Zinc Oxide Nanofilms Research Articles

Impact of Low Iron Doping on the Structural, Optical, and Magnetic Properties of Zinc Oxide Nanofilms for Spintronic Applications

Impact of Low Iron Doping on the Structural, Optical, and Magnetic Properties of Zinc Oxide Nanofilms for Spintronic Applications

Optical and electrical properties of zinc oxide nanofilms deposited using the sol-gel method

This paper is aimed at investigation of electrical properties inherent to zinc oxide (ZnO) nanofilms prepared using the sol-gel method. The experimental samples consisted of a substrate (25×25×1 mm) made of microscopic glass brand “Voles” covered with the above films of the thickness ranging from 50 to 150 nm. Optical characterization was performed to calculate the bandgap width and to confirm the presence of zinc oxide in the nanofilms and demonstrate their optical activity. An oscillographic method was used to measure the surface resistance of nanofilms by using a galvanic elastic contact, which allowed determining their high electrical quality and resistance. Simultaneously, the high mechanical strength of these nanofilms was ascertained under the action of the elastic contact, enduring a series of 5 to 10 measurements without noticeable changes in resistance. Measurements were also carried out to observe the change in the electrical resistance of ZnO films, when they were heated from 25 up to 100 °C. The obtained results have indicated the potential of these nanofilms for applications in the fields of electronics, photoelectronics and sensor technologies.

Fully Printed Flexible Zinc Oxide Patch for Wearable UV Light Sensing

AbstractMetal oxide materials are widely adopted in UV sensing due to their advantages of reliability, stability, and high sensitivity. However, the fabrication of metal oxide films on flexible substrates using micro/nano printing techniques still poses challenges. Notably, inks containing oxide nanoparticles often lead to nozzle clogging during the printing process. In addition, methods relying on precursor solutions typically require high post‐processing temperatures that conventional flexible substrates cannot withstand. In this study, a novel precursor ink based on zinc amine hydroxide complexes is proposed, enabling post‐processing at a low temperature of 250 °C. Through a fully printed approach, a wearable UV sensor based on a zinc oxide nanofilm on a flexible substrate is successfully fabricated. The sensor exhibits outstanding sensitivity and rapid response characteristics. By incorporating silver nanoparticles into the ink, the baseline resistance of the sensitive material is adjusted. Furthermore, a smart patch utilizing the NFC communication protocol is developed, allowing for wireless, passive, and wearable UV detection. In this study, a process paradigm for fabricating metal oxide films on flexible substrates using micro/nano printing techniques is introduced, showcasing significant potential in the field of micro/nano sensor fabrication.

Distinct Optical and Structural (Nanoyarn and Nanomat-like Structure) Characteristics of Zinc Oxide Nanofilm Derived by Using Salvia officinalis Leaves Extract Made without and with PEO Polymer

This paper reports the optical properties of zinc oxide nanofilm fabricated by using organic natural products from Salvia officinalis leaves (SOL) extract and discusses the effect of the nanocrystal (NC) structure (nanoyarn and nanomat-like structure) on nanofilm optical properties. The surface-active layer of the nanofilm of ZnO nanoparticles (ZnO NPs) was passivated with natural organic SOL leaves hydrothermally, then accumulated on zinc oxide nanorods (ZnO NRs). The nanofilms were fabricated (with and without PEO) on glass substrate (at 85 °C for 16 h) via chemical solution deposition (CSD). The samples were characterized by UV-vis, PL, FESEM, XRD, and TEM measurements. TEM micrographs confirmed the nucleation of ZnO NPs around 4 nm and the size distribution at 1.2 nm of ZnO QDs as an influence of the quantum confinement effect (QCE). The nanofilms fabricated with SOL surfactant (which works as a capping agent for ZnO NPs) represent distinct optoelectronic properties when compared to bulk ZnO. FESEM images of the nanofilms revealed nanoyarn and nanomat-like structures resembling morphologies. The XRD patterns of the samples exhibited the existence of ZnO nanocrystallites (ZnO NCs) with (100), (002), and (101) growth planes. The nanofilms fabricated represented a distinct optical property through absorption and broad emission, as the optical energy band gap reduced as the nanofilms annealed (at 120 ℃). Based on the obtained results, it was established that phytochemicals extracted from organic natural SOL leaves have a distinct influence on zoic oxide nanofilm fabrication, which may be useful for visible light spectrum trapping. The nanofilms can be used in photovoltaic solar cell applications.

