Properties Of Zinc Oxide Research Articles

Harnessing the Excellent Mechanical, Barrier and Antimicrobial Properties of Zinc Oxide (ZnO) to Improve the Performance of Starch-based Bioplastic

ABSTRACT The inherent properties of starch which are poor mechanical properties and its hydrophilicity that leads to poor long-term water absorption, fostered the incorporation of additives into starch-based bioplastic to enhance its mechanical and barrier properties. Zinc oxide (ZnO) nanoparticle as a lightweight material that is biocompatible, nontoxic, cost-effective and exhibit strong antibacterial activity can be considered as nano reinforcement of starch-based bioplastic. The present work studied the reinforcing effect of ZnO on the physical, mechanical and antibacterial properties of starch-based bioplastic. Bioplastic was prepared by melt-mixing starch and glycerol (3:1, w/w) with ZnO (1%, 2%, 3%, 4% and 5%, w/w). Bioplastic density and water contact angle increased with the increase of ZnO concentration. Bioplastic with the addition of 4% ZnO showed the lowest moisture content of 3.45%. Moreover, the decomposition temperature of bioplastic with ZnO increased slightly which indicated the higher stability. Mechanical properties evaluation showed that bioplastic with addition of ZnO had higher tensile strength than that without ZnO where 4% ZnO exhibited the highest tensile strength of 10.29 MPa with elongation of 5.69%. Cross-section microstructure after tensile test showed that ZnO was fairly dispersed in starch matrix that implied the increase of the mechanical properties of bioplastic. FTIR spectra exhibited that the intermolecular interaction in bioplastics occurred through C–H, C=O, C–O–H and O–H groups. In addition, biodegradability tests of bioplastic showed that the growth of microbes decreased in the presence of ZnO due to the nature of ZnO as an antibacterial compound. The results showed that ZnO played a key role in reinforcing the physical, mechanical and antibacterial properties of starch-based bioplastic.

Effect of processing temperature on film properties of ZnO prepared by the aqueous method and related organic photovoltaics and LEDs

The aqueous processed ZnO ETLs enable low-temperature, simple and green-strategy fabrication for efficient OPVs and OLEDs.

Manufacturing and characterization of ZnO and ZnO-doped frit crystal by physical and optical methods

This study was carried out to determine the physical and optical properties of zinc oxide (ZnO) and ZnO-doped Frit. Two groups of ZnO were prepared, namely, pure ZnO and ZnO-doped Frit. ZnO was prepared as ZnO disc and ZnO powder, and its high surface area and other characterized physical properties were expected to be the figure of merit in increasing the radiation interaction. Field emission scanning electron microscope and energy-dispersive X-ray (EDX) (FESEM) were utilized for analysis purposes. The particle size of pure ZnO was larger than ZnO-doped Frit in which ZnO-doped Frit particle size ranged in the scope of 260 nm, while pure ZnO was in the scope of 300 nm. The bond of the ZnO-doped Frit was better compared to pure ZnO. Raman spectroscopy characterization studies showed that the tops for both spectra displayed the same Raman shift. More top in ZnO-doped Frit was seen due to its bigger amount of impurities in the crystal. The energy gap for discs by UV of P338 was 3.37 eV, while the energy gap for ZnO-doped Frit was 3.26 eV. This study yielded impressive results in terms of the manufacture of ZnO, whereby the energy gap was proved by Ultraviolet–visible (UVV) device. In contrast, the ZnO-doped Frit generated inadequate result due to the small percentage used.

Oxygen effect on structural and optical properties of zinc oxide

ABSTRACTThis article deals with an investigation of the effect of oxygen content on optical and structural properties of ZnO films. Zinc oxide films were deposited with the DC reactive magnetron sputtering process on Si(100) and glass substrates. ZnO films were elaborated at different oxygen flow rates from (O2) 12 to 35 sccm. The evolution of optical and structural properties as a function of O2 was investigated by X-ray diffraction, Profilometer, Field Emission Scanning Electron Microscopy (FESEM) and ultraviolet–visible. By increasing O2, the crystallite size increases from 20 to 27 nm, which leads to an enlargement in the ZnO band gap from 3.18 to 3.30 eV. At 30 sccm of O2, the films present a significant improvement in the band gap (3.30 eV). The results reveal that with increasing O2, all films show a high crystallinity in the wurtzite phase and present a (002)ZnO preferential orientation along the c-axis. ZnO exhibited a good self-texture.

