Doped ZnO Samples Research Articles

Investigating the dielectric and ferromagnetic behaviour of Ni and Co dual doped ZnO for diluted magnetic semiconductor

Herein, Ni/Co co-doped ZnO nanoparticles (NPs) were successfully prepared via chemical co-precipitation process. The structural, purity and crystallite size of as-prepared particles were confirmed by using x-ray diffraction (XRD). The results revealed the hexagonal wurtzite structure of ZnO without any impurity phase of as-prepared samples. The crystallite size decreased from 34.9 to 9.6 nm, whereas lattice strain reduced to 0.00086. The change in crystallite size, lattice parameters, strains and dislocation density further indicates the successful incorporation of dopants in ZnO host lattice. The dielectric properties, ac conductivity, and magnetic behaviour were steadily examined. The dielectric constant has been found to be 1070 with 5wt% at low frequency and become constant at higher frequency. It was revealed that dopant additions lead to attain high dielectric constant and low loss possibly attributed to interface polarization, and dipole polarization due to oxygen vacancy defects. M-H measurement observed that ferromagnetism at room temperature pure and doped ZnO samples. The ferromagnetic behaviour of pure ZnO NPs with Ms = 0.17 emu g−1, Mr = 0.11 emu g−1 and Hc = 67 which was increased to Ms = 0.85 emu g−1 and Mr = 0.65 emu/g for 5wt% Co. This improvement with increasing Co concentration indicates that oxygen defects may stabilize the ferromagnetic order. These interesting features encouraging to use this material for ultrahigh dielectric materials and spintronics.

Green mediated approach to investigate the optical, structural, photocatalytic, magnetic and dielectric properties of Cr3+ doped ZnO nanoparticles for energy applications

Herein, the influence of Cr3+ dopant on the structural, morphological, optical, photocatalytic, dielectric and magnetic properties of ZnO was investigated for various applications. Pure ZnO and Cr3+ doped ZnO nanoparticles were synthesised by green mediated approach. The synthesised nanoparticles examined by using XRD, SEM, EDX, FTIR, PL, UV–Vis spectroscopy, dielectric and magnetic analysis. XRD confirmed the wurtizte hexagonal structure of synthesised samples and also revealed that the Cr didn't alter the structure of host ZnO. The FTIR analysis revealed the presence of Cr ions in ZnO structures. Doping of Cr ions improved the optical absorbance of ZnO and the optical band gap showed the blue shift with increasing concentration of Cr. The synthesised Cr doped nanoparticles show the outstanding photocatalytic efficiency under solar irradiation against MG pollutant dye. The dielectric constant (ε) improves and dielectric loss (tan (δ)) reduces at lower frequencies with increasing content of Cr. The AC conductivity for doped nanoparticles showed the increasing trend, especially for 4.5 % Cr doped ZnO nanoparticles. The ferromagnetic behavior at room temperature of Cr doped ZnO nanoparticles confirmed by VSM. The obtained results from all investigations make the Cr doped ZnO samples a potential choice for various applications such as, spin based electronic devices and energy storage devices.

Mg doped ZnO Nanostructures: application as an environmental photo-catalyst

In this era, metal oxide nanoparticles with appliances in solar, catalysis, sensors, actuators, and many other fields, are highly sought-after because of their wide band gap. This study examines the Mg doped ZnO nanoparticles for the structural, electrical transportation and photo-catalytic behaviour. The XRD, FT-IR (Infrared Spectroscopy), PL (Photoluminescence), and Complex Impedance Spectroscopy were used to characterise the prepared sample. The wurtzite hexagonal structure in space group P63mc was shown by the XRD data. The analyzed crystallite sizes, planner distances, and cell volumes of Mg doped ZnO nanoparticles are 35.2 nm, 2.6122 Å, and 60.91 Å3, respectively. The aggregation in sample is visible in the micrographs. The PL spectra was traced at an excitation wavelength of 330 nm (λ) using a PL spectrometer. Using the FTIR approach, IR spectra with acmes about 520–640 cm-1 were traced, leading to Zn–O bond stretching. Using a photocatalytic reactor, the photocatalytic degradation of magnesium-doped ZnO nanoparticles was measured for two hours. For the Mg doped ZnO sample, the degradation efficiencies (ɳ%) is 67 percent.