Atomic Layer Deposition of Chlorine Containing Titanium–Zinc Oxide Nanofilms Using the Supercycle Approach

Atomic layer deposition (ALD) is a useful tool for producing ultrathin films and coatings of complex composition with high thickness control for a wide range of applications. In this study, the growth of zinc–titanium oxide nanofilms was investigated. Diethyl zinc, titanium tetrachloride, and water were used as precursors. The supercycle approach was used, and wide ZnO/TiO2 (ZTO) ALD cycles were prepared: 5/1, 3/1, 2/1, 1/1, 1/2, 1/3, 1/5, 1/10, 1/20. Spectral ellipsometry, X-ray reflectometry, X-ray diffraction, scanning electron microscopy, SEM-EDX, and contact angle measurements were used to characterize the thickness, morphology, and composition of the films. The results show that the thicknesses of the coatings differ considerably from those calculated using the rule of mixtures. At high ZnO/TiO2 ratios, the thickness is much lower than expected and with increasing titanium oxide content the thickness increases significantly. The surface of the ZTO samples contains a significant amount of chlorine in the form of zinc chloride and an excessive amount of titanium. The evaluation of the antibacterial properties showed significant activity of the ZTO–1/1 sample against antibiotic-resistant strains and no negative effect on the morphology and adhesion of human mesenchymal stem cells. These results suggest that by tuning the surface composition of ALD-derived ZTO samples, it may be possible to obtain a multi-functional material for use in medical applications.

Investigation of optical properties of zinc oxide nanofilms deposited by electrodeposition technique

Zinc oxide (ZnO) nanofilms were synthesized by electrochemical deposition from a simple aqueous zinc chloride onto indium tin oxide (ITO) substrate. Chronoamperometry experiments were performed to deposit nanofilms at the cathodic potential −1.0 V and time 5000 s at 70°C. Diffraction measurements of x-ray showed the hexagonal wurtzite structure of the as-grown nanofilms and the preferred orientation was along the (002) axis. A well-defined ZnO morphology was generated under −1.0 V for 1000 s on ITO glass. Atomic force microscopy observations explored the effect of electrode coating technique on the microscale ZnO nanofilms. The optical constants and thickness of nanofilms were determined with high precision using spectroscopic ellipsometry. The measurements of photoluminescence demonstrated two emission peaks; the first of which was related to excitonic emissions at about 392 nm, referring to the band gap of ZnO, and the second was related to oxygen vacancies ionized singly at about 490 nm.

Nonclassical crystallization of zinc carbonate hydroxide hydrate nanofilm mediated by calcium ions

To satisfy the demand of zinc oxide (ZnO) with advanced muti-functional properties, significant efforts have been made in synthesizing ZnO with various structure and morphology. In particular, hydrothermal method has attracted considerable attentions, in which Zn4CO3(OH)6·H2O (ZCHH) is commonly found as a metastable precursor. However, the formation and crystallization mechanisms of ZCHH are still lacking and urgently needed. In the present study, the crystallization pathway of ZCHH was systematically investigated, and the results demonstrate that the amorphous zinc carbonate (AZC) was an even more unstable precursor. AZC nanoparticles typically aggregated to form one-dimensional (1D) ZCHH nanorods, however, two-dimensional (2D) ZCHH nanofilms were obtained in the presence of a certain concentration of calcium ion. The results suggest that calcium ions could promote the partial dissolution of AZC and facilitate the aggregation of AZC nanoparticles to form crystalline nanofilm. Moreover, 2D ZnO nanofilms could be obtained by heat treatment of the ZCHH nanofilms. The calcium ion mediated nonclassical crystallization pathway provides inspiration for fabrication of ZnO with controlled morphology and offers new opportunities for inorganic regulated material synthesis.

