Hexagonal Wurtzite Structure Of ZnO Research Articles

Erbium-doped ZnO nanoparticles for anode materials: A comparative study using anthocyanin and curcumin dyes in DSSC

Nanomaterials doped with rare earth ions have attracted increasing interest in the renewable energy harvesting field. Erbium-doped ZnO nanoparticles were prepared by the solution polymerization method. The hexagonal wurtzite structure of ZnO was preserved, according to X-ray diffraction (XRD) studies, and the average crystallite size is less than 20 nm. The UV–Vis spectroscopy revealed that the optical band gap was 3.1 eV, with peaks associated with erbium-specific electronic transitions appearing when the doping concentration was raised (Er). Anthocyanin and curcumin dyes were employed to build dye-sensitized solar cells devices (DSSCs) employing nanoparticles as photoanodes. When compared to undoped ZnO, Er-doped ZnO at 1.25 at. percent improves power conversion efficiency (PCE) by 200% for anthocyanin dye and 10% for curcumin dye.

Green synthesis of RGO-ZnO mediated Ocimum basilicum leaves extract nanocomposite for antioxidant, antibacterial, antidiabetic and photocatalytic activity

Green chemistry of nanomaterials from synthesis to diverse biomedical applications is a discussion of town in the current scientific scenario. In this work, Ocimum basilicum leaves extract was utilized as the reducing agent in the synthesis of ZnO nanoparticles. Green synthesized ZnO NPs mediated via Ocimum basilicum extract were decorated on the reduced graphene oxide (RGO) sheet by the simple one-step method. The prepared green synthesized RGO-ZnO nanocomposites (NCs) were characterized via the X-ray diffractometer. The average crystallite size of ZnO was 25 nm which confirmed the wurtzite hexagonal structure of ZnO. The scanning Electron Microscopy technique confirmed the spherical morphology of particle size of 31 nm. Further, Fourier Transform Infrared Spectroscopy confirms the Zn-O bond stretching in the RGO-ZnO NCs. Antioxidant activity of the green synthesized Ocimum basilicum ZnO NPs and RGO-ZnO NCs were performed by DPPH scavenging activities and found the dose-dependent. RGO-ZnO effectively inhibited the α-amylase and α-glucosidase for in vitro antidiabetic activities. Moreover, RGO-ZnO NCs showed the antibacterial potential with increasing concentration against the gram-positive (Cocci) and gram-negative (E. coli) bacterial strains. In Photocatalytic activity, the ZnO NPs and RGO-ZnO NCs were utilized as the catalyst and degraded the Rh-B dye 91.4% and 96.7% under UV–visible light. Overall, RGO-ZnO NCs showed better results in antibacterial, antidiabetic activity as well as photocatalytic activity against the pure ZnO NPs. Hence, RGO-ZnO nanocomposites have demonstrated the opportunity to be an entrancing material for photocatalysis and biological studies.

Defect emission photoluminescence peak tuning by encapsulation of Au-NPs on ZnO mesoporous nanosponges

We synthesized Au nanoparticles (Au-NPs) encapsulated zinc oxide (ZnO:Au) nanosponges by the fraternization of ZnO nanoflowers with HCl (0–30 mM) concentrated colloidal Au-NPs at room temperature. The crystallite size (D) of mesoporous ZnO:Au decreased from 44 nm to 22 nm and the strain (τ) increased from 2.5 × 10−3 to 4.7 × 10−3 as the HCl concentration of colloidal Au-NPs increased from 0 mM to 30 mM. For elemental composition of ZnO:Au nanosponges, the STM-mapping confirmed the Au-NPs encapsulation on nanostructured ZnO. The bandgap, Eg, and the Urbach energy, Eu, of ZnO:Au decreased from 3.26 to 2.96 eV, and from 0.335 to 0.318 eV, as the colloidal Au-NPs increased from 0 mM to 30 mM, respectively. The structural and microstructure analysis showed the sponge like morphology along with wurtzite hexagonal structure of ZnO, which tuned the PL emission for the sensor selectivity. The visible emission of ZnO:Au nanosponges was greatly tuned from 600 nm to 500 nm with respect to the HCl diluted colloidal Au-NPs. The excellent photoluminescence (PL) performance of nanostructured ZnO:Au was attributed to the surface-plasmon-mediated sequential transfer of defect energy from ZnO to Au and electron transfer from excited Au to ZnO.