The influence of Nd3+ doping on the structural, optical, magnetic, and dielectric characteristics of nanoscale hexagonal wurtzite type ZnO

Nd3+ doped ZnO nanoparticles (NPs) Zn1−xNdxO (x = 0, 0.01, 0.03, and 0.05) were successfully synthesized via simple co-precipitation method. To extract precise crystallite size and lattice strain from the X-Ray Diffraction (XRD) pattern, Halder-Wagner method was employed. High Resolution Transmission Electron Microscopy (HRTEM) analysis clearly substantiates the NPs formation.The band gap variation in the doped samples in comparison with the pristine sample is extracted from UV–Vis diffuse reflection spectroscopy. The decrease in Photo-luminance (PL) intensity is observed to be significant for enhanced photocatalytic applications. At room temperature (RT), all Nd3+doped ZnO samples exhibit a distinct hysteretic loop. The initial magnetization graph and M-T curve fitted by the modified Brillouin function and combination of spin wave and Curie-Weiss law respectively. The well-fittings indicate the co-existence of paramagnetic (PM) and ferromagnetic (FM) phases in the doped sample, and the quantitative contribution to each phase is also extracted. Significantly high dielectric constant and low ac conductivity at a low frequency region support the presence of large dipolar effect-induced frequency-dependent short-range conductivity in these pristine and Nd3+ doped ZnO samples.

Enhanced photocatalytic activity of Er doped ZnO nanospindles and nanorods for degradation of organic pollutants

Rare earth doping in ZnO is an efficient way to improve the photocatalytic performance. In the present work, Er doped ZnO nanospindles and nanorods were prepared through a simple cost effective wet chemical approach and were thoroughly characterized by FESEM, XRD, Raman spectroscopy, UV–vis-DRS, UV–vis absorption and PL spectroscopy. Nanospindle and nanorod-like morphologies of the fabricated samples were revealed by FESEM. XRD analyses revealed hexagonal wurtzite structure of Er doped ZnO nanostructures and confirmed Er doping into ZnO. PL studies showed increased defect concentration in ZnO nanostructures doped with Er ions. The photodegradation ability of nanostructures was investigated using cationic and anionic dyes and photodecomposition rate of 0.042 min−1 was achieved for MB decolorization using 0.5 % Er doped ZnO sample upon 32 min of solar light illumination. The probable photodecomposition mechanism supported by in-situ radical trapping experiments and repeatability test have also been discussed and results suggest that Er doped ZnO photocatalyst exhibit potential for use as commercial solar-active photocatalysts.

Synthesis and characterization of ZNO: CU and AG bimetallics nanoparticles by sol gel method

Different weight ratios of Cu-silver-doped and non-doped ZnO nanoparticles were created, By using XRD, FTIR, UV-visible spectroscopy, FESEM, and EDS the presence of nanoparticles in the sol-gel (ZnO) and (ZnO: Ag and Cu) techniques was confirmed, the JCPDS standard card for Zn (01-080-0074) validated the hexagonal ZnO structure by X-ray diffraction for (ZnO) and (ZnO:Ag and Cu). we calculated the average crystal size of all the produced samples, and we observe that the crystal size grows as the ratio of copper and silver doping rises. According to the FTIR data, O-H expansion is responsible for the expected distinctive absorption band in the vicinity of (3090-3665 cm). Because KBr quickly absorbs CO, it is possible that the peaks in the range (1550-1630 cm) are caused by the KBr utilized. These peaks are related to the stretching vibrations of C=O that are symmetric and asymmetric. The stretching vibration of the ZnO bond can be seen in the form of a prominent peak in the (350–780 cm) range. When Ag and Cu are entered to the doped ZnO samples, the peak strength declines, indicating the start of Ag and Cu clusters on the surface of ZnO nanoparticles. The bond position was shifted as a result of alteration in bond length brought about by the substitution of Ag+ ions at the ZnO lattice sites. According to the UV-VIS measurements, pure ZnO has a peak at 370 nm that becomes red at 569 nm. With increasing concentrations of Ag and Cu, the nanocomposites show high absorption in the visible region because the peaks shift monotonously to longer wavelengths and cause the energy gap value to decrease by 3, 2.958, 2.76, 2.74, 2.69, and 2.5 eV, respectively. According to the FESEM data from IMAGE J, the nanoparticles have a spherical or nearly spherical form. Zn, Ag, and Cu elements may be seen in the EDS data.