ГИДРОТЕРМАЛЬДЫ ӘДІСПЕН МЫРЫШ ОКСИДІНІҢНАНОСТЕРЖЕНЬДЕРІН АЛУ

Thin films of zinc oxide (ZnO) are very promising for thin-film transistors, solar panels, sensors and optoelectronic devices. The article presents the structural properties and morphology of zinc oxide (ZnO) obtained by hydrothermal synthesis. ZnO nanofilms (as a seed layer) were deposited by the sol-gel method on the glass surface of STO. The results of the experiment showed that the concentration of chemical reagents in the process of sol-gel transformation has a strong effect on the properties of ZnO films. Samples of ZnO nanorods on the surface of the nanofilm were obtained by hydrothermal method at a solution temperature of about 97 ° C for 3 hours.After firing the synthesized ZnO nanorods, the electrical resistance increased several times. The chemical composition and morphology of the obtained nanorods arrays were characterized by scanning electron microscopy and X-ray diffraction. As a result of the study, arrays of ZnO nanoparticles showed a highly improved response to visible light. The results of the article can be used in other combinations of metal oxides, and also offer many interesting opportunities for further development of high-performance photoelectrochemical devices for solar energy conversion. The results of scientific research are the most important material data for alternative energy and can be used by industry specialists in the creation of photoelectrochemical systems for generating hydrogen fuel with the formation of active photanode layers of water decomposition systems with zinc oxide.

Nanometric lamination of zinc oxide nanofilms with gold nanoparticles for self-perceived periodontal disease sensors

Since methyl mercaptan (CH 3 SH) concentration from exhaled breath increases marginally by the progress of periodontal disease, the design of a sensing materials that can selectively and accurately discriminate ppb-level CH 3 SH among volatile sulfur compounds (VSCs) continue to be strongly demanded for the early diagnosis of periodontitis . Here, the primarily aim is to propose self-perceived-periodontal disease sensors by strategic nanometric lamination of 30 nm-thick ZnO nanofilms with 3 nm-thick Au nanoparticles (NPs) through the two-step process composed of atomic layer deposition and thermal evaporation techniques. Comprehensive microscopic and spectroscopic analysis corroborate the structural and chemical features of ZnO hybridized with Au NPs. The ZnO laminated with Au NPs optimized through size and density control enables to lead the significant enhancement of the gas sensing performance with 4.99% of gas response for 50 ppb of CH 3 SH and a detection limit down to 50 ppb. It was highlighted that highly selective detection of ppb-level CH 3 SH under a H 2 S atmosphere was validated by the Au NP-incorporated ZnO hybrid sensors with reliable and reproducible gas sensing performance. • Periodontal disease sensors were realized using ZnO nanofilms with Au NPs. • The structural and chemical features of the films were comprehensively examined. • The Au NPs-incorporated ZnO sensors showed enhanced sensing performance. • Highly selective detection of ppb-level CH 3 SH was accomplished.

Studies of Zinc and Zinc Oxide Nanofilms of Different Thickness Prepared by Magnetron Sputtering and Thermal Oxidation

Studies of Zinc and Zinc Oxide Nanofilms of Different Thickness Prepared by Magnetron Sputtering and Thermal Oxidation

Research on the Application of Physical Properties of Optoelectronic Films in Passive Devices for Optical Communications

Thin films play an important role in modern science and technology. With the development of optical fibre communication technology and laser technology, thin films are used more and more widely in this field. The application of optical film in optical communication and laser technology is introduced systematically. The application of optical films in optical communications basically covers a variety of conventional optical films. Based on this research background, the paper mainly analyses the optical and physical properties of zinc oxide nano-films and discusses its application in optical communication.

Naphthalenothiophene imide-based polymer exhibiting over 17% efficiency

Summary Developing novel electron-deficient monomers is crucially important for the future development of non-fullerene organic solar cells. Here, we report a new electron-deficient monomer naphthalenothiophene imide (NTI) and NTI-based copolymers PNTB and PNTB-2T. The strong electron-withdrawing ability of NTI could effectively lower the HOMO level of the polymer that facilitates the tuning of the polymer’s physical properties while simultaneously maintaining the low-lying HOMO value. Polymer chains modification by introducing extra thiophenes results in the closed π−π stacking and ordered polymer chain packing of PNTB-2T and is proven to be an effective strategy to increase the device performance. Thus, solar cell devices for PNTB-2T:Y6 exhibit an efficiency of 16.72%, which is further enhanced to 17.35% by the third component PC71BM, whereas that for PNTB:Y6 is only 3.81%. Importantly, PNTB-2T-based devices exhibit excellent batch-to-batch reproducibility. These features make this family of polymer donors very promising and the design strategies will enlighten future development of high-performance polymer donors for organic solar cells (OSC).

