scholarly journals Structural Characterization and Magnetic Properties of Undoped and Ti-Doped ZnO Nanoparticles Prepared by Modified Oxalate Route

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ekane Peter Etape ◽  
Josepha Foba-Tendo ◽  
Lambi John Ngolui ◽  
Beckley Victorine Namondo ◽  
Fomogne Cyrille Yollande ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Hexagonal Wurtzite Structure ◽  
Decomposition Products ◽  
Pure Zinc ◽  
Morphological Studies ◽  
Eds Analysis ◽  
Average Grain Size ◽  
Oxalate Route ◽  
Doped Zno ◽  
Zinc Oxalate

Ti-doped zinc oxide and pure zinc oxide nanoparticles were synthesized by a modified oxalate route using Averrhoa carambola fruit juice as a natural source of oxalate. The characteristics of the precursors have been investigated by FTIR, TGA, and XRD. The results from the investigation revealed that the precursors are zinc oxalate and Ti-doped zinc oxalate which readily decompose at 450°C. The as-prepared precursors were calcined at 450°C for 4 hours, and the decomposition products have been characterized by XRD, SEM, EDX, and VSM. XRD results revealed crystallinity with hexagonal wurtzite structure, while the average grain size was found to be 26 nm for Ti-doped ZnO and 29 nm for ZnO, using calculations based on Debye-Scherrer equation. Furthermore, the morphological studies by SEM showed particle agglomeration, while the presence of Ti3+ in the zinc oxide lattice is indicated by EDS analysis. Finally the hysteresis loop from VSM results shows that Ti-doped ZnO exhibits ferromagnetism.

scholarly journals Optical Properties of Sn Doped ZnO Thin Film Prepared Using Sol-Gel Method for Optical Limiting Application

2021 ◽  
Vol 24 (3) ◽  
pp. 38-42
Author(s):  
Marwa Mudfer Alqaisi ◽  
◽  
Alla J. Ghazai ◽  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Optical Properties ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Limiting ◽  
Pure Zinc ◽  
Gel Method ◽  
Sol Gel Method ◽  
Doped Zno

In this work, pure Zinc oxide and tin doped Zinc oxide thin films nanoparticles with various volume concentrations of 2, 4, 6, and 8V/V% were prepared by using the sol-gel method. The optical properties were investigated by using UV-Visible spectroscope, and the value exhibits the direct allowed transition. The average of transmittance was around ~(17-23) %in visible region. The optical energy band gap was calculated with wavelength (300-900) nm for pure ZnO and Sn doped ZnO thin films which decreases with increasing concentration from 3.4 eV to 3.1 eV respectively and red shift. The real dielectric(εr) and the imaginary dielectric εiare the same behavior of the refractive index(n) the extinction coefficient (k) respectively. The optical limiting properties were studied by using an SDL laser with a wavelength of 235 nm. ZnO and doping thin films an found efficient as optic limiting and depend on the concentration of the all samples.

scholarly journals Antimicrobial Bilayer Nanocomposites Based on the Incorporation of As-Synthetized Hollow Zinc Oxide Nanotubes

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 503 ◽  
Author(s):  
Carol López de Dicastillo ◽  
Cristian Patiño Vidal ◽  
Irene Falcó ◽  
Gloria Sánchez ◽  
Paulina Márquez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Morphological Structure ◽  
Specific Area ◽  
Hexagonal Wurtzite Structure ◽  
Atomic Layer ◽  
Average Diameter ◽  
Polymeric Coating ◽  
Morphological Studies ◽  
Antimicrobial Materials

An antimicrobial polymeric bilayer structure based on the application of an acrylic coating containing hollow zinc oxide nanotubes over a polymeric substrate was developed in this work. Firstly, zinc oxide nanotubes (ZnONT) were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers followed by polymer removal through calcination with the purpose of obtaining antimicrobial nanostructures with a high specific area. Parameters of electrospinning, ALD, and calcination processes were set in order to obtain successfully hollow zinc oxide nanotubes. Morphological studies through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopies confirmed the morphological structure of ZnONT with an average diameter of 180 nm and thickness of approximately 60 nm. Thermal and X-ray diffraction (XRD) analyses provided evidence that calcination completely removed the polymer, resulting in a crystalline hexagonal wurtzite structure. Subsequently, ZnONT were incorporated into a polymeric coating over a polyethylene extruded film at two concentrations: 0.5 and 1 wt. % with respect to the polymer weight. An antimicrobial analysis of developed antimicrobial materials was performed following JIS Z2801 against Staphylococcus aureus and Escherichia coli. When compared to active materials containing commercial ZnO nanoparticles, materials containing ZnONT presented higher microbial inhibition principally against Gram-negative bacteria, whose reduction was total for films containing 1 wt. % ZnONT. Antiviral studies were also performed, but these materials did not present significant viral reduction.

scholarly journals Performance Improvement of UV Photodetectors using Cd-doped ZnO Nanostructures

