Tensile behavior of post-irradiation annealed Cu–Ni alloy

The present paper investigates the tensile properties of post-irradiation annealed Cu–Ni alloy. The specimens were irradiated with a 15 MeV electron beam at room temperature and the post-irradiation annealing (PIA) of the specimens was carried out under vacuum at 450 °C for 15–120 min. The yield stress (YS), ultimate tensile stress (UTS), percentage elongation, stress relaxation rate and activation volume of both as-irradiated and post-irradiation annealed specimens were examined at room temperature using a universal testing machine. The results show that PIA of the specimen at 450 °C for 15 min decreases its YS and UTS, whereas the percentage elongation is increased. The changes in the tensile parameters become more pronounced with increases in annealing time. Effects of PIA on the stress relaxation rate and activation volume indicate that the relaxation rate of post-irradiation annealed specimens increases, and the activation volume decreases, with an increase in annealing time.     

Interfacial reactions of rf-sputtered TiNi thin films on (100) silicon with a SiN diffusion barrier

Silicon nitride (SiN) with a 50?nm thickness on Si(100) as a thermal barrier was obtained by plasma-enhanced chemical vapour deposition (PECVD). TiNi thin films were rf sputtered on a SiN/Si substrate and then annealed at 400–700°C for 30?min. Their interfacial reactions were studied using transmission electron microscopy, X-ray diffraction and Auger electron spectroscopy analyses. Experimental results show that the thickness of reaction layer in TiNi/SiN/Si specimens is clearly reduced, compared with that in TiNi/Si specimens under the same annealing conditions. The significant effect of the SiN layer as a diffusion barrier in TiNi/SiN/Si can be recognized. N and Si atoms diffuse from the SiN layer to react with TiNi films at 500°C and 600°C respectively. The TiN_{1 ? x} phase is formed in specimens annealed at 500°C, and mixed Ti₂Ni₃Si and Ti₄Ni₂O compounds are found at 600°C. In the specimen annealed at 700°C, the reaction layer has sublayers in the sequence TiNi/Ti₄Ni₂O/Ti₂Ni₃Si/TiN_{1 ? x} /SiN/Si. The SiN thermal barrier obtained by PECVD caused quite different diffusion species to cross the interfaces between TiNi/SiN/Si and TiNi/Si specimens during the annealing.     

Effect of annealing on structural and optical properties of diamond-like nanocomposite thin films

The annealing effect on structural and optical properties of the Diamond-like Nanocomposite (DLN) thin film deposited on glass substrate by Plasma Assisted Chemical Vapor Deposition (PACVD) method has been investigated. The films were annealed at temperature ranging from 300 to 600 °C, with 100 °C interval for 9 minutes by rapid thermal process (RTP) under vacuum. The structural changes of the annealed films have been studied using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Scanning Electron Microscope (SEM), and optical parameters have been determined using transmittance and reflectance spectra in UV-UIS-NIR range. The result shows that the refractive index increases gradually from 1.79 to 2.84 with annealing temperature due to out-diffusion of H by breaking Si–H and C–H bond leads to Si–C bond, i.e. more cross linking structure. In higher temperature range, graphitization also enhanced the refractive index. However, the optical band gap at up to 400 °C initially increases from 3.05 to 3.20 eV and then decreases due to graphitization. The film has a great potential to be used as anti-reflection coating (ARC) on silicon-based solar cell.     

Effect of annealing on the opto-electronic properties of Cu0.9In1.0Se2.0 films

The influence of annealing on the structure and opto-electronic properties of Cu_0.9In_1.0Se_2.0 films prepared by solution growth technique has been studied. The films annealed at 500–520°C in air, vacuum (10^?4 torr), In-vapour and Se-vapour show polycrystalline chalcopyrite structure with orientation perpendicular to the (220) plane. Films annealed in Se-vapour at 500°C for 30 min have maximum grain size (560 Å), minimum optical energy gap, maximum absorption coefficient, lowest resistivity, maximum photosensitivity and thus are suitable for photovoltaic applications. Annealing in In-vapour or in vacuum changesp-type CuInSe₂ inton-type which possibly arises due to the increase in Se vacancies.     