Structural and optical behavior of gallium and cobalt co-doped ZnO thin films fabricated by a sol-gel spin coating technique

In this study, the ZnO thin films with varying Ga/Co co-doping concentrations were produced on the quartz substrates by spin-coating technique. The structural and optical behavior of the films were analyzed by X-ray diffraction (XRD) and UV–Vis spectroscopy, respectively. XRD results reveal that all the films possess a hexagonal wurtzite structure of ZnO and have crystallite sizes in the range 8–24 nm. The prominent peaks (relative intensity greater than 10%) observed in the XRD profiles correspond to (100), (002), (101) and (103) planes, whereas the most preferred orientation of crystal growth in all the films is (002) plane. A small variation in the lattice constant values has been found owing to the inclusion of dopants and co-dopants in the ZnO lattice, as well as defects created in the crystal lattice at the time of film growth. Compared to the undoped ZnO film, the optical transmittance improves beyond the 430 nm wavelength upon 1 at% Ga doping, while in (1 at% Ga + 1 at% Co) and (3 at% Ga + 1 at% Co) co-doped films, it improves beyond the 600 nm wavelength. The UV–Vis spectroscopy results show the optical band gap value of 3.28 eV for the undoped ZnO film, which changes by a small amount in the doped and co-doped films.

PVDF@ZnO membrane for its potential application in oil/water separation

A facile synthesis of PVDF@ZnO membrane by cost-effective phase inversion method is reported. The samples are characterized by XRD, FTIR, FESEM and contact angle meter. XRD confirms the poly-crystalline nature of PVDF and the hexagonal wurtzite structure of ZnO. Contact angle studies show the membranes are hydrophobic-oleophilic in nature. An oil/water separation study shows that the membrane could effectively separate 96% of oily wastewater. The membranes can significantly degrade methylene blue under UV light. Such a dual-functional membrane that can separate oily wastewater and photocatalytically degrade organic contaminants in an aqueous environment might be a promising choice for wastewater treatment.

Modification in the physical properties of nanocrystalline ZnO thin films by Sn/Ni co-doping for transparent conductive oxide applications

In this paper, the modification in the physical properties of spin-coated ZnO thin films upon Sn/Ni co-doping has been presented. All the films possess the hexagonal wurtzite structure of ZnO with varying surface morphologies. Among all the films, the optical transmittance beyond 550 nm wavelength is maximum for the 1 at% Ni-doped ZnO (1NZO) and (1 at% Sn + 1 at% Ni) co-doped ZnO (1T1NZO) films. The optical band gap for the pristine ZnO film is 3.26 eV, which decreases upon doping and co-doping. The PL spectra of the films exhibit the UV emission corresponding to excitonic transitions and the blue and green emissions related to native defects in the ZnO structure. The room-temperature electrical conductivity is found maximum in the 1T1NZO film. The existence of 1T1NZO film with improved optical transmittance and high electrical conductivity supports its use in transparent conductive oxide applications.

