Influence Of Annealing Conditions Research Articles

Optical and Structural Properties of Europium-Doped Silicon Oxide Fabricated Using Integrated Sputtering and Chemical Vapour Deposition

Europium (Eu) doped silicon oxide (SiOx) thin films containing Eu concentrations of 0.2 to 6.4 at% were fabricated using a hybrid deposition system combining a magnetron sputtering gun serving as the doping source with electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). The influence of annealing conditions on the structural and luminescence properties was thoroughly studied. The optical properties of the films were investigated by performing variable angle spectroscopic ellipsometry (VASE) and photoluminescence (PL) measurements. The Eu-related emission was found to be highly dependent on the deposition parameters and annealing conditions. Eu2+ and Eu3+ emissions, which are attributed to blue and red light emissions, respectively, were observed. The structural properties were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, and the formation of nanoclusters was confirmed. At annealing temperatures of 900 °C and beyond, EuxSiyOz crystals were formed, and Eu ions were optically activated. As the light emissions of these thin films are in the blue and red wavelength range, they are promising candidates to be used as greenhouse covers and transparent solar cells.

Influence of annealing conditions on changes of the structure and selected properties of Al88Y7Fe5 and Al88Y6Fe6 alloys

Influence of annealing conditions on changes of the structure and selected properties of Al88Y7Fe5 and Al88Y6Fe6 alloys

Influence of annealing conditions on the performance of sputtered grown CZTS thin film solar cells

Kesterite Cu2ZnSnS4 (CZTS), with direct and tunable bandgap, high absorption coefficient, low-cost processing, earth-abundance, and non-toxicity, has become a promising absorber material for emerging thin film solar cells. The film growth, phase formation, and stoichiometry, as well as the electrical and optical properties of the sputtered grown CZTS thin films, are greatly influenced by the annealing temperature and pressure. In this work, we use a series of material characterization techniques followed by numerical simulations to determine how the annealing conditions affect the properties of CZTS thin films and the photovoltaic performance of the corresponding thin film solar cells. Sputtered grown CZTS samples were annealed at different temperatures (470 and 560 °C) and pressures (250 and 350 Torr). UV-visible spectroscopy was used to determine the optical bandgap and the absorption spectra. The experimentally determined values are then used as input parameters in the Solar Cell Capacitance Simulator-1 Dimension (SCAPS-1D) simulator tool to determine the solar cell performance. Simulation results show a maximum theoretical power conversion efficiency for the CZTS sample annealed at 560 °C and 350 Torr pressure. The results can lead to the optimization of sputtering conditions for obtaining high quality CZTS films that can yield excellent solar cell performance.

The effects of post-processing on longitudinal magnetostriction and core losses of high saturation flux density FeSiBC amorphous alloy ribbons and cores

Fe-based amorphous soft magnetic materials play an attractive role in energy saving and emission reduction due to low core losses. One of the problems is the acoustic noise resulting from magnetostriction during AC magnetization process. In this work, amorphous ribbons with a nominal composition of Fe81.5Si4B14C0.5 (at. %) were produced by planar flow casting and subjected to various postprocessing treatments. The influences of annealing conditions on the longitudinal magnetostriction, acoustic noise and core losses of the ribbons measured at low-field were studied. The effects of bending stress and epoxy impregnation and curing on medium frequency core losses of the alloy cores with different shapes were also investigated. It is shown that larger longitudinal magnetostriction of amorphous ribbons leads to higher acoustic noise emission from amorphous cores. Although the longitudinal magnetostriction was found to be reduced by applying a longitudinal magnetic field during annealing, the core loss was increased. The minimum longitudinal magnetostriction value at 1000 A/m is 7 ppm for ribbon annealed at 350 °C for 90 min. under an applied longitudinal magnetic field, while the lowest core losses at 1.4 T and 50 Hz is 0.213 W/kg for toroidal core annealed at 350 °C for 90 min. under an applied transverse magnetic field. The coupling between longitudinal magnetostriction and bending stress of amorphous ribbon results in an increase in core losses. Furthermore, extra stress was introduced after epoxy impregnation and curing, which also results in an increase in core losses. Thus, low longitudinal magnetostriction is important for stress insensitivity and soft magnetic properties.

