Papers by Keyword: Annealing Temperature

Abstract: The effects of annealing temperature on microstructure, mechanical properties, formability, and texture evolution were analyzed in the article. The microstructure of the steel obtained through different annealing processes were investigated by means of transmission electron microscopy; The micro texture of steel was measured by using electron back scattering diffraction analysis; The relationship between Cu precipitates and matrix was analyzed by using the selected area diffraction technology. The results show that when annealing temperature was 700 ~ 850 °C, the yield strength and tensile strength first decreased slightly and then increased, while the elongation accordingly first increased then decreased slightly. The best mechanical property and formability were obtained at 800 °C. Cu precipitates reduced with the increase of annealing temperature and it accorded with K - S relationship with matrix. The grains near the {111} < 112 > orientation grew up selectively. The higher the temperature, the more the γ fiber texture content. But at higher temperature (850 °C), γ texture was damaged and the content was reduced.

Abstract: In the present work, the precipitation method was applied to prepare zinc oxide nanoparticles in the presence of zinc nitrate and potassium hydroxide as precursor solutions. The influence of annealing temperature on the properties such as structural and morphological of zinc oxide nanoparticles were performed by X-ray diffraction technique, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy. The effects of annealing temperature on the crystallite size of zinc oxide nanoparticles have investigated. The XRD results represented that the zinc oxide nanoparticles exhibits high crystallinity of hexagonal wurtzite crystal structure. The average crystallite size of nanoparticles increased from 18 to 31 nm when the annealing temperature had increased. The morphology images show that the nanoparticles in this work were spherical in shape. Raman and FT-IR spectra confirm that the quality of Zn-O vibrational mode is stronger at higher annealing temperature.

Abstract: ZnO thin films is a kind of very potential semiconductor materials, due to their excellent chemical, electrical and optical properties. The effects of annealing temperature and coating layers on properties of ZnO thin films prepared by sol-gel immerse technique is studied in this work. The structure properties and optical properties were investigated by XRD, SEM and UV-Vis spectrophotometry respectively. It is found that the thin films were composed of better hexagonal wurtzite crystals with the c-axis preferred orientation by thermal annealing 550°C. With coating layers increasing from 2 layers to 8 layers, the intensity for all diffraction peaks were increased gradually, and the crystallite size of ZnO thin films is slightly increased. The transmittance of prepared thin films is over 80% in the visible-near IR region from 460 nm - 800 nm.

Abstract: In this research, NiO/ZnO heterojunction thin films were fabricated on a ITO substrate by a sol–gel technique. The as-prepared thin films were annealed at various temperatures. The effect of annealing temperature on structural, surface morphology and electrical properties of thin films was investigated by XRD, FESEM and I-V characteristic measurement. The XRD results revealed that NiO/ZnO thin film was polycrystalline and exhibited better crystallization when annealing temperature was increased. The current-voltage curve of all sample exhibited the diode behaviour.

Abstract: In order to investigate the effect of annealing temperature on oxygen clusters’ evolution in silicon wafer during low temperature annealing, a phase-field model and it’s algorithm were established, and the changes of the oxygen clusters’ structure, amount (concentration) and sizes were simulated at different annealing temperature. The results show that when the temperature varies from 923 to 1023K, the oxygen clusters with reasonable amount and average size can be gained; when the temperature is too higher or lower, the suitable oxygen clusters cannot be found; it is verified that the established model and its algorithm have credible thermodynamics and experimental basis.

Abstract: ZnMn₂O₄ films were fabricated on p-Si substrate by magnetron sputtering. The effects of annealing temperature on microstructure, resistance switching properties and endurance characteristics of ZnMn₂O₄ films were investigated. The ZnMn₂O₄ films with a structure of Ag/ZnMn₂O₄/p-Si exhibit bipolar resistive switching behavior. The results indicated that the annealing temperature has not changed its spinel structure, the bipolar resistance behavior and endurance characteristics, but the grain become more and more large, arranged closed and distributed evenly with the increase of annealing temperature from 450°C to 750°C. The ZnMn₂O₄ films annealed at 600°C have the biggest R_HRS/R_LRS ratio, the lowest V_ON and V_OFF. The R_HRS/R_LRS ratios of all specimens maintain at about 10³ after successive 1000 switching cycles, which indicated that the Ag/ZnMn₂O₄/p-Si device has better endurance characteristics.