2021 ◽  
Author(s):  
Fatemeh Abbasi ◽  
Fahimeh Zahedi ◽  
Mohammad hasan Yousefi
Keyword(s):  
Morphological Characteristics ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Uv Photodetector ◽  
Pure Zinc ◽  
Current Time ◽  
X Ray ◽  
Metal Semiconductor Metal ◽  
Current Voltage ◽  
Doped Zno

Abstract The present research performed thermal decomposition to synthesize pure zinc oxide (ZnO) and cadmium-doped ZnO (ZnO:Cd) nanorods with ZnO to Cd weight ratios of 93:7, 95:5 and 97:3. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy were performed and current/voltage and current/time measured to determine the optical, structural and morphological characteristics of ZnO and ZnO:Cd. The XRD results suggested the hexagonal wurtzite structure of all the samples and the successful incorporation of Cd into the ZnO structures. This incorporation caused a spherical to rod-like change in the shape of the nanostructures. An intense and sharp peak was observed at 380 nm (3.26 eV) in the UV region of the PL spectra of all the samples. A UV photodetector fabricated on the basis of ZnO and ZnO:Cd nanorods with a metal-semiconductor-metal configuration showed the significant photocurrent and photosensitivity of the ZnO:Cd samples in the UV photodetection application. The sensitivity of the fabricated ZnO photodetectors with Cd percentages of 0, 3, 5 and 7% was respectively obtained as 110.62, 463.28, 762.40 and 920.30. The fastest photoresponse, with a rise and decay time of 2.5 and 4 s, respectively, was associated with the sample doped with 5% Cd.

scholarly journals Humidity Sensing Enhancement and Structural Evolution of Tungsten Doped Zinc Oxide Nano-Sensors Fabricated Through Co-Precipitation Synthesis

2021 ◽  
Author(s):  
Vernica Verma ◽  
Narendra Kumar Pandey ◽  
Priya Gupta ◽  
Kuldeep Singh ◽  
Peramjeet Singh
Keyword(s):  
Zinc Oxide ◽  
Crystallite Size ◽  
Structural Evolution ◽  
Hexagonal Wurtzite Structure ◽  
Morphological Properties ◽  
Aging Effects ◽  
Pure Zinc ◽  
Humidity Sensing ◽  
Nano Sensors ◽  
Co Precipitation

Abstract Nano-sensors samples of pure Zinc oxide and tungsten doped ZnO are employed for the study of their humidity sensing performance, morphological and micro-structural details. The nano-powder for sensors of ZnO1 − xWx (x = 0 to 1.75 mol%) are prepared in molar ratios of 0.50 mol%, 1.25 mol%, and 1.75mol% synthesized through co-precipitation technique. The effect of tungsten incorporation in 0.50 mol%, 1.25 mol% and 1.75 mol% on the structural and morphological properties of nanostructures has been investigated via XRD and SEM, respectively. The XRD of the synthesized ZnO nanomaterial possess hexagonal wurtzite structure for all the samples. The obtained diffractogram depicts high and broad peaks implying good crystallinity and smaller crystallite size. The molarity of the dopants yields sufficient reduction in crystallite size from 44.46 nm to 37.38 nm. The crystallite size of the samples calculated using W-H analysis yields 44.28 nm to 39.37 nm. The strain (ϵ) and stress (σ) produced in the crystal due to dopants is analyzed via USDM, UDEDM and SSP thereby deducing energy density ‘u’. The pelletized nano-sensors of diameter 10 mm and thickness 2 mm show excellent response towards humidity sensing within the range of 10–90% of relative humidity. An appreciable sensitivity of 144x and hysteresis of 8.24 is exhibited 1.75 mol% W-ZnO humidity sensor and good stability over a period of 270 days with minimum aging effects.

Low Temperature Deposition of Zinc Oxide Films

2003 ◽  
Vol 763 ◽  
Author(s):  
H. W. Lee ◽  
Y. G. Wang ◽  
S. P. Lau ◽  
B. K. Tay
Keyword(s):  
Zinc Oxide ◽  
Carrier Concentration ◽  
Vacuum Arc ◽  
Zno Films ◽  
Al Alloy ◽  
Pure Zinc ◽  
Zinc Oxide Films ◽  
Alloy Target ◽  
Temperature Deposition ◽  
Filtered Cathodic Vacuum Arc

AbstractA detailed study of zinc oxide (ZnO) films prepared by filtered cathodic vacuum arc (FCVA) technique was carried out. To deposit the films, a pure zinc target was used and O2 was fed into the chamber. The electrical properties of both undoped and Al-doped ZnO films were studied. For preparing the Al-doped films, a Zn-Al alloy target with 5 wt % Al was used. The resistivity, Hall mobility and carrier concentration of the samples were measured. The lowest resistivity that can be achieved with undoped ZnO films was 3.4×10-3 Ωcm, and that for Al-doped films was 8×10-4 Ωcm. The carrier concentration was found to increase with Al doping.

scholarly journals Sensing Performance of Al and Sn Doped ZnO for Hydrogen Detection