Fabrication and characterization of sputtered Mg and F co-doped ZnO thin films with different substrate temperature for silicon thin-film solar cell applications

Transparent conducting oxide thin films have been extensively studied for various optoelectronic devices. In this paper, we investigated the influence of substrate temperature on structure, morphology, electrical and optical properties of Mg and F co-doped ZnO (MFZO) thin films. The MFZO films were deposited on glass substrates by radio frequency magnetron sputtering at a temperature ranging from room temperature to 200 °C. Experimental results indicate that small amounts of Mg (3 at%) and F (6 at%) co-doping does not change the (002) oriented hexagonal wurtzite structure of ZnO, but it can improve the crystallinity and optoelectronic properties by increasing the substrate temperature. For all MFZO films, the average transmittance in the visible region exceeds 91%. As the substrate temperature rises to 200 °C, the electrical resistivity of the film drops to 1.18 × 10−3 Ω cm. The high figure of merit (FOM) of the film deposited at 200 °C, 1.36 × 10−2 Ω−1 or 2.96 × 104 Ω−1 cm−1, makes it a transparent conductor of choice for photovoltaic applications. By etching with a dilute HCl solution, the surface morphology of the as-deposited MFZO film was modified to a crater-like texture, resulting in a significant increase in the average haze in the visible region from 4.5% to 52.3%. By employing the developed high-FOM and high-haze MFZO film as the front electrode of a-Si:H thin-film solar cells, a 30% increase in conversion efficiency was achieved under AM 1.5 G illumination.

Effect of low energy Ag+ ION implantation ON ZnO nanorods for enhanced visible light absorption- structural and optical analysis

Nanostructured one-dimensional ZnO nanorods (NRs) were grown on seeded borosilicate glass substrates through chemical bath deposition. The synthesised ZnO NRs were implanted with Ag + ions at low energy of 50 keV and varying fluences of 1 × 1015, 2 × 1015, 3 × 1015, 1 × 1016, and 3 × 1016 ions/cm2. The influence of injected Ag + ions was investigated on the structural and optical properties of ZnO NRs. A variation of X-ray diffraction (XRD) extracted and calculated microstructural parameters confirmed the presence of Ag+ ions on the grown ZnO NRs. XRD and Raman analysis revealed that the hexagonal wurtzite structure of ZnO was maintained, even at elevated fluences of Ag+ ions. Peak shifting to higher angles and lattice expansion were observed and attributed to substitutional doping. A red shift was observed in the absorbance spectra of Ag+ implanted ZnO NRs, suggesting a possibility of modification of the electronic structure which was confirmed through a calculation of the optical band gap and the refractive index. The energy band gap of Ag+ ion implanted ZnO NRs decreased with increase in the Ag+ ion fluence, whereas an increase was found for the calculated refractive index. The ZnO NRs implanted with 3 × 1016 ions/cm2 depicted different behaviour for structural and optical analysis, indicating a possibility of saturation of point defects and formation of different type of defects at fluences above 1 × 1016 ions/cm2. Corroboration of the structural and optical parameters demonstrate that low energy Ag + ion implantation can provide an effective and efficient approach to modify the structural and optoelectronic properties of ZnO for visible light driven photocatalytic applications.

Fabrication and characterization of ZnO/Zn2TiO4/ZnAl2O4 composite films by using magnetron sputtering with ceramic targets

Transparent conducting oxides (TCO), including ZnO/Zn2TiO4/ZnAl2O4 composite films, are of considerable importance in optoelectronic applications. We fabricated composite film assisted with DC magnetron sputtering using ceramic target material (ZnO, TiO2, and Al2O3 powders mixture). The influence of processing gases composition (0–50% O2–Ar) on film characteristics, including structural, optical, and electronic properties, is assessed. All films contain hexagonal wurtzite ZnO structure and ZnAl2O4, Zn2TiO4 spinel phases, with (002), (100), and (101) as dominant orientation by increasing oxygen contents. The transmittance of deposited films is above 81% (except for 50% oxygen), and the bandgap lies between 3.73 and 3.28 eV (reduced by oxygen addition). The carrier concentration and mobility increase with oxygen addition up to 25%, and resistivity decreases by increasing oxygen contents. This study shows that using ceramic targets, the compound film with variable composition, structural and optoelectronic properties can be obtained by altering the gases admixture.