Studies of Zinc and Zinc Oxide Nanofilms of Different Thickness Prepared by Magnetron Sputtering and Thermal Oxidation-=SUP=-*-=/SUP=-

Polycrystalline zinc films with the thickness of about 20, 40, 60, and 80 nm and mainly granular morphology comprising nearly spherical particles involving hexagonal crystals are obtained by magnetron sputtering on cover glass supports. Subsequently, the prepared layers were subjected to thermal oxidation in the air to obtain transparent zinc oxide layers. The synthesized films are studied by SEM and UV-vis spectroscopy. Based on the obtained spectra, optical properties of the layers are studied as a function of their thickness. The optical band gap Eg for the films with the thickness from 40 to 80 nm is estimated on the level about 3.28 eV similar to the reference value 3.3 eV for bulk zinc oxide, while for the thickness of 20 nm Eg slightly drops to about 3.24 eV. Keywords: zinc; zinc oxide; nanolayers; magnetron; oxidation; surface morphology; transparency; optical bandgap.

Gas sensing properties of palladium-modified zinc oxide nanofilms: A DFT study

The improved gas-detecting ability of ZnO nanostructures has generated considerable attention for further development based on a unique and practical approach. However, reduced gas sensitivity and selectivity, as well as the sophisticated synthesis requiring high-cost technology restricts its efficient use. In this regard, the enhancement of gas sensing properties can be brought about by incorporating the noble metal palladium (Pd) to modify the ZnO surface. This work applied density functional theory (DFT) calculations to study such sensing materials to the target gases (i.e., hydrogen (H2) and ethanol (C2H5OH)), which are extensively applied in energy production, thereby requiring rapid and accurate detection. The modified ZnO thin film-based gas sensor was modeled into Pd-substitutional doped and Pd-decorated ZnO surfaces. The charge transport phenomenon at the atomic scale, binding strength, and other electronic and structural properties were elucidated as the varied number of Pd. Pd-decorated ZnO surfaces enhance the sensitivity of both molecules. The calculation results could provide an atomistic insight and a better understanding of altered electrical and sensing properties of ZnO surface modification by Pd atoms.

Influence of aluminum doping on microstructure, optical and electrical properties of c axis oriented zinc oxide nano films prepared by nebulizer spray pyrolysis technique

Transparent conducting aluminum-doped ZnO thin films have been prepared by nebulizer spray pyrolysis technique for different doping concentrations on glass substrates. X-ray diffraction patterns reveal that all the films are polycrystalline of hexagonal structure with c–axis orientations. Atomic force microscopy (AFM) images noticed that the films have a uniform surface morphology consist spike shaped particles and low surface roughness. The optical transmittance in visible region was escalated from 85 to 93% and optical band gap of thin films is also improved from 3.27 to 3.37 eV. Photoluminescence spectra show mainly five emissions peaks and a blue shift observed in UV emission peak. Hall Effect measurements show that the prepared films having n-type conductivity with low resistivity and high carrier concentrations.

Enhancement in structural, morphological and optical features of thermally annealed zinc oxide nanofilm

This paper presents the study of surface morphological, optical and microstructural features of zinc oxide (ZnO) nanofilm layered upon p-type Si substrate of <100> orientation by employing conventional RF magnetron sputtering system at different annealing temperatures. The effect of annealing on the nano-film is examined using different characterization techniques such as Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), FTIR (Fourier Transform Infrared Spectroscopy), UV-vis spectroscopy and Raman spectroscopy. The sharp diffraction peak at (002) orientation is seen by the XRD spectra which signifies a better growth of single crystalline thin film along the z-axis with the hexagonal wurtzite crystal structure. The surface morphological study shows that the grain size of the thin film intensifies from 22.06 nm to 36.77 nm when the annealing temperature is increased whereas there is a decrease in the values of lattice constants (a=b, c), FWHM (full width at half maximum), residual stress, lattice strain and dislocation density by increasing annealing temperature. The enhancement in the grain size makes the thin film appropriate for MEMS device applications including piezoelectric energy harvesters, gas sensors, etc. The optical bandgap of the ZnO thin film is estimated using Kubelka-Munk (KM) approach and it decreases from 3.23 to 3.16 eV for As-deposited, 400 °C, 600 °C and 800 °C respectively which makes the annealed thin film apposite for optoelectronic device applications. The intensity of the Raman peaks strengthens with the annealing temperature. These results prove that the annealing extensively enhances the crystallinity, structural, morphological and optical features of ZnO thin film and hence becomes suitable for nanoelectronic device applications.

