Structure Properties Of ZnO Research Articles

Green synthesis of ZnO photocatalyst composited carbon quantum dots (CQDs) from lime (Citrus aurantifolia)

Lime (Citrus aurantifolia) is one of the most extensively exported agricultural products from Indonesia. Citric acid and ascorbic acid content from limes (Citrus aurantifolia) is such one of the carbon-rich fruits that is a suitable source for Carbon Quantum Dots (CQDs) synthesis. CQD synthesized by relying on natural carbon precursors from lime (Citrus aurantifolia) is a more environmentally friendly approach in the present research, CQDs in this research will be used as an addition to ZnO by hydrothermal method in order to enhance photocatalytic activity. Corresponding to the results, the presence of CQDs improves both the optical and structural properties of ZnO, which led to enhance photocatalytic activity with a degradation percentage of 98% shortly after 75 min of visible light irradiation and to each of the repeatability test cycle results showing the consistent results and with the rate constant (k) fluctuating and the specified compound's degradation percentage remains relatively constant with minor changes.

Effect of PEG-400 on the ZnO morphology activated by gamma rays in the realization of gas sensors

This work focuses on the preparation of ZnO nanostructures using a PEG-4000 catalyst. Zinc acetate is precipitated to form zinc hydroxide, which is then subjected to various analysis techniques including FTIR transmission spectra, SEM, UVvisible spectrophotometry, and X-ray diffraction (XRD) to study the morphological and structural properties of ZnO. The samples are exposed to different doses of radiation from a 60Co gamma source, ranging from 50 to 600 kGy. Thermal analysis (TGA and DSC) confirms the thermal stability of the ZnO nanostructures. Electrical characteristics are evaluated through AC impedance measurements, which reveal that the amount of charge carriers in ZnO films increases linearly with gamma radiation. The study also investigates the potential use of irradiated nanorod and spherical ZnO samples for the detection of butane gas. At a radiation dosage of 150 kGy, the gamma-ray-irradiated sensors exhibit increased butane responses of 66.73% and 69% for nanorod and spherical samples, respectively. The findings suggest that gamma irradiation can effectively modify materials and enhance their gas sensing properties.

Structural Properties of Cu-Doped ZnO Prepared by Coprecipitation Method

An experimental study to determine the effect of Cu doping on structural properties of ZnO nanoparticle has been conducted. Zn1-xCuxO (CZO) were prepared by co-precipitation method by varying Cu concentration with x = 0.00, 0.10, 0.11 and 0.12. The structural properties of the CZO sample were characterized by X-Ray diffraction (XRD) and X-ray Absorption Spectroscopy (XAS), which consist of XANES (X-ray Absorption Near-Edge Spectroscopy) and EXAFS (Extended X-ray Absorption Fine Structure). XAS measurements were performed in the energy of Cu K-edge and Zn K-edge using synchrotron radiation at SLRI (Synchrotron Light Research Institute) in Thailand. Both Cu K-edge and Zn K-edge XANES spectra indicate that the oxidation states of Cu and Zn ions are 2+. Analysis of XRD data with refinement method using Rietica software confirms the presence of Cu as doping in ZnO host lattice with the crystallite size ranging between 26 and 44 nm. Moreover, it shows that the obtained CZO samples are polycrystalline with (002) predominant reflection and exhibit a hexagonal wurtzite structure.

Effect of pulsed laser annealing on optical and structural properties of ZnO:Eu thin film

ZnO:Eu thin film fabricated by pulsed laser deposition was treated by pulsed UV laser. The effect of laser fluence from 70 to 125 mJ cm−2 on film properties was investigated. The results showed that the surface morphology was clearly modified and the film treated at laser fluence of 70 mJ cm−2 was more densified compared to the other annealed films. Laser treatment led to a reduction of carbon content and to a stoichiometric ZnO:Eu composition on the surface. Refractive index significantly decreased and extinction coefficient was blue shifted for higher laser fluences. Strong characteristic Eu3+ transitions were obtained using excitation at 266 nm. The highest photoluminescence intensity was observed for the annealed film at a laser fluence of 70 mJ cm−2. The influence of ambient composition (N2 and O2) and temperature (room temperature and 150 °C) to photoluminescence response was examined for optical gas sensor application. The laser-untreated film showed higher sensitivity to the presence of oxygen at both temperatures compared to the treated film. The stability of photoluminescence intensity at elevated temperature was improved for laser-treated areas.