Study of structural and electrical properties of thin NiO<Subscript>x</Subscript> films prepared by ion beam sputtering of Ni and subsequent thermo-oxidation

Nickel oxide thin films were prepared by thermal annealing of thin Ni films (thickness ca 47?nm) deposited by ion beam sputtering. The thermal annealing was performed at 350 °C and 400 °C with elected time (1–7 hours) in a quartz furnace opened to air. During annealing the samples underwent structural changes, as well as changes of their electrical properties. The structural properties (surface morphology and occurrence of crystalline phases) were analyzed by the AFM and XRD methods, O and Ni depth concentration profiles by the NRA method, and electrical properties (sheet resistance) by the van der Pauw 4-point technique. The sheet resistance (R _S ) of the as-deposited sample was found to be 12.03 Ω/□; after open air thermal annealing at 350 °C for 1 h the value was found to be almost the same, 11.67 Ω/□. After 2 h of annealing, however, a sharp increase in the sheet resistance (R _S = 1.46 MΩ/□) was observed. At this stage the deposit formed largely oxidized Ni layer with a distinct polycrystalline structure. The sharp increase of sheet resistance was ascribed to the oxidation of the Ni layer, leaving only a smaller amount of isolated Ni particles unoxidized. Almost complete oxidation was found after 7 h of annealing at 350 °C. At 400 °C was almost complete oxidation recorded already after 1 h of annealing.     

Effect of annealing time on properties of spinel LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> high-voltage lithium-ion battery electrode materials prepared by co-precipitation method

In this wok, a series of LiNi_0.5Mn_1.5O₄ (LNMO) samples with an octahedral shape entirely composed of (111) crystal planes were prepared by calcining the mixture of the precursor Ni_0.25Mn_0.75(OH)₂ and LiOH·H₂O at 800 °C for 15 h in air, followed by annealing them at 600 °C for different dwelling times. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and several electrochemical technologies were used to investigate the effect of annealing time on properties of the LNMO samples. XRD analysis indicates that the lattice parameters of the LNMO samples show a decreasing trend with increasing of annealing time, and the impurity peaks become less apparent for the sample annealed for 6 h and almost disappear for the samples annealed for 9 and 24 h. SEM results show that the annealing time has no obvious influence on the morphologies of the LNMO samples. Electrochemical measurements show that the electrochemical performances (capacity, cycle life, and rate capability) of the samples annealed for 6, 9, and 24 h are better than those of the unannealed sample, and the sample annealed for 9 h shows the best electrochemical properties among them due to its superior electrochemical kinetics of Li⁺ insertion/desertion.     

Annealing Effects on the Structural and Optical Properties of Thermally Deposited Tin Antimony Sulfide Thin Films

We report the deposition and characterization of tin antimony sulfide thin films on a soda glass substrate by a thermal evaporation technique. The thin films were annealed in argon gas at 150, 175, and 300 °C inside glass ampoules. The structural and optical properties of the deposited and annealed films are investigated. X-ray diffraction (XRD) patterns show that the films are polycrystalline in structure. Photoconductivity plot revealed good response in the NIR and visible regions, while the films show no transmittance below 700 nm. The absorption coefficient was of the order of 10⁶ cm^?1. Optical band gaps were also evaluated and a decrease in band gap was observed due to annealing. Hot point probe technique was employed for type of conductivity.     