Nonlinear Optical Properties of Zinc Oxide Thin Films Produced by Pulsed Laser Deposition

Abstract In this work, the nonlinear optical properties of Zinc Oxide (ZnO) thin films produced on microscope slide glass substrates at room temperature (RT) using Pulsed Laser Deposition (PLD) method has been presented. PLD system consists of a vacuum chamber (pumped by a turbo molecular pump, backed with a rotary pump), rotating sample and substrate holders, optical thickness measurement system, infrared temperature measurement system and a nanosecond laser system. Previously deposition vacuum chamber evacuated down to ∼10-8 mbar and deposition was taken place about 1.3×10-1 mbar oxygen background gas pressure value. Morphological properties of thin films were obtained by Atomic Force Microscopy (AFM) that shows homogenous and smooth film structure. Thin films crystallinity were investigated by using X-Ray Diffraction (XRD) method and showed that polycrystalline ZnO structure with the largest peak corresponding to (002) orientation but some films contain Zn with (101) orientation . The thicknesses of the films were deduced from reflectance measurement using a fitting software and crosschecked with profilometer and AFM measurements. The thickness of the films ranged between 10 nm and 220 nm. Linear optical properties were obtained by using UV-VIS Spectrometer. Furthermore, we presented the nonlinear optical properties of the ZnO thin films that were obtained by the z-scan method

Excitons in ZnO Quantum Wells

Reflectance and photoluminescence spectra of the ZnO/Zn0.78Mg0.22O structures with ZnO quantum wells and thick ZnO and Zn0.78Mg0.22O layers have been thoroughly investigated at different temperatures and excitation intensities and wavelengths. All the observed spectral lines have been identified. It has been established that the built-in electric field does not affect the spectrum as strongly as was expected. The built-in field is apparently effectively screened by the carriers that have migrated to the bands from donor and acceptor levels. The parameters determining the exciton properties in zinc oxide have been estimated.

Capacitive properties of zinc oxide thin films by radiofrequency magnetron sputtering

The study focused on the production of zinc oxide (ZnO) thin films as a dielectric material for use in metal–insulator–semiconductor capacitors. The objective of this study has demonstrated the frequency dependence of conductivity and capacity. Zinc oxide (ZnO) was thin films deposited by a silicon wavelength sputtering\\magnetron cathode sputtering. The capacitive properties of ZnO zinc oxide were studied at room temperature. The frequency dependence of the conductivity, capacitance and the measured current–voltage (I–V) characteristics of ZnO zinc oxide thin films were studied in the frequency range from 5 kHz to 13 MHz. It is shown that the conductivity is total. Indeed, the measurement of the conductivity in alternating regime obeys the Arrhenius equation. In addition, the measured I–V characteristics of the structures studied at 10 kHz and 10 MHz clearly revealed areas of accumulation, depletion and inversion in the plots. It has been observed that AC conductivity and capacity in the ZnO thin films (ZnO) are frequency dependent. This dependence indicates that the conduction is thermally activated and maintains the correlated barrier of the charge carrier on the localized states as a function of the experimental data. The FBAR (expand) devices with the ZnO films exhibited a pronounced resonance peak centered at 537 MHz with a k2 coupling coefficient of 7%. It found therefore that the impedance matching of the FBAR could be easily achieved simply by controlling the resonance the resonator.

Fabrication and characterization of c-Si/porous-Si/CdS/ZnxCd1-xO heterojunctions for applications in nanostructured solar cells