Experimental investigation of performance tailoring of the multifunctional sensor using transition metal (Fe) doped ZnO nanorods synthesized via a facile solution-based method

A systematic interpretation of the undoped and Fe doped ZnO based multifunctional sensor developed employing economic and facile low-temperature hydrothermal method is reported. The tailoring of the performance improvement of the sensor was deliberately carried out using varied concentration (1, 3 and 5 Wt%) of Fe dopant in ZnO nanorods. The structural and morphological analysis reveal the undisturbed ZnO hexagonal wurtzite structure formation and 1D morphology grown even when the dopant is added. The optical property study evidences a decreased bandgap (3.10 eV) and decreased defects of 5 Wt% of Fe dopant in ZnO nanorods based sensor compared to the undoped one. The electrical process transpiring in the tailored multifunctional sensor is investigated using photoconductivity and impedance analysis elucidates proper construction of p–n junction between the piezoelectric n-type active layer (undoped and Fe doped ZnO nanorods) and p-type PEDOT:PSS ((poly(3,4-ethylene dioxythiophene) polystyrene sulfonate)) and reduced internal resistance of 5 Wt% of Fe dopant in ZnO nanorods based sensor (131.97 Ω) respectively. The investigation on the experimental piezoelectric acceleration and gas sensing validation and the performance measurement were interpreted using test systems. A revamped output voltage of 3.71 V for 1 g input acceleration and a comprehensive sensitivity of 7.17 V g−1 was achieved for the 5 Wt% of Fe dopant in ZnO nanorods based sensor sensor. Similarly, an upgraded sensitivity of 2.04 and 6.75 for 5 Wt% of Fe dopant in ZnO nanorods based sensor was obtained when exposed to 10 ppm of target gases namely CO and CH4 respectively at room temperature. Appending to this, acceptable stability of the sensor for both the sensing (acceleration and gas) was also attained manifesting its prospective application in multifunctional based systems like sewage systems.

Combustion synthesis and characterization of visible-light-driven Tm-doped ZnO nanoparticles used for photodegradation of methylene blue

Tm-doped ZnO nanoparticles were synthesized by a tartaric acid-assisted combustion method and followed by calcination at 600 oC for 2 h. Phase and morphology of assynthesized ZnO with and without Tm dopant were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The analytical results certified that Tm3+ ions were incorporated in hexagonal wurtzite ZnO structure. The particle size of ZnO was decreased with increasing in the weight content of Tm3+ dopant because the grain boundary growth of ZnO was hindered by Tm3+ dopant. The particle sizes of ZnO, 1% Tm-doped ZnO, 3% Tm-doped ZnO and 5% Tm-doped ZnO nanoparticles are 72.09 ± 17.37 nm, 32.77 ± 11.08 nm, 23.08 ± 4.61 nm and 25.27 ± 6.03 nm, respectively. The photocatalytic activity of as-synthesized ZnO with and without Tm dopant was evaluated through the degradation of methylene blue (MB) under visible light irradiation. In this research, 3% Tm-doped ZnO nanoparticles have the highest photocatalytic activity of 97.75% under visible light irradiation within 100 min. Active spices used for degradation of MB photocatalyzed by 3% Tm-doped ZnO nanoparticles were also investigated.

Mass fabrication of 2D nanostructure (ZnO) in chemical growth solution using tip induced lithography