Insight into the role of Mg/B and Mg/Cu dual dopant on the properties of ZnO nanoparticles prepared by facile one-step combustion route for photocatalytic and antibacterial application

ZnO semiconductors are widely known to have benefits in photocatalytic and antibacterial applications. In this study, (Mg/B)–ZnO and (Mg/Cu)–ZnO were synthesized using the combustion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The XRD results confirmed a decrease in the crystal size and an increase in the crystallinity of the doped ZnO samples. SEM analysis confirmed the morphological changes in the structure from rod-shaped to spherical, and the particle size decreased in the doped ZnO samples. EDS analysis validated the nanoparticle composition of Zn, O, Mg, B, and Cu without impurities. Raman spectra confirmed the formation of defects due to the substitution of dopants in the ZnO lattice. All samples for FTIR analysis showed functional chemical group vibrations from Zn–O, C–H, and O–H stretching. The existence of dopant bonds with oxygen was also validated from this analysis. The change in band gap energy was observed from 3.13 to 3.10 eV in Mg/Cu–ZnO and 3.12 eV in Mg/B–ZnO sample due to the influence of the addition of dopant ions. The XPS spectra show the chemical composition of the nanoparticle samples and the oxidation numbers that correlate with the results of EDS and XRD analyses. A decrease in the emission intensity in the PL measurement was observed in the green emission region in the Mg/B–ZnO sample, which correlated with the decrease in electron recombination. The Photocatalytic application was performed by measuring its ability to degrade methyl violet dye under visible-light irradiation. The maximum deterioration after 120 min of irradiation was obtained for the Mg/Cu–ZnO, Mg/B–ZnO, and ZnO samples at 92.62 %, 92.20 %, and 80.89 %, respectively. Antibacterial activity increased against S. aureus bacteria in co-doped ZnO samples with inhibition zones of 12.15 mm, 8.15 mm, and 6.45 mm for Mg/B–ZnO, Mg/Cu–ZnO, and ZnO samples, respectively.

Negative temperature co-efficient of resistance behaviour of Cr doped ZnO nanoceramics

Here, High Energy Ball Milling (HEBM) is used to prepare Cr doped ZnO (Zn1-xCrxO, x = 0–0.04) nanoceramics and their electrical behaviour is studied in detail. The X-ray diffraction suggests a hexagonal wurtzite structure. The Rietveld refinement XRD pattern of the sample calcined at 900 °C suggests that up to 4 at% of Cr can be doped into the ZnO structure. After sintering, the growth in the particle size was observed for Cr doped ZnO samples. The complex impedance behaviour of samples suggests a decrease in resistance with temperature. This shows the Negative Temperature Coefficient of Resistance (NTCR) characteristic of the Cr doped ZnO sample in the studied temperature range (300–500 °C). At higher temperature, the electrical relaxation behaviour is of the non-Debye type as observed from the relaxation time distribution. The equivalent electrical circuit of ZnO and Cr doped ZnO ceramic samples are a parallel arrangement of bulk capacitance (Cb) and bulk resistance (Rb).

Cu doped ZnO nanoparticles: Correlations between tuneable optoelectronic, antioxidant and photocatalytic activities