Surface morphology study of recrystallization dynamics of amorphous ZnO layers prepared on different substrates

Amorphous oxides-based devices are exposed, during fabrication, to different processing conditions affecting their properties. Zinc oxide is a prospective candidate for transparent amorphous oxides, but its structure is changing under the influence of temperature. We investigated surface recrystallization of amorphous zinc oxide layers deposited onto fused silica, sapphire and Si substrates by pulsed laser deposition. The prepared three series of layers had highly nonequilibrium phase structures. Using atomic force microscopy and scanning electron microscopy, the effect was studied of subsequent annealing at 200, 400, 600, 800 °C for 60 min upon the surface structural properties of the layers. The following parameters were analyzed: average roughness, RMS roughness and size of formed grains on selected places with 1 × 1 μm² area. Surface structural analysis revealed that annealing led to recrystallization of the prepared layers and roughening of the structural features on the surface. With increasing annealing temperature, the calculated parameters were increasing. The average surface roughness of zinc oxide layers annealed at 800 °C is three times higher than that of the layers annealed at lower temperatures for all substrates used. The process dynamics of thermally caused recrystallization of the layers was different for each of the substrates used.     

Solid State Reaction of Ruthenium with 6H-SiC Under Vacuum Annealing and the Impact on the Electrical Performance of its Schottky Contact for High Temperature Operating SiC-Based Diodes

Thin films and Schottky diodes dots of ruthenium (Ru) on bulk-grown n-type-6-hexagonal-silicon carbide (6H-SiC) were annealed isochronally in a vacuum furnace at temperatures ranging from 500–1,000 °C. Rutherford backscattering spectroscopy analysis of the thin films showed formation of ruthenium silicide (Ru₂Si₃) at 800 °C, while diffusion of Ru into 6H-SiC commenced at 800 °C. Raman analysis of the thin films annealed at 1,000 °C showed clear D and G carbon peaks which was evidence of formation of graphite. At this annealing temperature, the Schottky contact was observed to convert to an ohmic contact, as evidenced by the linearity of current–voltage characteristic, thereby, rendering the diode unusable. The transformation from Schottky contact to ohmic contact is attributed to graphite formation at the interface.     

Luminescence lifetimes in quartz: dependence on annealing temperature prior to beta irradiation

It is well known that the thermal history of a quartz sample influences the optically stimulated luminescence sensitivity of the quartz. It is found that the optically stimulated luminescence lifetime, determined from time resolved spectra obtained with pulsed stimulation, also depends on past thermal treatment. For samples at 20°C during stimulation, the lifetime depends on beta dose and on duration of preheating at 220°C prior to stimulation for quartz annealed at 600°C and above, but is independent of these factors for quartz annealed at 500°C and below. For stimulation at higher temperatures, the lifetime becomes shorter if the sample is held at temperatures above 125°C during stimulation, in a manner consistent with thermal quenching. A single exponential decay is all that is required to fit the time resolved spectra for un-annealed quartz regardless of the temperature during stimulation (20–175°C), or to fit the time resolved spectra from all samples held at 20°C during stimulation, regardless of annealing temperature (20–1000°C). An additional shorter lifetime is found for some combinations of annealing temperature and temperature during stimulation. The results are discussed in terms of a model previously used to explain thermal sensitisation. The luminescence lifetime data are best explained by the presence of two principal luminescence centres, their relative importance depending on the annealing temperature, with a third centre involved for limited combinations of annealing temperature and temperature during stimulation.     

Structural and optical characterization of Sb-doped CuInS2 thin films grown by vacuum evaporation method

Structural, electrical and optical properties of Sb-doped CuInS₂ thin films grown by single source thermal evaporation method were studied. The films were annealed from 100 to 500 °C in air after the evaporation. The X-ray diffraction spectra indicated that polycrystalline CuInS₂ films were successfully obtained by annealing above 200 °C. This temperature was lower than that of non-doped CuInS₂ films. Furthermore, We found that the Sb-doped CuInS₂ thin films became close to stoichiometry in comparison with non-doped CuInS₂ thin films. The Sb-doped samples annealed above 200 °C has bandgap energy of 1.43–1.50 eV.     

