- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
ZnO Micro- and Nanostructures Obtained by Thermal Oxidation: Microstructure, Morphogenesis, Optical, and Photoluminescence Properties
摘要： ZnO micro- and nanostructures were obtained through thermal oxidation of Zn powders at high temperature under air atmosphere. A detailed study of the microstructure, morphology, optical, and photoluminescence properties of the generated products at different stages of thermal oxidation is presented. It was found that the exposure time has a strong influence on the resulting morphology. The morphogenesis of the different ZnO structures is discussed, and experimental parameters for fabricating ZnO tetrapods, hollow, core-shell, elongated, or rounded structures by thermal oxidation method are proposed on the basis on the obtained results. Notoriously, the crystal lattice of the ZnO structures has negligible residual strain, although, the density of point defects increases when the thermal treatment is extended; as consequence, their visible luminescence upon UV excitation enhances.
关键词： growth mechanism,ZnO structures,thermal oxidation,physical properties
更新于2025-09-23 15:23:52
-
Influence of thermal oxidation temperature on the microstructure and photoelectrochemical properties of ZnO nanostructures fabricated on the zinc scraps
摘要： In this paper, zinc oxide (ZnO) nanowires were synthesized by thermal oxidation method of zinc scrap at various temperatures ranging between 400 °C and 900 °C under air atmosphere. The influence of different temperature on the phase structures, surface morphologies and photoelectrochemical (PEC) properties of ZnO nanowires were investigated. The characterizations were carried out via X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results showed that annealing temperature played a significant role on surface morphology and phase structure. The band gap energy of the ZnO nanowires changed between 3.12 and 3.194 eV. The photoelectrochemical (PEC) study of the ZnO nanowires was investigated in 0.1 M Na2SO4 aqueous solution. The PEC findings represented that the ZnO nanowire annealed at 600 °C had 252.2 mA/cm2 net photocurrent density which was the best efficiency and at least 10 times higher than that of the lowest one at 1.25 V (vs. VRHE). Mott-Schottky analysis showed that the ZnO nanowires behaved as n-type semiconductor. ZnO nanowire annealed at 600 °C had the highest carrier density value (Nd = 9.03 × 10^23). Moreover, the charge transfer behavior of the ZnO nanowires was determined by means of electrochemical impedance spectroscopy (EIS) measurements. As a result, this work recommends that the ZnO nanowires could be good candidate on PEC applications. Also, thermal oxidation method is an efficient method for fabrication of ZnO nanowires.
关键词： Thermal oxidation,Zn scrap,Electrochemical impedance spectroscopy (EIS),ZnO nanowires,Photoelectrochemical (PEC)
更新于2025-09-23 15:23:52
-
Novel design of photocatalyst coaxial ferromagnetic core and semiconducting shell microwire architecture
摘要： We report a novel design of coaxial core-shell magnetic-semiconductor microwire, as a catalyst under sunlight irradiation. The nano/micro hierarchical architecture-like device is comprised of a coaxial core-shell microwire where the core is the ferromagnetic Fe metal and the shell is formed by a semiconducting hematite layer. The fabrication process of our substrate-free device is simply based on controlled thermal oxidation process revealing a simple and low-cost method. The hematite outer microlayer has a mesoporous structure decorated with nanowires. The ferromagnetic and metallic core assume fundamental importance as to mechanical stability, collect the generated photoelectrons, and to be removed back from the dye solution by a magnetic field gradient or simply a magnet. This nano/micro device has exhibited photocatalytic activity to degrade the methylene blue dye under simulated sunlight irradiation. Additionally, the coaxial magnetic/semiconducting can also be designed as a photoanode to drive water oxidation reaction. The coaxial magnetic/semiconducting photoanode response has shown good chemical stability and long activity under simulated sunlight radiation. In fact, this designed architecture gives novel perspective in the development of substrate free photocatalyst.
关键词： Photoelectrochemical performance,Hematite photoanodes,Photodegradation,Micro/nano architecture,Core-shell microstructures,Thermal oxidation
更新于2025-09-23 15:23:52
-
Effect of thermal oxidation temperatures on the phase evolution and photocatalytic property of tungsten-doped TiO <sub/>2</sub> thin film
摘要： Tungsten-doped titanium dioxide (W-TiO2) thin films were successfully prepared on glass substrates by sputtering thermally oxidized W-doped titanium films in air. Tungsten-doped titanium films were deposited using a DC and RF magnetron cosputtering system. The effects of annealing treatment and W content on the W-TiO2 film microstructure were investigated. The crystalline structures, morphological features, and photocatalytic activity of the annealed W-TiO2 films were systematically studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and ultraviolet spectrophotometry. The results indicated that annealing at 550 °C clearly induced the formation of an anatase and rutile phase mixture in the 5.5 at. % W-TiO2 films, which directly affected photocatalytic activity. The W-TiO2 films showed good photocatalytic activity under UV-light irradiation, with a higher rate of methylene blue dye degradation than in the case of undoped TiO2.
