Papers by Keyword: Annealing Temperature

Abstract: Advanced research in metal oxide-based nanotechnology has led to its broad applications, which include humidity sensors as well as electronic devices. Meanwhile, zinc oxide (ZnO)/tin oxide (SnO₂) composite nanostructure has established a presence in many electronic devices, and their performance can be further enhanced by electrospraying at high annealing temperatures. This paper explores how annealing temperature influences the structural properties and performance of ZnO/SnO₂ nanostructures in AZO-based humidity sensors. The ZnO/SnO₂ nanostructures were fabricated on AZO glass utilising electrospraying and then subjected to annealing at various temperatures: 100°C, 200°C, 300°C, 400°C as well as 500°C. The structural characteristics of the synthesized films were analysed utilising Field-Emission Scanning Electron Microscopy (FESEM) as well as X-ray Diffraction (XRD). Additionally, the humidity sensing performance of the films was evaluated based on their response time, sensitivity as well as recovery time. Following the results, a higher annealing temperature resulted in smaller crystallites and smaller diameters within the 71.6–91.9 nm range. Besides, the XRD patterns demonstrate a shift in the (002) peaks towards a higher angle value with incremental annealing temperature. In terms of the humidity sensing performance, the sensitivity level increased with increasing annealing temperature, while the recovery period and response time were reduced. In summary, the annealing temperature significantly influenced the performance of the ZnO/SnO₂ composite nanostructures, which recorded the best sensitivity of 173.10, 234 seconds response time, and 80 seconds recovery time after annealing at 500°C.

Abstract: Thin films of tungsten oxide were deposited on glass substrates by the radio frequency (RF) reactive sputtering from a high purity tungsten metal target (99.9%) with a diameter of 10 cm. The reactive sputtering was carried out in an argon-oxygen gas mixture containing 20% of O₂ and 80% of Ar. The used RF power is 200 W while fixing the deposition time at 120 min. Finally, the prepared films were annealed at different temperatures (350 °C, 400 °C, 450 °C, 500°C and 550 °C) for 1 hour under air and under vacuum. X-ray diffractograms showed that the deposited thin films crystallized in Hexagonal/Monoclinic WO₃ phase. It was found that the crystallite size varies with the annealing temperature and the lattice parameters is a= 7.3064Å, b = 7.5292Å, c = 7.6875Å and a=b= 7.3242Å, c= 7.6624 Å, for h-WO₃ and m-WO₃ structures, respectively. Scanning Electron Microscopy (SEM), Raman spectra confirmed the formation of WO₃ thin films. In addition, optical transmittance data revealed that the optical bandgap of the films decreases with increasing the annealing temperature. Electrical measurements revealed that annealing in air results in more resistive samples, which should be taken into account in future investigations, especially as buffer layers for efficient photovoltaic solar cells. Keywords: Vacuum, Tungsten oxide, Raman spectroscopy, RF Sputtering method, RF Power, Annealing temperature.

Abstract: Since Fe-based amorphous alloys are widely used in magnetic separators, sensors and other fields, it is of practical significance to carry out research on amorphous strips used in this field.The effects of annealing temperature on the soft magnetic properties of Fe_70.43Nb_10.77Si_15.77Cu_2.34B_0.69 amorphous nanostrips with 25 μm and 28 μm thickness prepared by the single roll cold method were investigated at 20 and 300K.Five specimens were annealed at472.12K, 672.12K, 772.12K, 822.12Kand 872.12K, respectively, and their microstructure and magnetic properties were tested viametallographic microscopy, X-ray diffraction, and vibrating specimen magnetometer. At cryogenic temperatureof 20K, specimens annealed at 672,12K exhibited the best magnetic properties, including the coercive forceof8.1265A/m, saturation magnetic induction intensity of1.4351T,and its residual value of 0.2462T. The comparative analysis of experimental results obtained strongly indicates that the soft magnetic properties of the amorphous alloy are significantly improved by the particular annealing treatment.

Abstract: The annealing temperature is a key parameter for the mechanical properties and microstructure control of the 2195 Al-Li alloy sheet in the annealing process. In the present study, the effect of annealing temperature on the microstructure of 2195 Al-Li alloy sheet was investigated using a general mechanical testing machine, scanning electron microscope (SEM), transmission electron microscope (TEM), and backscattered electron microscope (EBSD). It was found that the optimized annealing temperature for 2195Al-Li alloy sheet of H112 state is 400°C, the alloy sheet shows the satisfactory mechanical properties. In addition, with the increase of annealing temperature, the δ' phase, the θ' phase and the T1 phase are formed in the alloy sheet, which leads to the strength of the alloy increase. Furthermore, the annealing temperature obviously affect the texture component and intensity during annealing treatment process.

Abstract: The annealing process of an improved Q420 cold drawn tube was studied by using different annealing temperatures (430°C, 450°C, 470°C, 490°C and 510°C) with a same annealing holding time (3h). The effect of different annealing temperatures on the mechanical properties, microstructure and fracture features of the cold drawn tube was studied by means of tensile test, microstructure observation and scanning electron microscopy analysis. The results show that, annealing temperature has great influence on the strength and plasticity of the cold drawn tube. When the annealing temperature increased to 450°C, banded microstructure was mitigated and the pearlite is relatively dispersed. The tensile fracture morphology under the annealing temperature of 450°C has more dimples and deeper bremsstrahlung than other annealing temperatures. The best annealing process of the cold drawn tube was 450°C×3h. Under this annealing process, the cold drawn tube with good strength and toughness can be obtained.