ABSTRACT The present article reports an accelerated growth technique for fabrication of 2D assembly of ZnO nanostructure and investigated the impact of concentration variance on their grown morphology. The combination of zinc nitrate hexahydrate [Zn (NO3)2 · 6H2O] and hexamethylenetetramine (HMTA) is employed as growth solution having pH value of 6.0. The assembly of 2D nanostructures grown on microtip is accelerated by introducing the ultrafine discharge in the chemical growth solution. The synthesis, deposition, and growth time were limited to 20 seconds only. After deposition and growth, annealing heat treatment was applied at 95°C for 45 minutes to eliminate any impurities or crystal defects. The structural/morphological characterization through FESEM confirms that the fabricated nanostructure is of 2D nanosheet-like at lower molar concentration (0.10 M). Nevertheless, at higher concentration (0.20 M), the grown morphology changes to marigold flower-like structure with porousness in its crystal structure. The chemical characterization through EDX confirms the dominance of the ZnO in the fabricated nanostructure. The XRD results confirm the phase pure hexagonal wurtzite structure of ZnO with an average crystalline thickness of ≈27 nm. The availability of functional group and molecular fingerprint corresponds to ZnO stretching is identified by FTIR while elemental composition and their chemical states were analyzed by XPS.

An insight of physical and antibacterial properties of Au-doped ZnO dip coated thin films

Undoped and Au-doped ZnO thin films were dip coated on crown glass substrates by sol-gel process technique. The role of Au (1–5 at. wt.%) on structural, magnetic, morphological, dielectric, antibacterial and optical properties of the ZnO films were studied. XRD results depict that all films have a hexagonal wurtzite structure of ZnO and are a-axis oriented. The crystallite size thin films are decreased with an increase in Au doping percentage. Optical properties also confirmed that the s crystallinity degraded with the increase in Au percentage. UV–VIS–NIR optical spectra show that the increase in Au doping into ZnO lattice promotes their transparency. Surface morphology and surface roughness are modified by the Au doping concentration. Magnetic measurement exhibited room temperature ferromagnetic ordering in undoped and Au doped ZnO thin films. The enhancement in saturation magnetization with increase in Au doping is due to creation of defects in ZnO lattice by Au doping due to oxygen vacancies and structural inhomogeneity which leads to development of bound magnetic polarons. Variation in AC conductivity with change in Au dopant percentage is studied using Jonscher's power law which is linked with barrier-hopping mechanism. Au doped ZnO is effective against gram positive and gram-negative bacteria. These have antimicrobial applications in biomedicine and environmental shield. Au doped ZnO thin films are beneficial in spin LEDs and switchable diodes. The Au doped ZnO photocatalyst can efficiently degrade methylene blue dye; hence, it can be used for the treatment of wastewater contamination.

Hierarchical ZnO nanostructure flowers loaded with AgI nanoparticles for photodegradation of methylene blue under UV visible radiation

Hierarchical ZnO spherical flowers loaded with different weight contents of AgI nanoparticles were synthesized by deposition-precipitation method at room temperature and tested for photodegradation of methylene blue (MB) under UV visible light irradiation. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) connected with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). XRD patterns and SEM images of ZnO and AgI/ZnO hierarchical spherical flowers present pure phase of hexagonal wurtzite ZnO structure flowers and hexagonal wurtzite ZnO flowers supported with cubic AgI nanoparticles with size range of 80–90 nm on top. The photodegradation of MB was increased with increasing in the weight content of the loaded AgI nanoparticles on the surface of ZnO flowers. The 10% AgI/ZnO nanocomposites have the highest photocatalytic efficiency in degrading MB by h+ and ●OH as the main active species under visible light irradiation within 60 min.