Influence of annealing conditions on tripe-layer TiO2/Si3N4/SiO2 antireflection coatings for GaAs solar cells

In this work, TiO2/SiO2/Si3N4 triple-layer antireflection coatings (TLARC) were prepared on GaAs substrate by RF sputtering and Plasma Enhanced Chemical Vapor Deposition (PECVD). Influence of annealing conditions on the structure and optical properties of TLARC were also investigated. The structure and optical proprieties were analyzed by Grazing Incidence Angle X-ray Diffraction (GIXRD) Fourier Transform Infrared Spectroscopy (FT-IR), Atomic Force Microscopy and UV-VIS spectroscopy. The experimental results were summarized as follows: diffraction peaks of SiO2, Si3N4 and TiO2 respectively appeared in the as-deposited status, and after annealing, new diffraction peak at 25.2° corresponds to TiO2 was confirmed by checking out PDF cards; Stretching vibration of Ti=O, Si-O-Si and N-Si-N was confirmed by FT-IR spectrum; The average reflectance of the TLARC after annealing at 750 °C and holding for 5 min reached the lowest value, which was approximately 7.84 %.

Influence of annealing conditions on the photoelectrocatalytic performance of WO3 nanostructures

Nanostructured WO3 photoanodes have been synthesized by electrochemical anodization under controlled hydrodynamic conditions in acidic media in the presence of 0.05 M H2O2. Subsequently, samples have been subjected to a thermal treatment (annealing) at different temperatures (400 °C, 500 °C and 600 °C) and under different gaseous atmospheres (air, N2, Ar). The influence of these annealing conditions on the morphology, crystallinity, photoelectrochemical behavior and dopant chemistry of the different photoanodes has been investigated through Electronic Microscopy, Raman Spectroscopy, Photoelectrochemical Impedance Spectroscopy and Mott-Schottky analysis. In general, higher annealing temperatures resulted in samples with higher degrees of crystallinity, which in turn favored the transport of electron-hole pairs through the semiconducting photoanodes. Besides, an increase in annealing temperature implied higher densities of donor species within the samples structure, which can explain the observed enhancement in charge transfer. Annealing temperature was observed to have a more marked impact on the photoelectrocatalytic performance of WO3 nanostructures than the gaseous atmosphere.

Influence of Annealing Condition on Threading Dislocation Density of Ge Grown by RPCVD

The influence of annealing conditions on the crystallinity of Ge deposited on Si (001) is investigated. Ge deposited with postannealing at 800°C or 850°C, five cycles of postannealing at 750°C and 850°C and several cycles of annealing at 800°C or 850°C during the Ge growth by interrupting the deposition step (cyclic annealing) are compared. To check the threading dislocation density (TDD) of the deeper part of the Ge layer, thinning by HCl vapor phase etching (VPE) followed by Secco defect etching is performed for 5 µm thick Ge of all annealing variants. By comparing TDD of the same Ge thickness without / with HCl VPE, TDD reduction after VPE is observed for the samples with cyclic annealing process only. In the case of the cyclic annealing process, 5 µm thick Ge shows the same TDD level compared to that with five cycles of postannealing at 750°C and 850°C with lower thermal budget. A lower amount of tilted Ge planes at the interface is confirmed for the sample with cyclic annealing indicating higher crystal quality also in the deeper part of the Ge layer.

Growth and spectral-luminescence characteristics of modified BGO crystals

The optically homogeneous colorless bismuth germanate Bi4Ge3O12 (BGO) crystals (nominally pure and doped with Dy3+) were grown by Czochralski method along [1 1 1] directions. Optimal bulk crystallization rate was estimated for nominally pure crystals of 0.7 cm3/h and 0.1 cm3/h for doped materials. Influence of annealing conditions on BGO real structure and properties was shown. The colored (“reddish”) samples were obtained under special treatment. Absorption and IR luminescence spectra were measured for as-grown, annealed and doped samples. The peculiarities of colored BGO crystal and samples doped with Dy3+ ions were demonstrated.