Solar cells based on c-Si/porous-Si/CdS/ZnxCd1-xO heterojunctions were synthesized by depositing CdS films on c-Si/porous-Si (PS) substrates by electrochemical deposition (ED). PS layers with systematically varied pore diameter (8-45 nm) and were fabricated on p-type c-Si wafers using electrochemical etching. The window layers of ZnxCd1-xO with several Zn concentrations(x=0.2; 0.4; 0.5 and 0.6) were also deposited on the CdS buffer layers by ED. The photoelectrical properties of heterojunctions were studied as functions of PS pore size and Zn content in ZnxCd1-xO. The optimal pore size and Zn contents were found to be 10 nm and x=0.6, respectively. These yielded a solar cell sample exhibiting an efficiency of 9.9%, the maximum observed in this study. Full Text: PDF ReferencesM.A.Green. "Limiting efficiency of bulk and thin-film silicon solar cells in the presence of surface recombination", Progress in Photovoltaic 7, 327 (1999). CrossRef P.Papet, O. Nichiporik, A. Kaminski et al. "Pyramidal texturing of silicon solar cell with TMAH chemical anisotropic etching", Solar Energy Materials and Solar Cells 90, 2319 (2006). CrossRef P. Vitanovet et al. "High-efficiency solar cell using a thin porous silicon layer", Thin Solid Films 297, 299 (1997). CrossRef L. Santinacci et al. "Electrochemical and optical characterizations of anodic porous n-InP(1 0 0) layers", Electrochim. Acta 56, 878 (2010). CrossRef V.Lehmann. "The Physics of Macropore Formation in Low Doped n‐Type Silicon", J. Electrochem. Soc. 140, 2836 (1993). CrossRef Bisi O et al. "Porous silicon: a quantum sponge structure for silicon based optoelectronics", Surface Science Reports 38, 1 (2000). CrossRef A.I. Raid et al. Applied Nanoscience 7, 9 (2016). CrossRef M.A. Naser et al. "Characteristics of Nanostructure Silicon Photodiode using Laser Assisted Etching", Procedia Engineering 53, 393 (2013). CrossRef D.H. Oh et al. J. Ceram. Process. Res. "Effects of a H2SO4 treatment on the optical properties in porous Si layers and electrical properties of diode devices fabricated with a H2SO4 treated porous Si layer", 9, 57 (2008). DirectLink H. Foll et al. "Formation and application of porous silicon", Materials Science and Engineering R 280, 1 (2002). CrossRef P. Granitzer et al. "Porous Silicon—A Versatile Host Material", Materials 3, 943 (2010). CrossRef G. Korotcenkov, Porous Silicon: From Formation to Application (Taylor and Francis Group, CRC Press, Boca Raton, USA, 2016). DirectLink V.Y. Yerokhov. "Porous silicon in solar cell structures: a review of achievements and modern directions of further use", Renewable and Sustainable Energy Rev. 3, 291 (1999). CrossRef A. Ramizy et al. "New optical features to enhance solar cell performance based on porous silicon surfaces", Appl. Surf. Science 257, 6112 (2011). CrossRef F. Ruske et al. "Large area ZnO:Al films with tailored light scattering properties for photovoltaic applications", Thin Solid Films 515, 8695 (2007). CrossRef Y. Alivov et al. "Observation of 430 nm electroluminescence from ZnO/GaN heterojunction light-emitting diodes", Appl. Phys. Lett. 83, 2943 (2003). CrossRef G.V. Lashkarev et al. "Properties of zinc oxide at low and moderate temperatures", Low Temp. Phys. 37, 289 (2011). CrossRef P.M. Devshette et al. "Growth and physical properties of ZnxCd1−xO thin films prepared by spray pyrolysis technique", J. of Alloys and Compunds 463, 576 (2008). CrossRef Y. Caglar et al. "Morphological, optical and electrical properties of CdZnO films prepared by sol–gel method", J. Phys. D: Appl. Phys. 42, 065421 (2009). CrossRef A. Abdinov et al. "Photosensitivity of p,n-Si/n-Cd1−xZnxS heterojunctions manufactured by a method of electrochemical deposition", Thin Solid Films 480-481, 388 (2005). CrossRef A Abdinov et al. "Investigation of electrodeposited p-Si/Cd1 − xZnxS1 − ySey heterojunction solar cells", Thin Solid Films 511-512,140 (2006) CrossRef J.B. Orhan et al. "Nano-textured superstrates for thin film silicon solar cells: Status and industrial challenges", Sol. Cells 140, 344 (2015). CrossRef H.Ch. Alan et al. "Light management of tandem solar cells on nanostructured substrates", J. Photon. Energy 7, 027001 (2017) CrossRef

Synthesis of ZnO Nanoparticle and Evaluation of its Potential to Enhance the Activity of Antibiotics

The properties of zinc oxide (ZnO) vary with its crystallite size or particle and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electron structure. This paper aims at synthesizing nanosized ZnO particles and the evaluation of its potential to enhance the activity of antibiotics. ZnO is prepared by using both hydrothermal and solvothermal methods. The sample was characterized by X-Ray Diffraction (XRD). The nanosize of particles was further confirmed by using TEM studies. The average crystal size of the prepared ZnO nanoparticles was determined by TEM. The synthesized nanoparticle was used to enhance the antibacterial efficacy of antibiotics such as Ampicillin and Streptomycin. It was found effective in both drugs against the clinically important bacterial strains tested. Drug resistance is an emerging crisis and becoming a menace to the public. As the bacterial strains showing antibiotic resistance are escalating day by day, application of these nanoparticles that enhance the antibacterial property will be promising for the development of new drugs.