Ordering mechanism of silver nanoparticles synthesized in a ZnO:Al polycrystalline film by sol gel method

The optical absorption spectra and structural properties of ZnO:Al films with an intermediate layer of silver nanoparticles with a different number of inserted layers of silver nitrate solution are studied. The study of optical properties showed that with an increase in the number of layers, the intensity of the plasmon absorption peak of nanoparticles increases. Consequently, with an increase in the number of layers, their density increases, it was confirmed by studies of the obtained samples structural properties by transmission electron microscopy.

Structural parameters of hydrothermally synthesized ZnO nanostructure and their based solar cells

ZnO nanostructure (NS) were prepared via hydrothermal route at various times of heat treatment. The structural properties of ZnO (NS) were reported using X-ray diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HR-TEM). The obtained XRD peaks matched with the standard hexagonal wurtzite crystal structure of ZnO ((ICSD) No. 067454)). Additionally, no noticed peaks corresponded to any phase. The crystal structure, lattice defects and the stress–strain parameters were examined using different models (Size–strain plot method (SPP) Williamson–Hall (W–H) and Halder–Wagner (H–W)), which showed a variation by changing the heating (aging) time (HT). It was found that crystal structure, lattice defects and the stress–strain parameters changed with changing HT. The obtained HR-TEM of the ZnO NS indicated good crystalline structure, spherical and uniform shape. The optical properties of the obtained ZnO NS as a function of HT were described using the spectroscopies: UV–Vis and photoluminescence (PL). The UV–Vis results exhibited a red shift for the absorption band edges, where the estimated optical energy gap (Eg) slightly decreased and shifted to the lower energy region with increasing of HT. The PL emission spectra of the ZnO NS decomposed into two sections ranged from visible to Near-Ultraviolet (NUV). The obtained optical properties are in full agreement with the variation of structural properties obtained using the different XRD models and HR-TEM results. The synthesized particles were used as photoanode in DSSCs sensitized by different organic dyes (Eosin B, Rhodamine B, and Eosin Y). A variation of the overall cell efficiency was observed by changing HT. the sensitizer Eosin Y showed the best efficiency over the other organic dyes with light to electric efficiency of 1%.

Structural, morphological and optical characterization of Ti-doped ZnO nanorod thin film synthesized by spray pyrolysis technique

Thin films of pure and Ti metal ion doped ZnO were grown on glass substrate by spray pyrolysis for various doping ratios keeping the temperature at 400 °C. Impact of Ti doping on morphological, optical and structural properties of ZnO was investigated. Structural confirmation of the thin-film was analyzed by using X-ray diffraction (XRD) studies and it concluded the successful growth of standard thin films of hexagonal wurtzite structure which was polycrystalline in nature. The morphological studies carried out using Scanning Electronic microscope (SEM), endorsed a uniform distribution of grain that are spherical in nature. Composition analysis by energy dispersive spectroscopy showed the presence of Ti, Zn and O in the films. Average grain size was estimated using Scherrer formula and obtained to be in the range of 35 to 50 nm. Atomic force microscopy was used to provide the surface roughness that had increased with the increase of Ti concentration. In the visible region, these films were found to be highly transparent and the average transmittance was obtained to be 85%. Photoluminescence spectral analysis showed a near band edge emission at 397 nm.

