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The Effect of the Thickness and Oxygen Ratio Control of Radio-Frequency Magnetron Sputtering on MgZnO Thin-Film Transistors
摘要： In this study, we use silicon dioxide for a magnesium-zinc-oxide thin-film transistor gate dielectric layer, controlling the thickness of the active layer and the Mg content of the film by radio-frequency (RF) sputtering. With an ideal thickness, a magnesium-zinc-oxide thin-film transistor can function normally. As the active layer thickness is controlled at 10 nm and the sputtering oxygen-flow rate is controlled at 14% to properly compensate for the oxygen vacancies, we can obtain the best features. The result of the analysis showed a field-effect mobility of 5.65 cm2/V · s, a threshold voltage of 3.1 V, a subthreshold swing improved to 0.80, and a current-switch ratio of over five orders of magnitude.
关键词： RF Sputtering,Magnesium Zinc Oxide,Thin-Film Transistor
更新于2025-09-09 09:28:46
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Synthesis, Characterization and Photocatalytic Efficiency of ZnO/MWCNT Nanocomposites Prepared Under Different Solvent Conditions
摘要： Here we report the application of zinc oxide (ZnO) coated multi-walled carbon nanotube (MWCNT) composites in the photocatalytic decomposition of acetaldehyde (AA). Zinc oxide nanoparticles were successfully coated on the multi-walled carbon nanotube via impregnation process using zinc acetate (Zn(CH3COO)2 × 2H2O) as precursor and sodium dodecyl sulfate (SDS) treated multi-walled carbon nanotube as raw material under different solvent conditions. The applied solvents during preparation were ethanol (EtOH) and water (H2O). As-prepared materials were characterized by thermal analysis (TG), X-ray diffraction (XRD), specific surface area measurement (BET) and transmission electron microscopy (TEM) techniques. Photocatalytic efficiencies of as-prepared composites were investigated in a stationary reactor equipped with UV lamp. Decomposition of acetaldehyde was followed by using gas chromatography (GC). Observations revealed that using impregnation method and different solvents the preparation of ZnO/MWCNT nanocomposites can be controlled easily. The highest degradation rate was achieved with the nanocomposite was synthetized using ethanol as solvent. The photocatalytic experiments revealed that the composite has higher photocatalytic activity than that of both the zinc oxide nanoparticles and the mechanical mixture of multi-walled carbon nanotube and zinc oxide.
关键词： Transmission Electron Microscopy,Zinc Oxide,Photocatalysis,Gas Chromatography,Nanocomposite
更新于2025-09-09 09:28:46
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Sonochemical syntheses of iron doped zinc oxide nanoparticles at different sonication powers and temperatures with their application for photocatalytic degradation of PVC-ZnO composite film
摘要： Doping with iron enhances various properties of zinc oxide making it suitable for several applications. Sonochemical route is an easy way for synthesis of doped ZnO nanoparticles. Input-powers of ultrasound and synthesis–temperature have significant influences over the characteristics of iron-doped zinc oxide nanoparticles. Effects of the varying sonication powers and synthesis temperatures on the average grain size, band gap and magnetic properties of doped ZnO were studied using UV-vis spectrophotometer, X-ray diffraction (XRD), field emission scanning electron micrography (FESEM) with Energy dispersive X-ray spectroscopy (EDX) and SQUID-magnetometer. Both temperature and sonication power influenced the characteristics. The nanoparticles were then used for casting composite films with polyvinyl chloride (PVC) and photodegradation of the film was examined under sunlight. Performances of nanoparticles synthesised at different conditions were compared. Maximum degradation of about 12% was obtained within three hours with nanoparticles synthesised at 42 W power and 30°C temperature.
关键词： sonication-power,temperature,Fe-doped zinc oxide,nanoparticles,photocatalyst,degradation,ultrasound,PVC-nanocomposite,bandgap,magnetization,characterisation
更新于2025-09-05 23:13:11
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8.1: <i>Invited Paper:</i> Enhanced Elevated-Metal Metal-Oxide Thin-Film Transistor Technology
摘要： Enhancement to the elevated-metal metal-oxide (EMMO) thin-film transistor (TFT) architecture employing annealing-induced source/drain regions is presently reported, thus further extending the advantage of EMMO over the conventional TFT architectures. The enhancement includes: a 3-mask process resulting in a reduced mask-count, hence manufacturing cost; a bottom-gate self-aligned process resulting in reduced parasitic overlap capacitance, hence signal delay; and a 300-oC process, with the lower temperature offering better compatibility with a wider range of flexible substrates.