Electrical and sensory properties of zinc oxide – porous silicon nanosystems

Zinc oxide nanostructures have been grown by electrochemical deposition on porous silicon–silicon substrate. The photoelectric and sensory properties of the obtained ZnO–porous silicon nanosystems were investigated in both DC and AC regimes. The obtained structures were characterized by photosensitivity in the 400–1100 nm wavelength range and by high sensitivity to moisture. Increase of relative humidity resulted in significant decrease of the electrical resistance and increase of the capacitance of the hybrid structures. To estimate the sensory properties of the ZnO–porous silicon nanostructures their adsorption sensitivity and dynamic characteristics were analyzed. Discovered features of the charge transport processes broaden the prospects of the semiconductor nanosystems application in gas sensors and photodetectors.

Preparation and properties of pulp fibers treated with zinc oxide nanoparticles by in situ chemosynthesis

Abstract The efficiency of the growth and properties of zinc oxide (ZnO) nanoparticles (ZnO-NPs) on pulp fibers was investigated. ZnO-NPs were grown on pulp fiber surface via an in situ chemosynthesis method at different concentrations. The modified pulp fibers were characterized by different analytical tools including field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray power diffraction (XRD) and thermogravimetric (TG) analysis. Ultraviolet (UV) absorption and antibacterial properties of the paper made from treated and untreated pulp fibers were analyzed. The results revealed that the rod-like ZnO-NPs were successfully grown onto the fiber surfaces without aggregation. As the precursor concentration increased from 0.01 to 0.07 mol l−1, the ZnO loading on the fibers increased from 4.2 to 23.4%, respectively. Compared to the untreated fibers, paper made from ZnO-treated fibers had a better UV absorption ability and antimicrobial effect against Escherichia coli and Staphylococcus aureus. However, the ZnO-treated pulp fiber reduced the zero span tensile index of the paper.

The Sputter Time Duration Effect on the Structural and Optical Properties of Zinc Oxide by RF Magnetron Sputtering

Nanocrystalline ZnO thin films have been fabricated by an RF magnetron sputtering method for the different time duration. The effect of process parameters on the structural, morphological and Optical properties of ZnO were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Photoluminescence and UV-Vis. Spectrometer. All of the films were polycrystalline, and the preferred crystal plane orientation was (101) corresponding to 2𝜃 = 36.57∘, the crystallite sizes were increased from 12 nm to 18 nm as in XRD calculations and increase from 24nm to 33 nm as in SEM image. Optical constants, such as refractive index n, were determined from the transmittance spectrum in the ultraviolet -visible. The refractive index varies in the range of 1.664 to 8.706 with an increase in deposition time. Optical energy gap estimated from the transmittance (3.304 eV) and the PL (3.44 eV) shows good agreement and increased as the time duration was increased.

Экситоны в квантовых ямах на основе ZnO

AbstractReflectance and photoluminescence spectra of the ZnO/Zn_0.78Mg_0.22O structures with ZnO quantum wells and thick ZnO and Zn_0.78Mg_0.22O layers have been thoroughly investigated at different temperatures and excitation intensities and wavelengths. All the observed spectral lines have been identified. It has been established that the built-in electric field does not affect the spectrum as strongly as was expected. The built-in field is apparently effectively screened by the carriers that have migrated to the bands from donor and acceptor levels. The parameters determining the exciton properties in zinc oxide have been estimated.

The Effects of Deposition Time and Seed Layer on Morphological Properties of Zinc Oxide by Chemical Bath Deposition

In this work, chemical bath deposition (CBD) method is used to form zinc oxide (ZnO) thin film nanostructures. Three types of zinc (Zn) precursors, namely Zn (NO3)2, ZnSO4 and ZnCl2, were used and the deposition time in water bath were controlled for 20, 40 and 60 minutes at 85 °C respectively. The effect of seed layer, by using potassium permanganate (KMnO4) solution, on the formation of zinc oxide (ZnO) thin films on glass substrates has been determined. It was found that the presence of the seed layer promote better adhesion of the films which allows ZnO to form with a higher growth rate on the substrate with only little or no loss by precipitation in the solution. The enhancement of the thin film adhesion is due to the in situ nucleation centres formation of hydrated oxide colloids of Mn (O)OH, acting as metal ion binding centres on the glass substrates surface. Meanwhile, in the absence of a seed layer, only scattered ZnO deposits are formed on substrates. By varying the deposition time, ZnO nanostructures with different length and diameter can be formed.