The effect of silver doped in zinc oxide nanorods on titanium dioxide seeded substrate synthesized by binary solution technique

Non-doped and Ag-doped ZnO nanorods were fabricated on TiO2 seed layer by using two methods (binary method), a spin-coating technique for the deposition of TiO2 seed layer and a solution-immersion method for the growth of ZnO nanorods. Varied quantities, 0.5 at%, 1.0 at%, 1.5 at%, 2.0 at% and 2.5 at%, of Ag-doped ZnO/TiO2 had an effect on the morphological, optical and structural properties of ZnO, and this was investigated by using FESEM, UV–vis and XRD. FESEM images revealed the morphology as nanorods and 1.5 at% of Ag dopant produced the smallest nanorod diameter. UV–vis and XRD results also indicate that 1.5 at% of Ag dopant showed the highest absorbance and highest intensity, which supports the FESEM results. Thus, 1.5 at% Ag dopant showed very good potential to produce a good optical property due to high crystallinity, small nanorod size with high absorption in the UV region compared to the other samples.

Substrate Temperature Effects on Optical and Structural Properties of ZnO:Al Films Deposited from Nanopowder Target Materials

Substrate Temperature Effects on Optical and Structural Properties of ZnO:Al Films Deposited from Nanopowder Target Materials

Experimental and theoretical study of visible light driven scandium (III) doped ZnO for antibacterial activity

Abstract ZnO was doped with Sc(III) ions to obtain a low-cost and environment-friendly antibacterial material with highly synergistic antimicrobial activity. The combination of experimental results and theoretical insights was used to describe the effect of Sc doping on the electronic and structural properties of ZnO. Sc(III)-doped ZnO materials with different Sc(III) contents were deposited on white carbon black (WCB) by a facile sol-gel method. The Sc(III) doped antibacterial materials were characterized by FESEM, EDX, HR-TEM, BET, XPS, XRD, ICP-OES, UV–visible spectroscopy, Fastsage and Materials Studio (MS). The antibacterial activities of Zn WCB and Zn–Sc WCB were determined by counting Escherichia coli (E. coli) and Staphylococcus aureus (S.aureus) colonies on bacterial culture plates. The results show that the specific surface area of Sc-doped Zn on WCB was increased by 31.9 m2/g compared to Zn WCB. The optimum doping ratio of Zn and Sc was determined in Zn0.9574Sc0.0426O cut from hexagonal wurtzite structure ZnO. Moreover, pure ZnO and Zn0.9574Sc0.0426O models were established by density functional theory (DFT). The experimental results and DFT calculations demonstrated that ZnO WCB possessed excellent antibacterial properties after doping with Sc. This improved antibacterial activity was due to the effects of Sc2O3 on the ZnO lattice, which resulted in the generation of excess reactive oxygen species (ROS).

Optical and structural properties of ZnO:Eu thin films grown by pulsed laser deposition

Eu doped ZnO thin films were deposited by pulsed laser deposition on fused silica substrate at room temperature and 300 °C in an oxygen ambient of pressure of 10 Pa. The films exhibited a wurtzite structure. The average transmittance exceeded 80% in the visible region confirming a good optical quality of the films. The characteristic emission of both Eu2+ and Eu3+ was observed when indirectly excited. The increase of substrate temperature to 300 °C led to higher crystallites size, lower efficiency of energy transfer from ZnO to Eu ions and lower resistivity of the film. XPS revealed the ratio of Eu divalent and trivalent states as 35%:65% and 27%:73% for sample deposited at room temperature and 300 °C, respectively. AFM showed higher RMS for the sample prepared at 300 °C.