关键词： Annealing-Induced Source and Drain,Self-Aligned,Elevated-Metal Metal-Oxide,Flexible Substrate,Indium-Gallium-Zinc Oxide,Mask-Count,Thin-Film Transistor
更新于2025-09-04 15:30:14
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Facile Synthesis of ZnO Nanorods/GO Composite and Its Optical Performance
摘要： The ZnO nanorods/GO composite was fabricated by facilely covering monolayer or few-layer graphene oxide (GO) film on the uniformly distributed ZnO nanorods, which was synthesized on Si substrate using a solution method. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), as well as X-ray diffraction (XRD). The photoluminescence (PL) measurement indicates that the ZnO nanorods have a strong ultraviolet (UV) emission centered at ～391 nm attributed to the recombination of free excitons and a defect-related visible emission centered at ～530 nm. After the nanorods were covered with GO film, the PL intensity of the composite is quenched compared to that of the bare one at the same excitation condition. The fluorescence quenching mechanism suggests that there is an interfacial charge-transfer process between the excited ZnO and the GO film, and the composite fabricated in this experiment be possible to improve the photocatalysis performance.
关键词： Photocatalyst,Nanorod Array,Zinc Oxide,Graphene Oxide,Fluorescence Quenching
更新于2025-09-04 15:30:14
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Synthesis and Characterizations of Zinc Oxide on Reduced Graphene Oxide for High Performance Electrocatalytic Reduction of Oxygen
摘要： Electrocatalysts for the oxygen reduction (ORR) reaction play an important role in renewable energy technologies, including fuel cells and metal-air batteries. However, development of cost effective catalyst with high activity remains a great challenge. In this feature article, a hybrid material combining ZnO nanoparticles (NPs) with reduced graphene oxide (rGO) is applied as an efficient oxygen reduction electrocatalyst. It is fabricated through a facile one-step hydrothermal method, in which the formation of ZnO NPs and the reduction of graphene oxide are accomplished simultaneously. Transmission electron microscopy and scanning electron microscopy profiles reveal the uniform distribution of ZnO NPs on rGO sheets. Cyclic voltammograms, rotating disk electrode and rotating ring disk electrode measurements demonstrate that the hierarchical ZnO/rGO hybrid nanomaterial exhibits excellent electrocatalytic activity for ORR in alkaline medium, due to the high cathodic current density (9.21 × 10?5 mA/cm2), positive onset potential (?0.22 V), low H2O2 yield (less than 3%), and high electron transfer numbers (4e from O2 to H2O). The proposed catalyst is also compared with commercial Pt/C catalyst, comparable catalytic performance and better stability are obtained. It is expected that the ZnO/rGO hybrid could be used as promising non-precious metal cathode in alkaline fuel cells.
关键词： reduced graphene oxide,zinc oxide,non-precious-metal catalyst,oxygen reduction reaction
更新于2025-09-04 15:30:14
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ZnO-coated SiO2 nanocatalyst preparation and its photocatalytic activity over nitric oxides as an alternative material to pure ZnO
摘要： Core-shell nanospheres, CSNp, consisting of silica as a core and zinc oxide as a shell were prepared via a simple and environmentally friendly procedure. Silica cores with a mean diameter of 300 nm were prepared through the hydrolysis-condensation reactions in the presence of hyperbranched poly(ethylene)imine (HBPEI) followed by calcination and chemical surface modi?cation with the use of HBPEI. To fabricate the core-shell structure, various amounts of zinc nitrate hexahydrate were precipitated using the carboxymethyl poly(ethylene)imine polymer (Trilon P) as a precipitator. To this suspension, the as synthesized modi?ed silica powder was added with the aim to develop electrostatic bonds between the carboxyl groups of TRILON P and the amino groups of the cationic HBPEI polymer. The optimization of processing parameters led to the development of homogeneous core-shell structures bearing a well-developed nanocrystalline zinc oxide shell over each silica core. The material with the optimum shell showed excellent photocatalytic activity over nitric oxides as the photocatalytic yield reached 72.9%.
