-(2-cyano-1,5-dimethyl-4-pyrryl)]perfluorocyclopentene, was synthesized. We used it to accomplish recording by optical storage technology as memory medium. Then its photochromic both in hexane solution and in PMMA film and kinetics experiment were investigated in detail. The result indicated that this diarylethene had good thermal stability and exhibited reversible photochromism, changing the color from colorless to violet in hexane solution upon appropriate irradiation with 297 nm UV light, respectively. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. The results demonstrated that the unsymmetrical diarylethene compound1o, which we have synthesized, had attractive properties for potential application in optical storage.

Sign in / Sign up

Export Citation Format

Share Document