Effect of annealing time on the structural and ferromagnetic properties of the GaMnN thin films

GaMnN thin films were deposited on a sapphire (0001) substrate by using laser assisted molecular beam epitaxy. Subsequently, the samples were annealed in the ammonia ambience at 1000 °C for different time lengths. The crystalline quality was improved gradually, and the room temperature ferromagnetism of our samples becomes stronger with the increase of the annealing time within 25 min. The X-ray photoelectron spectra analysis confirmed that the Mn³⁺ concentration in the GaMnN films increased after annealing. The stronger ferromagnetism was observed in the sample with the higher Mn³⁺ concentration. However, too long annealing time, such as 35 min, will lead to the degradation of the crystalline quality and the decrease of Mn³⁺ concentration, which results in the weakened ferromagnetism. The optimal annealing time is 25 min at 1000 °C in our experiments. Finally, the origin of the room temperature ferromagnetism in our samples was discussed preliminarily.     

Effect of thermal annealing on optical properties of CR-39 polymeric track detector

The samples of CR-39 polymer (TASTRAK, Bristol, England) were annealled thermally at various temperatures ranging from 100°C to 180°C for 1 hour, in air. FTIR spectroscopy reveals the structural degradation of CR-39 polymer due to thermal annealing above its glass transition temperature. Optical band gap of pristine and thermally annealed samples has been determined using UV-Visible absorption spectra. It has been observed that the optical band gap decreases continuously as a result of annealing.      

Annealing properties of a pre-irradiation annealed plastic track detector

The studies regarding the annealing properties of a pre-irradiation annealed Makrofol N track detector showed that under “moderate annealing conditions”, the maximum etched track length l_max, can be increased. The increase becomes maximum at pre- and post-irradiation annealing temperatures of 80°C and 60°C respectively.     

EPR and Magnetization Studies of Polymer-Derived Fe-Doped SiCN Nanoceramics Annealed at Various Temperatures: Blocking Temperature,Superparamagnetism and Size Distributions

X-band EPR spectra on SiCN ceramics, doped with Fe(III) ions, annealed at 800 °C, 1000 °C, 1100 °C, 1285 °C, and 1400 °C have been simulated to understand better their magnetic properties, accompanied by new magnetization measurements in the temperature range of 5–400 K for zero-field cooling (ZFC) and field cooling (FC) at 100C. The EPR spectra reveal the presence of several kinds of Fe-containing nanoparticles with different magnetic properties. The maxima of the temperature variation of ZFC magnetization were exploited to estimate (i) the blocking temperature, which decreased with annealing temperature of the samples and (ii) the distribution of the size of Fe-containing nanoparticles in the various samples, which was found to become more uniform with increasing annealing temperature, implying that more homogenous magnetic SiCN/Fe composites can be fabricated by annealing at even higher temperatures than 1400 °C to be used as sensors. The hysteresis curves showed different behaviors above (superparamagnetic), below (ferromagnetic), and about (butterfly shape) the respective average blocking temperatures, 〈T_B〉. An analysis of the coercive field dependence upon temperature reveals that it follows Stoner–Wohlfarth model for the SiCN/Fe samples annealed above 1100 °C, from which the blocking temperatures was also deduced.     

Role of substrate temperature on structure and magnetization of Cr-implanted GaN thin film

Chromium ions implantation was performed into metal–organic chemical vapor deposition grown GaN thin film of thickness about 2 µm at 5 × 10¹⁶ cm^?2 fluence. Implantation was performed at various substrate temperatures (RT, 250, 350 °C). Rapid thermal annealing was employed at 900 °C to remove implantation-induced damages as well as for activation of dopant. Structural study was performed by Rutherford backscattering and channeling spectrometry and high-resolution X-ray diffraction. To confirm magnetic properties at room temperature, hysteresis loops were obtained using alternating gradient magneto-meter. Well-defined hysteresis loops were achieved at 300 K in implanted and annealed samples. Temperature-dependent magnetization indicated magnetic moment at 5 K and retain up to 380 K.     