Microstructural, optical and electronic properties of Cu doped ZnO nanoparticles with a general formula Zn1-xCuxO (x = 0.0, 0.1 and 0.2) prepared via wet chemical co-precipitation method were investigated thoroughly. Both the free radicals scavenging properties and photocatalytic activities of synthesized nanoparticles were explored. Formation of pure hexagonal wurtzite crystal structure of entire samples were identified by recorded x-ray diffraction patterns. For determining both the mean crystallite size and intrinsic microstrain of all the samples, several standard methods were utilized and a comparative study was introduced. Average size, morphology and shape regularity of synthesized samples were examined using HRTEM images. Optical direct band gap estimated from Tauc plots was noted to reduce with increasing Cu concentration in ZnO nanoparticles. Collected FTIR spectra at 300 K also validated the incorporation of Cu ions and their complete dissolution in the host ZnO crystal structure. It is also found that the hopping of electrons is the fundamental charge conduction process for all the samples in presence of ac electric field. FDTD simulation clearly predicts increase in electric field intensity with increased doping of Cu. There could be a plasmonic coupling between particles at the hotspot region that increases the electric field intensities. BET study revealed that the 10 % Cu doped ZnO sample has highest specific surface area which implies it contains more active sites for taking part in rapid photodegradation of toxic dyes compared to other samples. It was observed that the 10 % Cu doped ZnO nanoparticles were more efficient in degrading toxic dyes and the degradation pathway of all the samples obeyed first order rate kinetics model. Based on estimated bandgap of nanoparticles, a possible mechanism for the Rhodamine B (RhB) and Methylene blue (MB) dye degradation is suggested. All the prepared samples also exhibited notable antioxidant properties. Consequently, this study clearly shows that the Cu doped ZnO nanoparticles are the effective nanomaterial for photocatalytic and antioxidant applications.

Investigation on the impact of cobalt doping on optical, structural and magnetic properties of zinc oxide nanoparticles

In the current article, we investigated the impact of transition metal Co2+ doping in ZnO nanoparticles and its effect on their optical, structural, and magnetic properties. The synthesized nanoparticles have the generic formula Zn1-xCoxO (x = 0.00, 0.03, 0.06, and 0.09). Single-phase hexagonal crystal structure of the synthesized nanopowder was confirmed by x-ray diffractograms. Tauc plots were used to calculate the band gap of all the samples. Multiple emission peaks were observed from the photoluminescence studies. HRTEM was employed to study the particle morphology and the size distribution. X-ray photoelectron (XPS) spectroscopy was performed to investigate the chemical composition of samples. Magnetic measurements were carried out to study the magnetic behaviour of pure and doped ZnO samples. Ferromagnetic behaviour became more prominent with the addition of Co doping, as observed by room temperature M-H plots.

Synthesis of Al‐doped and Fe–doped ZnO nanoparticles as UV filters in sunscreens

AbstractIn this work, Al‐doped ZnO and Fe‐doped ZnO nanoparticles have been synthesized through the coprecipitation‐annealing method to create new and safer UV filters for sunscreen. The effects of metal doping on phase composition, crystal structure, surface morphology, specific surface area, and elemental composition were characterized by X‐ray diffraction, Raman spectroscopy, field emission electron scanning microscopy, nitrogen adsorption‐desorption experiments and energy‐dispersive X‐ray spectroscopy, respectively. The optical properties and photocatalytic activity of prepared powders were studied through UV‐visible diffuse reflectance spectroscopy and photocatalytic degradation of methylene blue under UV radiation. According to the experimental results, Al or Fe‐doped ZnO nanoparticles showed better UV absorption but significantly lower photocatalytic activity than the undoped ZnO sample, which enables the metal doped ZnO samples to become more effective and safer UV filter in sunscreen. The decline of photocatalytic activity can be attributed to the bulk defects caused by the insertion of Al3+ or Fe3+ ions in ZnO lattice. In particular, the sunscreen formulations using the metal doped ZnO nanoparticles display high SPF values and diverse colors changing from ivory to yellow‐brown, preventing leaving white cast on the skin, which is very suitable as sunscreen for people of color.

Effect of Bi doping on the opto-electronic properties of ZnO nanoparticles for photodetector applications

Bi (0, 1, 3 and 5 wt%) doped ZnO nanopowders were generated in this study using a simple and inexpensive wet chemical method. X-ray diffraction, Fourier-transform infrared spectroscopy, Scanning electron microscopy, photoluminescence spectroscopy, UV–Vis-DRS, studies are used to evaluate the effect of dopants in ZnO sample. Crystallite size and grain size of the samples were reduced and enhanced the surface to volume ratio due to Bi doping. Oxygen vacancies and shrinkage of bandgap plays a significant role in enhancement of photosensing property. Bi doped ZnO nanopowders had better photosensing activity than pristine ZnO nanopowders. Also, the doped metal ions improved the photosensing efficiency by increasing electromagnetic wave absorption and inhibiting the recombination rates of charge carriers resulting raise of hole-electron pair production. The significant photosensing parameters responsivity (R), detectivity (D*) and external quantum efficiency (EQE) of the 3 % of Bi doped ZnO sample exhibited maximum values such as 0.163 AW−1, 1.26 × 1010 Jones and 53% respectively. The findings of this present study show that the3 % Bi doped ZnO can be an excellent photosensing material.