Controllable decomposition of lanthanum oxychloride through different annealing conditions

Monolithic Lanthanum (La)-based aerogels were successfully synthesized by using the facile epoxide addition method. The as-prepared La-based aerogels were then annealed under different annealing conditions (temperature and atmosphere). The scanning electron microscopy images indicate that the as-prepared La-based aerogels are nanoporous amorphous materials with a density of ∼60 mg cm−3. Powder X-ray diffraction confirmed that lanthanum oxychloride (LaOCl) particles were formed at 500 °C in both static air and N2, and decomposed to La2O3 at ∼700 °C in static air but remained stable until ∼900 °C in N2. At 1050 °C, the LaOCl particles were completely converted to La2O3 particles in static air, while under a nitrogen atmosphere the material retained the LaOCl structure well until a conversion to the oxide. These conversions were further explored using Fourier transform infrared and photoluminescence spectroscopy. Lastly, the influence of annealing conditions on the microstructure and porosity of the La-based aerogels were also investigated.

Development of 3rd generation Medium Mn duplex steels for automotive applications

ABSTRACTThe mechanical behaviour and fracture were studied in a Fe–5Mn–2.5Al–0.2C (in wt-%) Medium Mn steel. Metallographic and magnetic measurements confirm the significant influence of the transformation kinetics of the strain-induced martensite on the mechanical properties and strain heterogeneities (Lüders and Portevin-Le Chatelier-like phenomena). An accurate study of isothermal evolutions of the microstructure, associated with atomistic calculations, complements current thermodynamic databases to quantify the nature and volume fraction of phases at different temperatures. A kinetic approach then predicts the influence of annealing conditions on the composition of retained austenite, key parameter for the martensitic transformation kinetics. This supports quantitative modelling of the influence of the intercritical annealing temperature on the ultimate tensile strength for industrial developments of these new grades.

Influence of annealing conditions on threading dislocation density in Ge deposited on Si by reduced pressure chemical vapor deposition

The influence of annealing conditions on the crystallinity of Ge deposited on Si(001) is investigated. Ge deposited with postannealing at 800 °C and 850 °C, five cycles of postannealing at 750 °C and 850 °C (temperature-swing postannealing) and several cycles of annealing at 800 °C or 850 °C during the Ge growth by interrupting the deposition step (cyclic annealing) are compared. To check the threading dislocation density (TDD) of the deeper part of the Ge, thinning by HCl vapor phase etching (VPE) followed by Secco defect etching is performed for 5 μm thick Ge of all three annealing variants. By comparing the TDD of the same Ge thickness with and without HCl VPE, TDD reduction by VPE is observed for the sample using the cyclic annealing process only. Lower TDD is observed at higher postannealing temperature. By the five cycles of temperature swinging, TDD becomes around a half compared to conventional postannealing at 850 °C. In the case of the cyclic annealing process significant improvement of TDD is observed with increasing Ge thickness. Even at a maximum temperature of 800 °C, the same or lower TDD levels were observed for higher than 2 μm thick Ge compared to that with five cycles of temperature-swing postannealing. For the sample with cyclic annealing at 800 °C, a lower Si diffusion length into Ge is also observed for the cyclic annealing process indicating a lower thermal budget. A lower amount of tilted Ge planes at the interface is confirmed showing higher crystal quality also in the deeper part of the Ge layer.

Local Mechanical Properties of Zinc-Iron Coated Steel Sheets by Depth-Sensing Indentation

Depth-sensing indentation (DSI) is used in this work to determine the change of local mechanical properties by annealing of hot-dip galvanized IF steel sheets. The influence of annealing conditions (temperature and time) on: (i) coating composition; (ii) local mechanical properties and (iii) roughness of the coating surface was quantified. Annealing of steel samples (Ti-IF steel and Ti-Nb-P-IF steel alloyed with phosphorus) was performed with different holding times (10, 60, and 300 s) by both temperatures 450 and 550 °C. The zinc in coating transformed during annealing to the intermetallic phases ZnxFey. Annealed Zn-Fe coatings, wherein the iron concentration falls towards the surface, consist of different intermetallic phases.

Au-Si plasmonic platforms: synthesis, structure and FDTD simulations.