Preparation of Fe2O3-ZnO Nanocomposites: Structure and Optical Properties

Background: The synthesis of Fe2O3/ZnO nanocomposites has gained wide acceptance in recent years due to its magnetic, photoluminescence and catalytic properties, and as an active element in gas sensors. This type of composite particle has potential biological and biomedical applications such as the detection of cancer cells, bacteria and viruses, and for magnetic separation. Objective: In the present study, first we synthesized the Fe2O3/ZnO nanoparticles, and then the structural, optical and surface morphological properties were investigated by XRD, HRTEM, FESEM, XRF and FTIR analyses. Methods: Fe2O3-ZnO nanoparticles were fabricated by a solgel synthesis method by combining iron chloride hexahydrate and zinc sulfate heptahydrate. In the beginning, 2g of Polyvinylpyrrolidone (PVP) stabilizer was dissolved in 100 mL deionized water and then 5 g FeCl3 was added to the solution with stirring at room temperature. Then 5g of ZnSO4 was added to the solution and synthesis temperature was increased to 100 °C. The product was evaporated for 3 hours, cooled to room temperature and finally calcined at 600 °C for 3 hours. Result: The XRD results showed single-phase Fe2O3-ZnO nanocomposites with a hexagonal wurtzite structure of ZnO and spinel phase of rhombohedral α-Fe2O3. The crystallite size of as-prepared sample was determined at about 45 nm and annealed one was calculated around 40 nm. The SEM images showed that the Fe-Zn nanoparticles changed from spherical shape to rod shape by increasing the temperature after annealing. The TEM studies showed the core-shell nanoparticles with a mean diameter of 47 nm. The sharp peaks in the FTIR spectrum determined the stretching vibrations of Fe and Zn groups in the frequencies of 620, 565 cm-1 and 410 cm-1. Conclusion: The XRD data indicates a single-phase Fe2O3-ZnO structure. The SEM images show that the nanoparticles changed from sphere-like shape to rod-like shape by increasing the annealing temperature. TEM image exhibits the core-shell Fe-Zn nanoparticles with an average diameter of about 37 nm. From the FTIR data, it is shown that the presence of Fe-Zn stretching mode and the intensity of the peaks increased by increasing the annealing temperature. XRF analysis showed peaks of iron and ferrite elements, and an increase in the Zn weight percent was observed from 26.35 %Wt. to 49.26 %Wt. with increasing temperature.

Photodetectors for weak signal conditions from Au/Cu co-doped ZnO

Here, we have used a simple method for polyol synthesis, analysis, and testing of Au/Cu-doped ZnO Ultraviolet (UV) photodetectors (PD). Our results are reported and discussed by X-ray diffraction (XRD) to ensure that the manufactured samples show a hexagonal wurtzite ZnO structure. Transmission electron microscopy (TEM) confirmed the nanoparticle growth in the hexagonal sample on the surface, which is the key to improving the light response. Our prepared UV PD Au/Cu codoped ZnO showed a rapid time at a power density of 7.6 mW. the highest responsivity of R = 575 mA/W and sensitivity 103 obtained at 7.6 mW with an applied voltage of 1 V. Our results demonstrate the obvious substitution of Au and Cu in ZnO, thereby improving the UV-sensing light response.

Ultrasound-enhanced biosynthesis of uniform ZnO nanorice using Swietenia macrophylla seed extract and its in vitro anticancer activity

Abstract In this study, ultrasonically driven biosynthesis of zinc oxide nanoparticles (ZnO NPs) using Swietenia macrophylla seed ethyl acetate fraction (SMEAF) has been reported. X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analyses confirmed the presence of a pure hexagonal wurtzite structure of ZnO. Field emission scanning electron microscope images revealed the formation of uniquely identifiable uniform rice-shaped biologically synthesized ZnOSMEAF particles. The particle sizes of the biosynthesized NPs ranged from 262 to 311 nm. The underlying mechanisms for the biosynthesis of ZnOSMEAF under ultrasound have been proposed based on FTIR and XRD results. The anticancer activity of the as-prepared ZnOSMEAF was investigated against HCT-116 human colon cancer cell lines via methyl thiazolyl tetrazolium assay. ZnOSMEAF exhibited significant anticancer activity against colon cancer cells with higher potency than ZnO particles prepared using the chemical method and SMEAF alone. Exposure of HCT-116 colon cancer cells to ZnOSMEAF promoted a remarkable reduction in cell viability in all the tested concentrations. This study suggests that green sonochemically induced ZnO NPs using medicinal plant extract could be a potential anticancer agent for biomedical applications.