Abstract: In this work, seeded porous silicon (PSi) was used as a substrate in the growth of ZnO nanostructures. PSi was prepared by electrochemical etching method. ZnO thin films as seeded were deposited via sol-gel spin coating method. ZnO nanostructures were grown on seeded PSi using hydrothermal immersion method. In order to study the effect of post-heat treatment on the substrate, post annealing temperature were varied in the range of 300 to 700 °C. The FESEM results shows ZnO thin film composed of nanoparticles were distributed over the PSi surface. Based on AFM characterization, the smoothest surface was produced at post annealing temperature of 500 °C. There are two different peaks appeared in PL characterization. The peak in near-UV range is belonging to ZnO thin films while a broad peak in visible range can be attributed to ZnO defects and PSi surface. In addition, FESEM, XRD and PL were used to characterize the ZnO nanostructures. The FESEM results revealed ZnO nano-flower were successfully grown on seeded PSi. Hexagonal wurtzite of ZnO with dominated by the plane (100), (002), and (101) was found by XRD characterization. Two different peaks in UV range and visible range can be attributed to ZnO nano-flower and various defects of ZnO, respectively.

Abstract: ZnO nanorods (NRs) arrays were synthesized by chemical solution deposition (CSD) method on commercial glass substrate with ZnO thin film act as seed layer prepared by sol-gel spin coating. The effect of annealing temperature of 150°C, 250°C and 500°C, respectively, on the structural growth was investigated. The observation reveals the structural improvement as the annealing temperature increased. The influence of gadolinium doping to ZnO NRs arrays was explored upon the structural and optical features. The FESEM imaging along with XRD, AFM and UV-Vis analysis were conducted to dissect the information gained by performing a study case on various gadolinium doping content in the range of 1 at. % to 4 at. %. Based on the results, the correlation between the doping content were drawn in details in this paper.

Abstract: The most important thing in preparing thin films ceramic material such lead titanate, PbTiO₃ is the behavioral of microstructural changes due to the applying heat treatment during crystallization process. In general, the imperfection of PbTiO₃ surface morphology such as porosity, grain boundaries, existence of microcrack films, films out-diffusion and others are caused by this factor, heat transfer element and found very interesting to be discussed towards next electrical characterization. However, the present study only focuses on the surface morphology of PbTiO₃ thin films that observed by both field emissions scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The details of measurement for observation will be explained later. The preparation of PbTiO₃ thin films were done trough simple sol-gel spin coating method deposited on ITO coated glass substrate.

Abstract: Performance of lead titanate, (PbTiO₃) thin films have been successfully investigated on microstructural properties, I-V characteristic, dielectric properties, and ferroelectric properties. PbTiO₃ offers variety of application as transducer, ferroelectric random access memory, transistor, high performance capacitor, sensor, and many more due to its ferroelectric behavior. Preparation of the films are often discussed in order to improve the structural properties, like existence of grain boundaries, particle uniformity, presents of microcrack films, porosities, and many more. Yet, researchers still prepare PbTiO₃ thin films at high crystallization temperature, certainly above than 600 ̊C to obtain single crystal perovskite structure that would be the reason to gain high spontaneous polarization behavior. Although this will results to high dielectric constant value, the chances that leads to high leakage current is a major failure in device performance. Thus, preparation the thin films at low annealing temperature quite an essential study which is more preferable deposited on low-cost soda lime glass. The study focuses on low annealing temperature of PbTiO₃ thin films through sol-gel spin coating method and undergo for dielectric and I-V measurements.