Preparation of tungsten-doped zinc oxide thin films by co-sputtering for micro-gas sensing devices

Synthesis of a good nanostructure is a vital part in regards to achieving proper gas sensing characteristics. In this study, Tungsten (W) doped ZnO nanostructure is synthesized on micro electro mechanical systems (MEMS) device by co-sputtering process. Appropriate doping concentration to the sensing material is crucial for sensing properties, therefore, 5 different doping concentrations ranging from 0% W to 4% W to the ZnO structure are developed. The structural properties of all the W doped ZnO samples were characterized by Scanning electron microscope (SEM), X-Ray diffraction (XRD) analysis and Energy-dispersive X-ray spectroscopy (EDS) analysis. Sensing properties were calculated with different concentrations of H2 gas ranging from 20 ppm to 100 ppm. All of the W doped ZnO sensors were tested for H2 gas at working temperatures varying from 100 °C to 300 °C to detect the optimal doping concentration and optimal working temperature. At 150 °C, 3% W doped ZnO revealed 67% gas sensing response for 100 ppm H2 gas. Selectivity test with 5 different gases displayed that W doped ZnO sensor has good selectivity over H2 gas at 150 °C.

Chromium-doped ZnO nanoparticles synthesized via auto-combustion: Evaluation of concentration-dependent structural, band gap-narrowing effect, luminescence properties and photocatalytic activity

Herein we report the effect of the Cr3+ content on the distinctive features of the first-ever auto-combustion-synthesis-produced Cr3+ doped ZnO nanoparticles utilizing leucine as the fuel. To assess the impact of fuel and Cr3+ content on the structural, optical, and luminescence characteristics, as-synthesized powders were systematically examined using powder XRD, UV–Visible, and Photoluminescence spectroscopy. Structural studies show that the exothermicity of the redox mixture containing oxidizer and fuel combination leads to the development of polycrystalline, single-phase, and nanosized particles. XRD analysis shows that, reduced crystallite size with Cr3+ content. In contrast, other characteristics like lattice parameters, unit cell volume, strain, and dislocation density, were shown to increase linearly with Cr3+ concentration up to 7 mol%. Additionally, it is seen that the predicted Urbach energy values rise as Cr3+ is added to the ZnO host matrix, indicating that the substitution of Cr3+ for Zn in the host ZnO lattice has increased structural disorder. In contrast to the other samples, the 5 mol% Cr3+ doped ZnO sample exhibits the emission near the white region according to the PL emission measurements. Furthermore, the photocatalytic activity of the as-prepared Cr3+ doped ZnO NPs was examined. It was found that the as-prepared samples exhibit outstanding photocatalytic activity in the visible wavelength region against Malachite Green (MG) dye. Among all, 9 mol% Cr3+ doped ZnO has shown the maximum 95.4% degradation against MG dye. All the investigated results conclude that the produced Cr3+ doped ZnO nanoparticles could be exploited in a variety of upcoming optoelectronic and photocatalytic applications.

Effective role of vibrational annealing in enhancing room temperature physical properties of Co doped ZnO nanoparticles by using novel TVA technique