Gallium-doped zinc oxide films with diverse nanomorphologies grown via sol–gel united spin coating technique

Some gallium-doped zinc oxide nanofilms (GZONFs) with diverse morphologies were produced on the p-type Si (100) substrate by the sol–gel united spin coating. The thermally annealed nanofilms were characterized using different techniques to determine the influence of various Ga contents (0–5%) on their structures, morphologies, optical and electrical characteristics. The XRD patterns of the as-prepared nanofilms displayed the existence of the single-phase polycrystalline particles with varying sizes (55–36 nm). The band gap values of these GZONFs were ranged from 3.227–3.269 eV. The nanofilm produced with 1% of Ga exhibited the minimal electrical resistivity ≈ 4.6429 × 10–3 Ω cm, highest carrier density ≈ 1.37648 × 1020 cm−3 and Hall mobility ≈ 9.779 cm2/V s. It was shown that the overall properties of the proposed GZONFs can be customized by adjusting the concentration of Ga doping.

Immobilized ZnO nano film impelled bacterial disintegration of dairy sludge to enrich anaerobic digestion for profitable bioenergy production: Energetic and economic analysis

Proper treatment and disposal of sludge is a substantial task around the biosphere. To address this issue, sludge deflocculation using photocatalyst was opted to enhance bacterial disintegration which in turn accelerate sludge digestion anaerobically. During this investigation, Direct current (DC) sputtering together with annealing process was used to immobilize Zinc oxide (ZnO). This immobilized ZnO removes the extracellular components at 15 min. The deflocculation mediated bacterial pretreatment induced 22.9% of soluble organics solubilization which auguments the biodegradability to 0.195 g COD/g COD during anaerobic digestion. The quantity of methane generated by deflocculated sludge was 39.2% higher than sludge with bacterial disintegration only with maximum methane yield of 437.14 mL/g COD. Hence, the outcome of the proposed work confirmed that the method is scalable with a net profit of 27 USD with the maximum methane generation of 413.1 kWh. Additionally, this method reduced 57% of dry sludge (solid).

Investigation on the optical transmission in UV range of sol-gel spin coated zinc oxide nanofilms deposited on glass

Physical properties of semiconductor thin films change when reducing their thicknesses from micro- to nanoscales. Indeed, zinc oxide (ZnO) microfilms absorb ultraviolet (UV) light; however, the optical transmission of the ZnO nanofilms shows double transmission edges in the same range of wavelengths. In the present work, we deposited ZnO nanofilms on glass substrates by sol–gel spin coating method. We carried out grazing incidence X-ray diffraction (GIXRD), where results showed that elaborated ZnO nanofilms have wurtzite structure, with dominance along (100), (002) and (101). A bruker profilometer gives a thickness about 119 nm. The photoluminescence at room temperature of films carried out with Horiba iHR 550 shows a strong luminescence in visible range. The ZnO nanofilms showed high optical transmission in the UV and the visible ranges with a drop of about 50% in the wavelengths range of 300-400 nm. The high optical transmission observed in the UV range was explained by photoluminescence.

Aroma Detection of Ethanol Content in Fruits Using ZnO Doped Nano Thin Films

The nano materials of Zinc Oxide (ZnO) were studied to exhibit excellent properties of semi conductors and are also used as nano wires and nano rods in varied applications. In the fields of aroma sensors, Zinc Oxide acts as a very good gas sensing agent. The Zinc Oxide has properties of changing electrical conductivity and resistance values when exposed to gas sensing atmosphere. This experimental research is to identify the changes in the resistivity values when exposed to ethanol vapors at different vapor pressures. The Zinc Oxide nano films are designed by dip coating process, which results in different resistance values when exposed on the ethanol vapors. The prepared thin film of Zinc Oxide is capable of detecting the presence of ethanol vapors when doped with PVA (poly vinyl alcohol) at 3% concentration. This produces efficient results and detects the presence of ethanol even at high and low vapor pressure.