Preliminary study on the properties of zinc oxide (ZnO) for alpha particles detection

Preliminary study on the properties of zinc oxide (ZnO) for alpha particles detection

Characteristics of Elevated-Metal Metal-Oxide Thin-Film Transistors Based on Indium-Tin-Zinc Oxide

Based on the distinct effects of oxidizing thermal annealing on the properties of zinc oxide and indium-gallium-zinc oxide (IGZO) under covers of different gas-permeabilities, the elevated-metal metal-oxide (EMMO) thin-film transistor (TFT) architecture has been proposed and demonstrated using IGZO as the channel material. However, the speculation that the EMMO architecture is more generally applicable to semiconducting metal oxides other than IGZO has yet to be verified. Presently reported is an EMMO TFT with a modified structure employing indium-tin-zinc oxide as the channel material. The resulting TFT exhibited good performance metrics: a relatively higher field-effect mobility of 23.2 ± 0.8 cm2/Vs, an ON/OFF current ratio of at least $3.1\times 10^{10}$ , a pseudo subthreshold slope of 165 ± 15 mV/decade, a width-normalized off-state current of at most $8.1\times 10^{-19}\text{A}/\mu \text{m}$ , and robust stability against gate-bias stress.

Zinc Oxide Nanorod Growth on Au-coated Silverwire

In this study, zinc oxide nanostructures were grown on gold-coated silver wires by hydrothermal method. Multiple analyses on these nanostructures were performed to understand the structure and optical properties of zinc oxide on Au-plated silver wires, Owing to the Au-coated layer, ZnO nanorods could appear rather than ZnO nanoflakes on pure silver wires. Moreover, The deposited gold layer could vary zinc oxide nanostructures to nanorods The multiple analysis shows that lying flat ZnO structures with weak (002) crystalline structures and more defects could appear on the silver wire rather than ZnO nanostructures on pure silver wires.

Property of Zinc Oxide (Zno) Nanostructures Potential for Biomedical System and Its Common Growth Mechanism

Zinc Oxide (ZnO) nanomaterials have received broad attention thanks to their distinguished performance in electronics, optics and photonics. Due to the novel applications in optoelectronics, sensors, transducers and biomedical sciences, ZnO materials have become a leading edge in nanotechnology. Therefore, the properties of ZnO nanostructures potential for applying in biotechnology are marked along with the relevant common growth mechanism aim to provide the vital information about the growing field related to nano-ZnO in the biomedical system with environmental friendly nature and biocompatibility

Schottky Diodes on ZnO Thin Films Grown by Plasma-Enhanced Atomic Layer Deposition

Enhancement of the properties of zinc oxide (ZnO)-based Schottky diodes has been explored using a combination of plasma-enhanced atomic layer deposition (PE-ALD) ZnO thin films and silver oxide Schottky contacts deposited by reactive radio-frequency sputtering. The electrical properties of the ZnO thin films were systematically tuned by varying the deposition temperature and oxygen plasma time during PE-ALD to optimize the performance of the diode. Low temperature (80 °C) coupled with relatively long oxygen plasma time (>30 s) PE-ALD is the key to produce ZnO films with net doping concentration lower than 1017 cm−3. Under the optimal deposition conditions identified, the diode shows an ideality factor of 1.33, an effective barrier height of 0.80 eV, and an ON/OFF ratio of ${3.11} \times {10}^{{5}}$ .

Effect of Annealing on the Thermoluminescence Properties of ZnO Nanophosphor

We report the effect of annealing on the thermoluminescence (TL) properties of zinc oxide (ZnO) nanophosphor. The sample was synthesised by a wet chemical process. The characterisation report shows that the size of the grains is within 123.0 nm–160.5 nm. TL measured at 2 K/s from a fresh un-annealed sample irradiated to 60 mGy shows a composite glow curve containing three peaks at 353.2 K, 429.1 K, and 455.3 K. On the other hand, samples annealed at 473 K and 573 K followed by irradiation to 60 mGy do not give TL. However, annealing at 673 K and 773 K followed by irradiation to the same dose produces a glow curve comprising two overlapping peaks at 352.3 K and 370.6 K. In the TL emission spectrum of un-annealed sample, two emission peaks were found in green (~523 nm) and orange (~620 nm) regions whereas in annealed samples, only a peak was found in the orange region (~618 nm). Kinetic analysis shows that the activation energy corresponding to TL peaks at 353.2 K, 429.1 K, and 455.3 K of the un-annealed sample are 0.64 eV, 0.80 eV, and 1.20 eV whereas that of the peaks at 352.3 K and 370.6 K of 673 K and 773 K annealed samples are 0.64 eV and 0.70 eV, respectively. All peaks of un-annealed and annealed samples, except the one at 429.1 K of the un-annealed sample, follow first-order kinetics whereas the peak at 429.1 K follows second-order kinetics. Considering the kinetic and spectral features, an energy band model for ZnO nanophosphor has been proposed.