Abstract: The DC reactive magnetron sputtering method was employed to deposit Titanium Chromium Nitride (TiCrN) thin film on silicon (100) substrates. The coatings were annealed at different temperature from 700°C to 1000°C with increase step of 100 °C in air for 2 h. The crystal structure, surface morphologies, microstructure and chemical compositions were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). The x-ray patterns confirmed the TiO₂ rutile structure with strong preferred orientation of (101) plane was appeared from 700°C. The crystallinity of film increased with the annealing temperatures. The lattice constant (a and c) were in the range of 4.565 – 4.607 Å and 2.946 – 2.956 Å. The void between grain boundaries was confirmed by FE-SEM micrograph. The cross-sectional analysis revealed that the porous structure with enhancement of thickness from 1.64 - 1.95 μm were obtained as increase annealing temperatures. The EDX results indicated that the O content increase from 0 – 60.67 At% whereas the Ti, Cr, and N contents were decreased from 43.26 - 22.40 At%, 20.65 – 2.57 At% and 51.19 – 14.36 At% through the annealing temperatures.

Abstract: Photosupercapacitor is an integrated device for harvesting and storing solar energy into electrical energy. Photosupercapacitor is constructed by solar cell and supercapacitor. In the solar cell with DSSC type, one of the influential variables is photoanode performance. The photoanode with ZnO layer plays a role in light absorption, charge mobility, and electrical properties, which are influenced by crystal structure and nanoscale morphology. One of nanoscale morphology of ZnO that widely used is nanorods. This work is focussed to investigate the effect of annealing temperature on seed layer ZnO to growth nanorods shape in photoanode of photosupercapacitor and its performance. The seed layer ZnO nanoparticle was deposited onto FTO substrate by a screen printing method. The ZnO nanorod was grown by dippin FTO/ZnO in solution (Zinc nitrate, HMT, and DI water) under 100 °C. The photosupercapacitor was constructed by DSSC and ZnO symmetric supercapacitor which integrated by using aluminum foil substrate. The annealing temperature on ZnO nanoparticles affected on increasing crystal size of ZnO seed. All of the samples show ZnO wurtzite phase with the highest peak located on the hkl plane (101), but ZnO nanorod growth to hkl plane (100). The DSSC part efficiency produced around 0.874%. The resulting efficiency of photosupercapacitor is around 0.549%. The annealing temperature causes the value of specific capacitance to decrease, because of decreasing DSSC performance.

Abstract: This study is conducted to investigate the effect of different annealing temperature on the growth of Silver doped Titanium Dioxide (AgTiO₂) nanocrystalline thin films.AgTiO₂ nanocrystalline thin films on silicon wafer have been prepared by sol–gel spin coating. The thin films were characterized for surface morphology and phase analysis by Scanning Electron Microscope (SEM) and X-ray diffraction (XRD. The films prepared by titanium tetraisopropoxide (TTIP) as the precursor under pH of 3.5 ± 0.5 and with annealing temperature of 300, 400, 500 and 600°C for 2h soaking time. X-Ray diffraction shows that only Ag/TiO₂ thin film annealed at 600°C have anatase TiO₂ phase. From SEM micrograph, there are cracks and pulled out thin film from the substrate, which were gradually minimize as the annealing temperature increase.

Abstract: SnO₂ thin films were prepared on glass substrates by sol-gel spin coating method using stannous chloride dihydrate and ethyl alcohol absolute as raw materials at annealing temperature 450-550 °C. The crystal phase was measured by X-ray diffraction (XRD) and showed tetragonal rutile structure with a preferential orientation of (110). Atomic force microscope (AFM) and Scanning Electron Microscope (SEM) images revealed the homogeneous grains distribution, and SEM images showed the obvious rectangular objects corresponding to tetragonal structure. Optical properties were observed by the transmittance in ultraviolet-visible (UV-Vis) region and optical energy gap, which revealed the transmittance over 75% and energy gap between 3.84 eV and 3.89 eV. Finally, I-V characteristics were tested to research electrical properties, and found the gradual non-linear property and the increase of resistance.

Abstract: Dye sensitized solar cell (DSSC) is a well-known photovoltaic device that is used for low power application. One of the main components for DSSC is semiconductor material photoanode which will provide the pathway for electron transportation and thus determine the energy conversion efficiency of the DSSC. The most commonly used material for the semiconductor photoanode is titanium dioxide (TiO₂)_. TiO₂ is a semiconductor material with wide bandgap material that is existed in three crystalline phase; rutile, anatase and brookite. This paper emphasizes the best annealing temperature for commercialized TiO₂, 98% anatase powder where the temperature varies from 300 oC – 600 oC. Through this research, the best annealing temperature for anatase TiO₂ photoanode is at 420 °C (0.094%) with the crystallite size of 18.76 nm and particle size of 19 nm that is favorable for the dye attached and thus enhances the energy conversion efficiency of the DSSC.