关键词： photocatalytic activity,tungsten-doped titanium dioxide,thermal oxidation,methylene blue degradation,thin films
更新于2025-09-23 15:21:21
-
Optimized Growth of Gallium Oxide Thin Films Using Different Synthesis Processes
摘要： This paper investigates the optimized sputtering conditions for high quality gallium oxide (Ga2O3) thin films while maintaining a strong uniformity within a specific surface area. The research also analyzes the crystal structure and the morphology of gallium oxide (Ga2O3) thin films. We report a comprehensive investigation of two different types of Ga2O3 synthetization processes: (1) direct deposition using radio frequency (RF) magnetron sputter technique and (2) thermal oxidation of gallium nitride (GaN) samples. A detailed comparison is presented in terms of material characterization, surface analysis and electrical performance for each of the synthetization processes. X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and x-ray diffraction (XRD) are employed to study the gallium oxide (Ga2O3) epi-layers on each of the samples. Based on the analysis, Ga2O3 compound is found on all samples with a binding energy ranging from 21 eV to 21.38 eV. Depending on the synthetization process, the thickness varied from 20 nm to 100 nm for RF sputtering process and a maximum of 400 nm for thermal oxidation method. Additionally, the observations revealed that Ga2O3 is formed on the surface, as well as inside the gallium nitride (GaN) film after thermal oxidation. Crystal features are observed on the surface of each of the samples after annealing treatment while XRD analysis showed the presence of the beta (b) polymorph for the annealed samples. After thorough characterization, radio frequency sputtering technique proved to be superior due to its higher purity level and ability to create polycrystalline structures by adding temperature during deposition.
关键词： UHV RF magnetron sputtering,Gallium oxide,thermal oxidation,characterization
更新于2025-09-23 15:21:01
-
Graphene oxide/multia??walled carbon nanotubea??Therminol??66 hybrid nanofluids for lowa??toa??medium temperature volumetric solar collectors
摘要： Nano-composites of graphene oxide (GO) and multi-walled carbon nanotube (MWCNT) were prepared by a simple physical method and well dispersed into Therminol? 66 to form hybrid nanofluids with mass fractions in the range of 10 to 150 ppm. The suspension stability, optical absorption properties and photo-thermal conversion characteristics of GO/MWCNT nanofluids were tested and evaluated. GO nanosheets can avoid the self-entanglement and agglomeration of MWCNTs and ensure long-time suspension stability. The solar energy absorption capability increased with the composite concentration, and the majority of incoming radiation could be absorbed in a fluid layer of 1.5 cm. There existed an optimum concentration of 100 ppm related to the indoor experiment, and the temperature could be increased up to 94°C with the corresponding efficiency improved from 52% (Therminol? 66) to 70% (100 ppm). Besides, a line focusing Fresnel lens was utilized for the outdoor solar concentrating experiment, and the photo-thermal conversion performance of hybrid nanofluids increased with the composite mass fraction from 30 to 100 ppm. A highest temperature of 153°C was achieved at 100 ppm concentration. The thermal oxidation without degradation of Therminol? 66 occurred after indoor/outdoor experiments, and slightly enhanced the optical absorption owing to the solar radiation induced heating effect. The GO-MWCNT/Therminol? 66 nanofluids exhibit a good prospect in volumetric solar thermal systems from low to medium temperatures.
关键词： photo-thermal conversion performance,solar thermal energy,volumetric solar thermal collector,nanofluid,thermal oxidation
更新于2025-09-23 15:19:57
-
Thermal oxidation of sputtered nickel nano-film as hole transport layer for high performance perovskite solar cells
摘要： The effect of rapid oxidation temperature on the sputtered nickel (Ni) films to act as a hole transport layer (HTL) for perovskite solar cell (PSCs) was investigated. A nano-sputtered Ni film with a thickness about 100 nm was oxidized at a range of different oxidation temperatures between 350 and 650 °C to work as HTL in an inverted p–i–n configuration. DC Hall measurement in van der Pauw configuration and photoluminescence spectroscopy were used to measure the charge’s mobility and extraction of nickel oxide (NiO) films. The behaviour of the carrier concentration measurements of NiO layers at different oxidation temperatures showed that the Ni layer oxidized at 450 °C had the highest carrier concentration among the other samples. The performance measurements of the fabricated PSCs showed that the nickel oxide hole-transporting layer which has been oxidized at the optimum oxidation temperature of 450 °C has the highest power conversion efficiency (PCE) of 12.05%. Moreover, the characteristic parameters of the optimum cell such as the open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF) were 0.92 V, 19.80 mA/cm2 and 0.331, respectively.