关键词： Core-shell,Photocatalysis,Silicon oxide,Nitrogen oxides,Zinc oxide
更新于2025-09-04 15:30:14
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Spin coated multilayered CuO/ZnO films with high output power under irradiation
摘要： Thin films of pure CuO, pure ZnO and CuO/ZnO multilayers were synthesized using the spin coating technique. CuO and ZnO layers were spin coated for 30 s at speeds of 2000 and 1500 rpm, respectively. All the samples were subsequently annealed at 500 0C for one hour in air. Structural properties of films investigated using XRD patterns indicated the crystallization of single phase of CuO and ZnO. Optical band gaps of samples determined by UV-Visible spectrums were in the range of the band gaps of CuO and ZnO. The main objective of the preparation of multilayered CuO/ZnO was enhancing the output power by combining wide band gap and narrow band gap materials. CuO with higher photocurrent and ZnO with higher photovoltage were employed to achieve this task. Photocurrent, photovoltage and impedance were measured in order to investigate the electrical properties of these samples. A liquid junction photocell with electrolyte potassium iodide (KI) was employed to measure photovoltaic properties. A multilayer with ZnO as the top layer provides a higher output power of 3.6 μW/cm2 compared to the output power of a multilayer with CuO as the top layer (1.1 μW/cm2). This is the highest output power reported for a multilayer of CuO/ZnO without any dye coating in KI electrolyte. The highest output power of our multilayered samples is more than twice the previously reported highest output powers of pure CuO and pure ZnO thin film samples without dye coating. Chemical properties of samples were confirmed by FTIR. Crystallite sizes were in the range from 23 to 28 nm. Impedance curves of the samples were measured under dark and light conditions. Two semicircles could be observed at Nyquist plots of both multilayer samples.
关键词： photovoltaic properties,spin coating,XRD,Cupric Oxide,multilayers,Zinc Oxide
更新于2025-09-04 15:30:14
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The enhancement of humidity sensing performance based on Eu-doped ZnO
摘要： In this work, a high performance impedance-type humidity sensor based on Europium-doped ZnO with abundant surface oxygen vacancy defects was synthesized by sol-gel method. Response of the Eu-doped ZnO with di?erent molar ratio were investigated by exposing them to humidity environments in wide range of 11–95% RH at room temperature. The Eu-doped ZnO (2 mol%) exhibits a three orders impedance change, along with short response/recovery time (5 s/19 s), low hysteresis and best linearity. Complex impedance spectra indicates that dopant Eu can enhance humidity sensing performance of ZnO, which is resulted from the introduction of Eu3+ ions into ZnO structure to produce more defects of surface oxygen vacancy and more active sites on the surface of ZnO. The results show that this is a feasible method to achieve high humidity sensing performance by Eu doped ZnO, which make it a promising candidate for humidity sensing materials and broaden the use of ZnO materials.
关键词： Eu dopant,Humidity sensors,Sol-gel,Zinc oxide
更新于2025-09-04 15:30:14
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Photocatalytic Degradation of Methylene Blue using Biosynthesized Zinc Oxide Nanoparticles from Bark extract of Kalopanax septemlobus
摘要： In this study, we applied Kalopanax septemlobus-ZnO nanoparticles (Ks-ZnO NPs) with green approach one-pot synthesis. Further, the extracts were used as capping agent and Zn (OAc)2 as the metal precursor to synthesize ZnO nanoparticles. The formation of ZnO NPs, the surface plasmon resonance were observed at 372 nm in UV-Vis spectroscopy. The presence of functional groups which as a capping agent and formation of ZnO nanoparticles were confirmed in Fourier Transform Infrared Spectroscopy (FTIR) result. The crystallization, elemental mapping and morphology showed by X-ray diffraction (XRD), Field-Emission Transmission Electron Microscopy (FE-TEM), and Energy dispersive X-ray spectroscopy (EDX) respectively. The photocatalytic activity of Ks-ZnO nanoparticles, was determined using Methylene blue dye degradation percentage under UV light irradiation (365nm), which resulted rate constant (k) was found 0.1215 with 97.5% of degradation in 30 minutes. In summary, phytochemicals in K. septemlobus extract have a potential as a reducing agent to form Ks-ZnO nanoparticles. The Ks-ZnO NPs are capable to degrade Methylene blue in brief time due to its extract-capped zinc oxide nanoparticles. Accordingly, the use of K. septemlobus for biosynthesis of nanoparticles may have an advance for many applications as a cost-effective and eco-friendly photocatalyst.
关键词： methylene blue,Kalopanax septemlobus,photocatalysis,nanoparticles,zinc oxide
更新于2025-09-04 15:30:14