Proceedings ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 39
Author(s):  
Zahira. El khalidi ◽  
Maryam Siadat ◽  
Elisabetta. Comini ◽  
Salah. Fadili ◽  
Philippe. Thevenin
Keyword(s):  
Zinc Oxide ◽  
Chemical Sensor ◽  
Low Cost ◽  
Zinc Powder ◽  
Health Condition ◽  
Vibration Modes ◽  
X Ray Diffraction ◽  
Grain Sizes ◽  
Pure Oxide ◽  
Doped Zno

Chemical gas sensors were studied long ago and nowadays, for the advantageous role they provide to the environment, health condition monitoring and protection. The recent studies focus on the semiconductors sensing abilities, especially of non toxic and low cost compounds. The present work describes the steps to elaborate and perform a chemical sensor using intrinsic and doped semiconductor zinc oxide. First, we synthesized pure oxide using zinc powder, then, two other samples were established where we introduced the same doping percentage of Al and Sn respectively. Using low cost spray pyrolysis, and respecting the same conditions of preparation. The obtained samples were then characterized by X Ray Diffraction (XRD) that revealed the hexagonal wurzite structure and higher crystallite density towards the direction (002), besides the appearance of the vibration modes related to zinc oxide, confirmed by Raman spectroscopy. SEM spectroscopy showed that the surface morphology is ideal for oxidizing/reduction reactions, due to the porous structure and the low grain sizes, especially observed for the sample Sn doped ZnO. The gas testing confirms these predictions showing that the highest response is related to Sn doped ZnO compared to ZnO and followed by Al doped ZnO. The films exhibited responses towards: CO, acetone, methanol, H2, ammonia and NO2. The concentrations were varied from 10 to 500 ppm and the working temperatures from 250 to 500°C, the optimal working temperatures were 350 and 400 °C. Sn doped ZnO showed a high response towards H2 gas target, with a sensitivity reaching 200 at 500 ppm, for 400 °C.

Change in polarity of zinc oxide films grown on sapphire substrates without insertion of any buffer layer

2008 ◽  
Vol 23 (12) ◽  
pp. 3269-3272 ◽  
Author(s):  
Yutaka Adachi ◽  
Naoki Ohashi ◽  
Tsuyoshi Ohnishi ◽  
Takeshi Ohgaki ◽  
Isao Sakaguchi ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zno Films ◽  
Ion Scattering ◽  
Ceramic Target ◽  
Interfacial Phase ◽  
Sapphire Substrates ◽  
Zinc Oxide Films ◽  
Ion Scattering Spectroscopy ◽  
Doped Zno ◽  
Polarity Change

We have investigated the polarity of zinc oxide (ZnO) and Al-doped ZnO films grown on (11¯20) and (0001) sapphire substrates, using coaxial impact collision ion scattering spectroscopy. The films grown by pulsed laser deposition with a nominally undoped ZnO ceramic target had a (000¯1) surface, whereas the films prepared with a 1 mol% Al-doped ZnO ceramic target had a (0001) surface. The usage of Al-doped and undoped targets caused no difference in the in-plane lattice orientation. Electron microscope observations revealed that polarity change due to doping occurred without the formation of any interfacial phase between ZnO and sapphire.

Nonstoichiometric Zinc Oxide Nanorod Arrays Doped Co or Ni as Effective Antimicrobial Materials

2012 ◽  
Vol 518-523 ◽  
pp. 760-763
Author(s):  
Chang Yun Chen ◽  
Quan Zhan Chen ◽  
Mei Shi ◽  
Feng Zhou ◽  
Chun Hua ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zno Nanorod ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Functional Nanomaterials ◽  
Antimicrobial Materials ◽  
Doped Zno

Nonstoichiometric Zinc oxide (ZnO) nanorod arrays doped Co or Ni can be easily obtained by calicining soaked ZnO nanorod arrays. More importantly, the nonstoichiometric doped ZnO nanoarrays have more effective antimicrobial than pure ZnO nanoarrays, which means we can obtain a kind of promising new effective functional nanomaterials.

Structural and Optical Properties of F-Doped ZnO Nanoparticles Synthesized by Co-Precipitation Process

2016 ◽  
Vol 675-676 ◽  
pp. 69-72
Author(s):  
Krisana Chongsri ◽  
Wanichaya Mekprasart ◽  
Wisanu Pecharapa
Keyword(s):  
Zno Nanoparticles ◽  
Fluoride Concentration ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Ammonium Fluoride ◽  
Zinc Nitrate ◽  
Precipitation Process ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Co Precipitation

In this work, we reported the preparation of F-doped ZnO nanoparticles by facile precipitation process using zinc nitrate and ammonium fluoride as starting precursors for Zn and F, respectively dissolved in deionized water. The precursor solution was prepared at various fluoride composition ranging from 1-5 wt%. The as-precipitated powders were calcined at different temperature from 500 °C to 700 °C for 2 h. Effect of calcination temperature and fluoride concentration on structural, morphologies, optical and electrical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis spectroscopy, respectively. XRD results indicated the complete formation of hexagonal wurtzite structure of ZnO. SEM micrographs showed the agglomeration for each sample that noticeably influenced by fluoride content.

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