Plasmonic platforms based on Au nanostructures have been successfully synthesized by directional solidification of a eutectic from Au and the substrate. In order to determine homogeneous shape and space distribution, the influence of annealing conditions and the initial thickness of the Au film on the nanostructures was analyzed. For the surface morphology studies, SEM and AFM measurements were performed. The structure of platforms was investigated using XRD and XPS methods. Structural investigations confirmed, that nanostructures consist of metallic Au, growing along the [111] direction. The most homogeneous seems to be the platform obtained by solidification of a 2.8 nm Au film, annealed at 550 °C for 15 min. This sample was subsequently chosen for theoretical calculations. Simulations of electromagnetic field propagation through the produced samples were performed using the finite-difference time domain (FDTD) method. The calculated absorbance, as a result of the FDTD simulation shows a quite good agreement with experimental data obtained in the UV–vis range.

Tuning the Properties of CZTS Films by Controlling the Process Parameters in Cost-Effective Non-vacuum Technique

Highly dispersive Cu2ZnSnS4 (CZTS) nanoparticles were successfully synthesized by a simple solvothermal route. A low cost, non-vacuum method was used to deposit CZTS nanoparticle ink on glass substrates by a doctor blade process followed by selenization in a tube furnace to form Cu2ZnSn (S,Se)4 (CZTSSe) layers. Different selenization conditions and particle concentrations were considered in order to improve the crystallinity and surface morphology; the annealing temperature was varied between 400°C and 550°C and the annealing time was varied between 5 min and 20 min in a selenium-nitrogen atmosphere. The influence of annealing conditions on structural, compositional, optical and electrical properties of CZTSSe thin films was studied. An improvement in the structural and surface morphology was observed with increasing of annealing temperature (up to 500°C). An enhancement in the crystallinity and surface morphology were observed for thin films annealed for 10–15 min. Absorption study revealed that the band gap energy of as-deposited CZTS thin film was approximately 1.43 eV, while for CZTSSe thin films it ranged from 1.15 eV to 1.34 eV at different annealing temperatures, and from 1.33 eV to 1.38 eV for different annealing times.

Influence of Annealing Conditions on Magnetic Properties, Magnetocaloric Effect, and Critical Parameters of Ni–Mn–Sn Ribbons

In this paper, we investigated the influence of annealing conditions on magnetic properties, magnetocaloric effect, and critical parameters of Ni50Mn50− x Sn x ( $x = 13$ , 13.5, and 14) alloy ribbons prepared by using the melt-spinning method. The ribbons were annealed at 1123 K for various times. A martensitic–austenitic (M–A) structural phase transformation was observed on both the as-quenched and annealed samples. Temperature of the M–A phase transition ( $T_{M-A}$ ) of the ribbons can be regulated in room temperature region by changing the annealing time. Maximum positive and negative magnetic entropy changes, $\vert \Delta S_{m}\vert _{\mathrm {max}}$ , larger than 3 and 1 $\text {J}\cdot \text {kg}^{-1}\cdot \text {K}^{-1}$ , respectively, were achieved on the Ni50Mn37Sn13 sample after annealing for 0.5 h. Critical parameters were determined to elucidate magnetic orders in the alloy. The obtained parameters are very close to those of the mean field theory of long-range ferromagnetic orders.

Influence of annealing conditions on elastic and dielectric properties of P(VDF‐TrFE) copolymer and its composites

In this article, we report on investigation of wave attenuation and longitudinal velocity at ultrasonic frequency in P(VDF‐TrFE) composites with fillers of conductive carbon nanotubes (CNT). Large thermal hysteresis was observed in temperature dependences of both the ultrasonic velocity and attenuation. Moreover, the temperature dependences of the ultrasonic velocity and attenuation were shown to be sensitive to thermal cycling over the ferroelectric phase transition. In our knowledge, this is the first time when the effect of annealing on the ferroelectric phase in P(VDF‐TrFE) composites is investigated by means of ultrasonic spectroscopy. Obtained results are compared with data of dielectric spectroscopy, differential scanning calorimetry, as well as thermally stimulated discharge current measurements. An analysis of the impact of CNT fillers on the dipolar charge distribution in P(VDF‐TrFE)/CNT composites was performed by means of thermally stimulated discharge current measurements. POLYM. COMPOS., 40:1609–1618, 2019. © 2018 Society of Plastics Engineers