Effect of Solvent Medium on Optical and Structural Properties of ZnO–SnO2 Nanocomposite

Effect of Solvent Medium on Optical and Structural Properties of ZnO–SnO₂ Nanocomposite

The efficiency of ZnO/platinum octaethylporphyrin (PtOEP) nanocomposite photoanode at dye-sensitized solar cells

In the present work, we have been studied the applications of ZnO/platinum octaethylporphyrin (PtOEP) nanocomposites as photoanodes for dye-sensitized solar cells (DSSC). The structural properties of ZnO:PtOEP nanocomposites were examined by X-ray diffraction and Raman spectroscopy analysis which confirm the hexagonal wurtzite ZnO structure. Also, the simultaneous existence of PtOEP and ZnO in XRD and Raman mode was confirmed the formation of nanocomposite. Scanning electron microscopy image of the surface morphology confirms the presence of PtOEP particle in the film. The variation in the weight ratios of ZnO:PtOEP is taken to optimize the performance of the DSSC. The photovoltaic and electrochemical impedance spectroscopy (EIS) data indicate that the optimum performance can be achieved at ZnO:PtOEP(1:0.009). Also, the (EIS) measurement of ZnO:PtOEP(1:0.009) photoanode shows displayed faster electron transport, significantly increased electron lifetime, and higher charge collection efficiency than those of pure ZnO.

Effect of the Cu plasma density on ZnO:Cu thin films grown by PLD

ZnO:Cu thin films were deposited on Si (100) substrates at room temperature by the simultaneous laser ablation of Zn and Cu targets. The plasma parameters (mean kinetic energy (Ek) and density (Np)) were calculated using the time of flight curves obtained from Langmuir planar probe measurements and used as control parameters for the deposition process. In order to change the Cu content incorporated into the films, Np-Cu was varied while keeping Ek-Cu constant. On the other hand, Zinc plasma parameters were both kept constant. The main purpose of this research was to study the effect of combining Zn and Cu plasmas on the optical and structural properties of ZnO:Cu films. Additionally, the effect of a hydrothermal annealing using deionized water as a heterogeneous medium was investigated. XRD results showed a growth in the (101) orientation for all samples. Crystallinity in samples is influenced by plasma density from Cu target (Np-Cu), containing Cu+1 and Cu+2 ions. XRD and PL suggest a Cu+1 incorporation in films grown at intermediate plasma density.

Synthesis and structural properties of ZnO doped nanoparticles prepared by hydrothermal method

ABSTRACTThe present study investigates the structural properties of pure and doped ZnO nanosized particles. The nanosized particles were synthesized by using hydrothermal process at room temperature. Nanoparticles have been characterized for its optical, structural properties using UV–VIS spectrophotometer and X-ray diffraction (XRD). XRD results show that the prepared samples have single phase and has hexagonal wurtzite structure. Further, the crystallite size of the ZnO nanoparticles have been determined using Scherrer, Williamson Hall method and size strain plot. The different chemical nature and different ionic radii are main effect, which shows different properties for the different dopant as compared to the host cation. Due to the different doping content, the crystallite size of nanoparticles found to be increased. The physical parameters such as strain-stress curve and energy values were calculated for all the reflected peaks of XRD data.

Simultaneous tuning of electric field intensity and structural properties of ZnO: Graphene nanostructures for FOSPR based nicotine sensor

We report theoretical and experimental realization of a SPR based fiber optic nicotine sensor having coatings of silver and graphene doped ZnO nanostructure onto the unclad core of the optical fiber. The volume fraction (f) of graphene in ZnO was optimized using simulation of electric field intensity. Four types of graphene doped ZnO nanostructures viz. nanocomposites, nanoflowers, nanotubes and nanofibers were prepared using optimized value of f. The morphology, photoluminescence (PL) spectra and UV–vis spectra of these nanostructures were studied. The peak PL intensity was found to be highest for ZnO: graphene nanofibers. The optimized value of f in ZnO: graphene nanofiber was reconfirmed using UV–vis spectroscopy. The experiments were performed on the fiber optic probe fabricated with Ag/ZnO: graphene layer and optimized parameters for in-situ detection of nicotine. The interaction of nicotine with ZnO: graphene nanostructures alters the dielectric function of ZnO: graphene nanostructure which is manifested in terms of shift in resonance wavelength. From the sensing signal, the performance parameters were measured including sensitivity, limit of detection (LOD), limit of quantification (LOQ), stability, repeatability and selectivity. The real sample prepared using cigarette tobacco leaves and analyzed using the fabricated sensor makes it suitable for practical applications. The achieved values of LOD and LOQ are found to be unrivalled in comparison to the reported ones. The sensor possesses additional advantages such as, immunity to electromagnetic interference, low cost, capability of online monitoring, remote sensing.