Influence of Annealing Treatment on Structural,Optical, Electric,and Thermoelectric Properties of MBE-Grown ZnO

In this paper, we have reported the influence of annealing treatment on structural, optical, electrical, and thermoelectric properties of MBE-grown ZnO on Si substrate. After growth, a set of as grown ZnO was annealed in oxygen environment at 500–800°C and another set was annealed in different environments (vacuum, oxygen, zinc, and vacuum + zinc) at 600°C for one hour in a programmable furnace. X-ray diffraction (XRD) results demonstrated that all annealed samples exhibited a major diffraction peak related to (002) plane. The full width at half maximum (FWHM) of this plane decreased and crystalline size increased for oxygen annealed sample and it increased when samples were annealed in zinc, vacuum, and successively annealed in vacuum and zinc. Further, photoluminescence spectrum revealed that the intensity of band edge emission increased and defect emission decreased as annealing temperature (oxygen environment) increased while it decreased for rest of annealing ambient. It is suspected that annealing in oxygen environment causes compensation of the oxygen vacancies by the incoming oxygen flux, while annealing in zinc and vacuum generates more oxygen vacancies. Hall and Seebeck measurements are also consistent with these arguments.     

Annealing embrittlement of Fe78Si9B13 (METGLAS-2605S2)

The ductile to brittle transition that occurs in amorphous Fe₇₈Si₉B₁₃ (METGLAS-2605S2) has been investigated using mechanical measurements over the temperature range 250–370 °C. The fracture toughness values, K _Ic , have been determined for a range of annealing times (5–30 min) and cooling rates of 15–45 °C/min. A pronounced ductile to brittle transition is observed around 310(10) °C although no obvious structural changes are evident as indicated by x-ray diffraction. Comparison of transmission and back-scattered conversion electron ⁵⁷Fe Mössbauer spectra for the bulk as-received ribbon in the ductile state ( $K_{Ic}=52~{\rm MPa} \cdot \sqrt{m}$ ) and the ribbon annealed to the brittle state ( $K_{Ic}\sim10~{\rm MPa} \cdot \sqrt{m}$ ) indicates magnetic texture effects in both the bulk and on the surface of these amorphous ribbons, related to the magnetostriction resulting from the quenched-in stress during the ribbon production process, and the ensuing stress-relief upon annealing.     

Some Luminescence Properties of the Blue Emission Band of Muscovite

Egyptian muscovite has the main thermoluminescence emission band in the blue region (450–490 nm). The natural band has thermoluminescence peaks at 240, 260 and 270°C. The initial rise method shows that these peaks have thermal activation energies of 1.32, 1.41 and 1.38 eV, respectively. The laboratory-induced peaks at 100, 140, 160 and 240°C have activation energies of 0.55, 0.64, 0.94, and 1.32, respectively. For fired muscovite when exposed to 1 kGy of γ-radiation, followed by annealing at 500°C for 0.5h and cooling in air, the sensitivity increased to be ~36 the original value. The effect of different cooling rates after the heat treatment was also studied. The phase transitions of the crystal are the main reasons for the changes in the thermoluminescence properties.     

Effects of Annealing on Microstructure and Optical Properties of TiO2 Sculptured Thin Films

The evolution of microstructure and optical properties of TiO2 sculptured thin films under thermal annealing is reported. XRD, field emission SEM, UV-Vis-NIR spectra are employed to characterize the microstructural and optical properties. It is found that the optimum annealing temperature for linear birefringence is 500℃. The maximum of transmission difference for linear birefringence is up to 18%, which is more than twice of that in as-deposited thin films. In addition, the sample annealed at 500℃ has a minimum of column angle about 12℃. The competitive process between the microstructural and optical properties is discussed in detail. Post-annealing is a useful method to improve the linear birefringence in sculptured thin films for practical applications.