Influence of isovalent Cd doping concentration and temperature on electric and dielectric properties of ZnO films

In this study, pure zinc oxide and lightly cadmium doped zinc oxide (Zn1-xCdxO; x = 0.01, 0.03, 0.05 and 0.07) films were synthesized by chemical bath deposition to mainly investigate the possible impact of isovalent (in particular Cd) doping ratio and temperature on their electric and dielectric features. X-ray diffraction patterns revealed that all produced films have a dominance of ZnO hexagonal wurtzite structure with the emergence of a minor CdO cubic phase at x ≥ 0.03, and predicted the decrease in average crystallite sizes with Cd doping. Cd content in the films was verified by energy dispersive X-ray analysis. Images of scanning electron microscopy revealed the formation of nanorods and spheres on the surface of pure ZnO film which changed to porous/agglomerative spheres with Cd doping. Then a comprehensive electric and dielectric analysis was carried out as a function of frequency in a wide temperature range (300–700 K) using two separate experimental data sets, (Z, θ) and (C, G). The results demonstrated the critical effect of temperature and Cd doping ratio on the electrical and dielectric properties of ZnO films. Among the investigated films, Zn0·97Cd0·03O film recorded highest conductivity and enhanced dielectric properties which was attributed to the equal activation of grains and grain boundaries in the film structure verified by the estimation of activation energies from impedance spectrum. However, the effect of Cd doping on electric and dielectric properties was prominent only below 500 K, beyond which the doping effect became negligible which might be correlated with the effective dominance of grain boundaries at high temperatures as was witnessed by modulus spectrum.

Enhanced optoelectronic properties of Ti-doped ZnO nanorods for photodetector applications

We report the effect of Ti-doping on structural, morphological, photoluminescence, optical and photoconductive properties of ZnO thin films. Pure and Ti(1, 3 and 5%)-doped ZnO thin films are deposited by the successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction analysis revealed the single-phase hexagonal wurtzite ZnO structure of all the films. Scanning electron microscope images suggest the formation of rod shaped particles in Ti-doped ZnO thin films. Photoluminescence spectra of all the films show emission peaks centered at 398 nm, 413 nm, 438 nm, 477 nm and 522 nm wavelengths. Optical properties support the semiconducting nature of all the films. The optical bandgap values are estimated to be 3.29 eV, 3.26 eV, 3.19 eV and 3.23 eV for ZnO, ZnO:Ti(1%), ZnO:Ti(3%) and ZnO:Ti(5%) thin films, respectively. Photoconductivity study indicates that ZnO:Ti(3%) thin film exhibits high responsivity, external quantum efficiency and detectivity of 0.30 AW-1, 97% and 5.49 × 1010 Jones, respectively, among all the films. The enhanced photoconductivity of Ti-doped ZnO thin films make them useful for optoelectronic applications.

Microstructure and anti-corrosion properties of spray pyrolyzed Ni-doped ZnO thin films for multifunctional surface protection applications

The microstructures, electrochemical, and hardness properties of deposited Ni-doped ZnO thin films on ultrasonically cleaned 316L stainless steel (316L ST) employing a low-cost chemical spray pyrolysis technique (CSPT) was examined in this work. The films were prepared at various concentrations using commercially available purity zinc acetate and nickel acetate as the precursor sources. The result of x-ray diffractometry (XRD) showed that the films have polycrystalline structure with all the films consisting of single phase ZnO hexagonal wurtzite structure. Scanning electron microscopy (SEM) result affirmed that the coated films adhered to the substrates and equally spread through the substrate surfaces. The surface microstructure of the 316L ST improves with Ni content. The corrosion resistance of the 316L ST was observed to improve with the coated films. Hardness value of the uncoated 316L ST was observed to increase from 139.15 HV to 233.03 HV of coated S3 (9% nickel acetate (0.2 M) and 91% zinc acetate (0.2 M)).