关键词： Sputtering,Thermal oxidation,Hole transport layer,Perovskite solar cells,Nickel nano-film
更新于2025-09-19 17:13:59
-
Nonaqueous synthesis of TiO2 nanorods using inductively coupled plasma
摘要： Titanium dioxide (TiO2) nanorods are widely used in many fields such as self-cleaning surfaces, photocatalytic lithography and pollutant control, owing to their outstanding physical, chemical and optical properties. Traditional methods for synthesizing TiO2 nanorods are mostly tedious with high cost and tremendous energy consumption. In this work, TiO2 nanorods with excellent optical, electrochemical, and hydrophilic properties were rapidly synthesized on titanium alloy (TC4) by using inductively coupled plasma (ICP) with strong chemical reactivity and high temperature characteristic. XRD patterns and SEM images confirm the conversion of TC4 into rutile TiO2 nanorods after irradiated by ICP at 800 W for only one pass, and the nanorods tend to grow longitudinally under prolonged ICP processing. Moreover, the well-developed single-crystalline feature of TiO2 nanorod is affirmed by TEM test. To reveal the growth mechanism of TiO2 nanorods, three types of substrates (polished TC4 by electrochemical polishing (ECP), polished TA2 by ECP and oxidized TC4 by anodizing) were used to grow TiO2 nanorods. However, TiO2 nanorods with good morphology were only formed on the first type of substrate due to the existence of β phase Ti, which could suppress thermal transmission between grains. In addition, the results of UV–Vis absorption spectrum, electrochemical test, and static water contact angle of the treated TC4 samples show that TiO2 nanorods synthesized by ICP possess excellent optical, electrochemical, and hydrophilic properties.
关键词： Inductively coupled plasma,Hydrophilicity,Optical property,TiO2 nanorods,Thermal oxidation
更新于2025-09-12 10:27:22
-
Fabrication of high photosensitivity nanostructured n-Fe<sub>2</sub>O<sub>3</sub>/p-Si heterojunction photodetector by rapid thermal oxidation of chemically sprayed FeS<sub>2</sub> film
摘要： In this study, we have reported a novel route for the preparation of α-Fe2O3 by rapid thermal oxidation RTO of chemical sprayed FeS2 film at 550°C/20s condition under oxygen ambient. FeS2 to Fe2O3 film after RTO process. Raman shift data of Fe2O3 shows the presence of five Raman active vibration modes indexed to A1g and E1g modes. The dark and illuminated current-voltage properties of n-Fe2O3/p-Si heterojunctions have been investigated in the absence of the buffer layer and the ideality factor of n-Fe2O3/p-Si was 2.7.The responsivity of Fe2O3/Si photodetector was 0.51A/W at 500nm and 0.37A/W at 850nm. The specific detectivity of the photodetector was measured and it was around 60ns.The energy band line-up of n-Fe2O3/p-Si heterojunction was demonstrated under illumination condition.
关键词： Rapid thermal oxidation,Heterojunction,Energy band –line-up,Iron oxide,Iron sulfide
更新于2025-09-11 14:15:04
-
Dynamics Contributions to the Growth Mechanism of Ga2O3 Thin Film and NWs Enabled by Ag Catalyst
摘要： In the last few years, interest in the use of gallium oxide (Ga2O3) as a semiconductor for high power/high temperature devices and UV nano-sensors has grown. Ga2O3 has an enormous band gap of 4.8 eV, which makes it well suited for applications in harsh environments. In this work, we explored the effect of Ag thin film as a catalyst to grow gallium oxide. The growth of gallium oxide thin film and nanowires can be achieved by heating and oxidizing pure gallium at high temperatures (~1000 °C) in the presence of trace amounts of oxygen. We present the results of structural, morphological, and elemental characterization of the β-Ga2O3 thin film and nanowires. In addition, we explore and compare the sensing properties of the β-Ga2O3 thin film and nanowires for UV detection. The proposed process can be optimized to a high scale production Ga2O3 nanocrystalline thin film and nanowires. By using Ag thin film as a catalyst, we can control the growth parameters to obtain either nanocrystalline thin film or nanowires.
关键词： Ga2O3,thermal oxidation,nanowires,thin film,silver catalyst,quartz
更新于2025-09-11 14:15:04