Well-annealed nanocrystalline semiconductor materials in pellet or thin film form, composed of small grains with a high surface-to-volume ratio, are considered as promising candidates for multiple device applications. However, no such method is available yet that can control the grain size of such samples during heat treatment. In this present work, a novel thermo-vibrational annealing (TVA) setup for processing nanocrystalline materials was designed and fabricated in-house. Here both thermal and mechanical vibrational energy were simultaneously applied to the sample during annealing, followed by vibrational dry quenching in the presence of an inert gas environment. Co-doped ZnO pellets were synthesized by chemical route pyrophoric method followed by annealing at 800 °C for 4 h using this set up. For comparison, one pellet was annealed with vibration with calibrated vibration at a speed of 360 rpm, and another pellet was annealed without vibration. X-ray diffraction (XRD), Raman and Fourier transform Infrared (FTIR) spectroscopic studies showed the formation of a single crystalline phase with hexagonal wurtzite structure of both the samples and the proper incorporation of Co2+ ions into the ZnO matrix without any impurity phases, which was also confirmed by energy dispersive X-ray (EDX) spectroscopy studies. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) studies confirmed the decrease in average grain and particle size of the sample when processed with the TVA setup. Ultraviolet–Visible spectra showed that the bandgap energy of the Co-doped ZnO sample varies inversely with particle size. Hall-effect measurements demonstrated the semiconducting nature of both samples with n-type charge carriers. The presence of Co2+ ions in the wurtzite ZnO lattice was confirmed by X-ray photoelectron spectroscopy (XPS). The magnetic properties were studied using a SQUID magnetometer, which confirmed that a Co doped ZnO sample annealed with the TVA technique exhibit better room temperature ferromagnetism properties compared to sample annealed without vibration. Based on these studies, it was believed that the sample annealed by mechanical vibrational energy with vibrational dry quenching has a great influence on several physical properties of any material and hence Co doped ZnO sample processed with this TVA technique can be used as a promising candidate for multiple sensor and magnetic storage devices.

Effect of Ni doping on structural, optical and gas sensing properties of ZnO films for the development of acetone sensor devices

The development of sensor materials for environmental air surveillance is very challenging. In order to meet the demand, the present study corelates the effect of nickel doping on structural, optical, morphological and gas sensing ability of zinc oxide thin films. The films were deposited on the glass substrates using spray pyrolysis technique. The crystalline character and morphological analysis of the films were characterized by X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). The hexagonal wurtzite structure of polycrystalline nature is observed from the XRD patterns. The preferred orientation is (101), however doping has significantly triggered (002) orientation. Systematic decrement in the lattice parameters and bond length have been observed which led to structural distortions as result of mismatch in ionic radii of dopant and host materials. FESEM analysis reveals that thin film samples exhibit nanoflake morphology. A well-defined morphology is observed with Ni doping. The compositional analysis (Energy dispersive X-ray spectroscopy) shows that the Ni content was increased with doping which confirm the successful Ni doping. Optical analysis of the samples was performed using UV–Vis spectroscopical analysis. Transmission spectra indicated the highest transmission value in the case of undoped ZnO samples (More than 80%). Gradually decreasing band gap values of ZnO films were observed with Ni doping. The sensor response was investigated for undoped and Ni doped ZnO samples at room temperature in the absence and presence of acetone with 50 ppm concentration. Optimum response (∼78%) is obtained for Ni doped ZnO (2% Ni) samples with response time of 33s. Spray synthesized 2% Ni doped ZnO thin film samples show promising approach to achieve high response at ambient temperature.

Optical, structural properties and photocatalytic potential of Nd-ZnO nanoparticles synthesized by hydrothermal method

The structural, optical, and photocatalytic properties of hydrothermally produced ZnO and Nd-ZnO nanostructures were studied. Doped and un-doped nanomaterials properties examine by (XRD) X-ray diffraction, (FESEM) Field Emission Scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and (DRS) UV–vis diffuse reflectance spectroscopy. XRD results show that ZnO crystalline size increases from 21.13 nm to 29.59 nm with Nd doping. DRS study indicates that energy band gap of doped ZnO sample was 3.19 eV while in case of ZnO sample 3.26 eV. The hexagonal rod shape morphology of doped ZnO was established by FESEM analyses. The photocatalytic activities of the produced nanomaterials were determined by Congo red dye photodegradation under UV and Solar light. In UV and Solar light, the photocatalytic activity of Nd-doped incorporated ZnO for CR degradation was 98.5 % and 91 %, respectively.