Focused ion beam surface treatments of single crystal zinc oxide for device fabrication

We investigated 30kVGa+ ions treatments on (0001) single crystal ZnO in order to assess the potentiality of ion beam based device fabrication on such material. A multi-technique approach combining atomic force microscopy, Raman and energy dispersive X-Ray spectroscopies, and transmission electron microscopy was used to study morphological and structural properties of ZnO upon varying the ion dose. At low doses a shallow defective layer develops showing an increasing defect density as the dose is increased. At higher dose a thinner defective layer with an amorphous layer on top is produced. The ion beam damaged layer on high resistivity ZnO shows enhanced conductivity. KOH based etching removed selectively the damaged ZnO and was found to dissolve rapidly the Ga-rich amorphous layer. The defective layer has an etch rate which depends on the ion dose, and even for prolonged etching processes it was not completely removed. However, conductivity measurements on ion beam fabricated pillars showed that the residual defects do not give a detectable electrical response. These findings indicate that electronic devices and micro-structures with pristine electrical properties of the ZnO crystal can be reliably fabricated by focused ion beam, provided the damaged surface layer is removed by proper etching procedures.

Biomorphic ZnO structures: Synthesis and optical properties

ABSTRACTBiomorphic ZnO structures with different morphologies were grown by a simple and green technique using various biotemplates. The well-defined chemical of the biotemplates can be exploited for control of size and shape of the formed ZnO structures. The growth mechanism of samples could involve the role of preformed nucleus and used biotemplates to provide suitable conditions for oriented growth of primary nanoparticles. Therefore, the effect of biotemplates on structural and optical properties, especially morphology of ZnO structures, was investigated in this study. Optical properties of ZnO structures including nanorods, microrods, nanosheets, and nanoparticles were studied by UV–Vis and photoluminescence spectroscopy techniques.

Effect of CuO loading on Structural Properties of ZnO

Effect of CuO loading on Structural Properties of ZnO

The effect of millisecond flash lamp annealing on electrical and structural properties of ZnO:Al/Si structures

The effect of millisecond flash lamp annealing (FLA) on aluminum doped ZnO (AZO) films and their interface with Si have been studied. The AZO films were deposited by magnetron sputtering on Si (100) substrates. The electrical and structural properties of the film and AZO/Si structures were characterized by current–voltage, capacitance–voltage, and deep level transient spectroscopy measurements, X-ray diffraction, and secondary ion mass spectrometry. The resistivity of the AZO film is reduced to a close to state-of-the-art value of 2 × 10−4 Ω cm after FLA for 3 ms with an average energy density of 29 J/cm2. In addition, most of the interfacial defects energy levels are simultaneously annealed out, except for one persisting shallow level, tentatively assigned to the vacancy-oxygen complex in Si, which was not affected by FLA. Subsequent to the FLA, the samples were treated in N2 or forming gas (FG) (N2/H2, 90/10%mole) ambient at 200–500 °C. The latter samples maintained the low resistivity achieved after the FLA, but not the former ones. The interfacial defect level persisting after the FLA is removed by the FG treatment, concurrently as another level emerges at ∼0.18 eV below the conduction band. The electrical data of the AZO films are discussed in term of point defects controlling the resistivity, and it is argued that the FLA promotes formation of electrically neutral clusters of Zink vacancies (VZn's) rather than passivating/compensating complexes between the Al donors and VZn's.