Influence of annealing conditions on the properties of Cu(In,Ga)Se2 thin films fabricated by electrodeposition

Cu(In,Ga)Se2 (CIGS) precursor films were deposited on Mo/glass by electrodeposition, and then annealed in Se vapor. The annealing temperature ranged from 450 °C to 580 °C, and two heating rates were selected. The results showed that the crystalline quality of the CIGS films and formation of the Cu-Se compound could be strongly influenced by the selenization temperature and heating rate. Raman spectroscopy and X-ray diffraction (XRD) analysis showed that when the selenization temperature was increased from 450 °C to 550 °C, the amount of binary CuSe phase decreased and the amount of Cu2Se increased. After annealing at 580 °C, a minimum amount of Cu2−xSe compounds was obtained and the degree of CIGS film crystallinity was higher than in other samples. The relationship between the properties of the film and the heating rate was studied. XRD and Raman spectra showed a decrease in the Cu2−xSe phase with increasing heating rate. Scanning electron microscopy (SEM) and XRD showed a remarkable increase in the grain size of CIGS during rapid heating.

Effect of annealing conditions on in situ formation of Cr2O3 diffusion barrier

The previous investigation suggested the approach for an in situ formation of Cr2O3 diffusion barrier by annealing the cold-sprayed Ni coatings on 310SS. In this paper, the influences of annealing conditions on the growth kinetics of Cr2O3 and substrate microstructure were investigated. Results show that Cr2O3 formed at the selected annealing temperatures of 850, 900 and 950°C for different durations of 4, 8 and 20 h. Increasing temperature enhanced the growth kinetics of Cr2O3 and the Mn content in the oxide layer. The annealing process for the growth of Cr2O3 improves the coating adhesion compared to the as-deposited coating. However, annealing at 950°C resulted in the precipitation of chromium carbides and enhanced the element inter-diffusion across the substrate/coating interface.

Influence of annealing conditions on anodic tungsten oxide layers and their photoelectrochemical activity

The nanoporous tungsten oxide films having an amorphous structure were prepared in an electrolyte containing fluoride ions via an anodization process. The as-synthesized anodic oxide layers can be easily converted to the monoclinic WO3 phase upon annealing in air. The as-synthesized and annealed WO3 layers were investigated by using X-ray diffraction, scanning electron microscopy, and photocurrent spectroscopy. The effect of annealing temperature and annealing time on the oxide morphology, crystal structure and electrochemical properties were studied. The samples were annealed in air at the temperatures ranging from 400 to 600°C, and it was found that the original porous morphology of oxide is completely lost after annealing at 600°C. The changes in the average crystallite sizes upon annealing were confirmed by XRD measurements. The photoelectrochemical performance of the annealed WO3 layers were studied under pulsed UV illumination, and the highest photocurrents were observed at the incident light wavelength of 350nm for the sample annealed at 500°C for 2h. The band gap energy and the positions of conduction and valence band edges were determined for all studied samples.

Influence of annealing conditions on the formation of hollow Al2O3 microspheres studied by in situ ESEM

The transformation of Al microparticles into hollow and broken Al2O3 microspheres was investigated by in situ environmental scanning electron microscopy (ESEM) up to 1150°C under different heating rates and 120Pa of gas atmospheres. Slow heating rates (2°Cmin−1) resulted in a better coverage of the particles shell than with fast heating rates (20°Cmin−1) that delayed the threshold temperature at which the particles opened. Above this threshold, the amount of opened spheres increased with heating rate, with the coarser particles opening more than the small ones. It appeared that inert atmospheres (He–4%H2) increased the temperature at which the particles transformed, while air and pure oxygen tended to lower it. In contrast, the temperature interval was larger and was size-dependent when using water vapour. Irrespective of the gas atmosphere, opening of the spheres allowed molten Al to flow out from the core and aluminise the substrate while leaving behind a top coat of hollow alumina spheres.