Tuning Optical and Electrical Properties of Ultra-Fast Prepared Nanoflower Mg:ZnO Films by MWCNTs Coating

Mg doped ZnO films were coated multi-walled carbon nanotubes (MWCNTs) via fast chemical bath onto ZnO seed layers. XRD analysis showed preferential orientation shift from high-energy (002) peak to low-energy (101) peak with MWCNTs coating. Average crystalline size of Mg doped ZnO samples are 15 nm. diameter and 50% percent reduction has been observed with MWCNTs coating. SEM images reveals the presence of high accumulative nanoflower forms on Mg:ZnO surfaces and homogenous net-shaped coating has been achieved by MWCNTs inclusion so active surface area may increase. No major difference of optical absorption edge is detected in both films however MWCNTs coating cause an increase direct band gap. Due to Burstein-Moss effect, Mg:ZnO and Mg:ZnO/MWCNTs films with using Tauc plot calculated band gap values are 3.04 eV and 3.34 eV, respectively. From FTIR spectra, no obvious change is not detected the functional groups of the samples. Electrical studies show that MWCNTs decrease the resistance and the resistance of films at room temperature were calculated 29.85 and 8.53 k for Mg:ZnO and Mg:ZnO/MWCNTs films , respectively.

The effect of magnesium doping concentration on the structural and optical properties of zinc oxide nanoparticles

In this study, the optical and structural properties of Magnesium doped Zinc Oxide (Zn1-xMgxO) nanoparticles (x = 1%, 3%, and 5%) were examined. The synthesis was carried out at 300 oC by using a simple co-precipitation method. The structural samples were used to characterize the synthesized nanoparticles by using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Energy Dispersive X-Ray spectroscopy (EDX) was used to determine the chemical composition of the samples. Furthermore, UV-Vis spectroscopy was conducted to study our samples’ optical characteristics. As per XRD analysis, both pure and Mg doped ZnO samples possess wurtzite structure. The particle size was revealed to decrease significantly with Mg concentration, from 36 nm for pure sample to 23.87 nm with 5% Mg. In comparison to ZnO, the XRD pattern of Mg-doped ZnO shows a peak shift towards lower 2θ values. As a result of deformation of crystal structure caused by integrated Mg+2 ions onto Zn+2 sites. SEM images of synthesized samples reveal that the nanoparticles possess sheet, spherical and rod like morphologies for different values of x. The EDX analysis verifies the purity of samples within the detection limits. According to optical absorption spectra obtained from UV-Visible spectroscopy in the 200nm to 1000nm range affirmed that as Mg concentration increased, the band gap increased from 3.37 eV for pure sample to 3.74 eV with 5% Mg. The UV-Visible spectra of pure ZnO and Mg-doped ZnO samples also exhibit distinct peaks in the UV region at 335 nm, 311 nm, 310.6 nm, and 310 nm. Across the spectra of pure and Mg-doped ZnO samples, the UV peak is attributed to free exciton transitions, whereas, in the spectra of Mg-doped ZnO UV absorbance peak in the visible region is attributed to the radiative transitions of electrons captured at oxygen vacant sites with holes trapped at singly ionized oxygen vacancies.

Optical, structural and morphological properties of ZnO and Fe+3 doped ZnO-NPs prepared by Foeniculum vulgare extract as capping agent for optoelectronic applications

The green method was utilized to synthesize pure,0.02Fe and 0.05Fe doped ZnO NPs at room temperature. The capping agent (extract of Fennel leaves) was handled throughout the preparation process. The prepared samples have been characterized by SEM, EDX, FTIR, UV–vis and XRD. XRD showed that all the prepared samples have a hexagonal structure with average crystallite size is in the range 27–24.65 nm. SEM appeared the difference in the morphology of pure and 0.05Fe doped ZnO NPs. EDX spectra confirmed the presence of O, Zn in all samples and Fe in 0.05Fe doped ZnO sample. The FT-IR spectrum confirmed the existence of Fennel leaves extract as a capping agent. The UV–visible showed the change in the band gap between the pure sample and doped samples, which were in the range 3.87–4.22 eV. This blue shift is attributed to the quantum confinement effect. The antibacterial analysis displayed that 0.02 and 0.05Fe doped ZnO NPs have a higher activity as compared to pure ZnO NPs. The results also showed that there were more positive antibacterial effects on Gram-positive bacteria than on Gram-negative bacteria. This materials with great optical, structural and antibacterial properties can be used for antibiotics development and can be widely used in medical applications and optoelectronic devices.