Humidity sensing properties of spray deposited Fe doped TiO2 thin film

In the present work, ferrite (Fe) doped TiO2 thin films with different volume percentage (vol%) were synthesized using a spray pyrolysis technique. The effect of Fe doping on structural properties such as crystallite size, texture coefficient, microstrain, dislocation densities etc. were evaluated from the X ray diffratometry (XRD) data. XRD data revealed a polycrystalline anatase TiO2 phase for sample synthesized up to 2 vol% and mixed anatase and rutile crystalline phase for sample synthesized at 4 vol% Fe doped TiO2. The crystalline size was observed to decrease with increase in Fe dopant vol% and also other structural parameters changes with Fe dopant percentage. In the present work, electrical resistance was observed to decrease with a rise in Fe dopant vol% and temperature of the sample. Thermal properties like temperature coefficient of resistance and activation energy also showed strong correlation with Fe dopant vol%. Humidity sensing properties of the synthesized sample altered with a change in Fe dopant vol%. In the present paper, maximum sensitivity of about 88.7% for the sample synthesized with 2 vol% Fe doped TiO2 and also the lowest response and recovery time of about 52 and 3 s were reported for the same sample.

Structural characterisation of copper oxide by X-ray diffraction

In this work, the study of the structural characterization of copper oxide by the X-ray diffraction technique is presented. To obtain layers of copper oxide, sputtering and thermal oxidation techniques were combined. The average crystal size was calculated for the sputtered copper samples. For the copper oxide films obtained by thermal oxidation, both the crystal size and the texture coefficient were calculated. The crystalline quality was poor for layers obtained by sputtering. Thermal oxidation carried out on these films transformed its structure to the copper oxide phase known as cupric oxide.

Impact of Annealing Time on Structural Evolution of Pure and Dy3+-Doped CeO2 Nanopowder, Rietveld Refinement and Optical Behavior

This work reports about annealing time effect on structural and optical properties of pure and Dy[Formula: see text]-doped CeO2 nanocrystallites. The nanopowders with an average grain size 13–15[Formula: see text]nm are successfully synthesized via a conducive and neoteric Pechini-type sol–gel technique. Surface morphology, composition, band gap and photoluminescence properties of the prepared samples are examined by multifarious characterization techniques like Rietveld refinement, FESEM, HRTEM, FTIR, UV–Vis spectroscopy and PL. The effects of annealing time on structural parameters including lattice parameter, bond distance, bond angle, strain, crystallite size and texture coefficient are computed for all prepared samples which are further ensured by Rietveld refinement. In absorption spectra, blue shift in the band gap of as-prepared samples has been observed due to well-known quantum size effect, however, red shift is noticed in further annealed samples. PL emission peaks are observed in violet, blue and green regions that are devoted to various defect levels and color centers such as F, F[Formula: see text], F[Formula: see text], etc. It is suggested that defects like oxygen vacancies play vital role in tailoring the band gap of prepared samples and therefore enhance its utility in photonics and oxygen storage appliances.

New Ti–35Nb–7Zr–5Ta Alloy Manufacturing by Electron Beam Melting for Medical Application Followed by High Current Pulsed Electron Beam Treatment

High-current pulsed electron-beam (PEB) treatment was applied as a surface finishing procedure for Ti–35Nb–7Zr–5Ta (TNZT) alloy produced by electron beam melting (EBM). According to the XRD results the TNZT alloy samples before and after the PEB treatment have shown mainly the single body-centered cubic (bcc) β-phase microstructures. The crystallite size, dislocation density, and microstrain remain unchanged after the PEB treatment. The investigation of the texture coefficient at the different grazing angle revealed the evolution of the crystallite orientations at the re-melted zone formed at the top of the bulk samples after the PEB treatment. The top-view SEM micrographs of the TNZT samples treated by PEB exhibited the bcc β-phase grains with an average size of ~85 μm. TEM analysis of as-manufactured TNZT alloy revealed the presence of the equiaxed β-grains with the fine dispersion of nanocrystalline α and NbTi4 phases together with β-Ti twins. Meanwhile, the β phase regions free of α phase precipitation are observed in the microstructure after the PEB irradiation. Nanoindentation tests revealed that the surface mechanical properties of the melted zone were slightly improved. However, the elastic modulus and microhardness in the heat-affected zone and the deeper regions of the sample were not changed after the treatment. Moreover, the TNZT alloy in the bulk region manufactured by EBM displayed no significant change in the corrosion resistance after the PEB treatment. Hence, it can be concluded that the PEB irradiation is a viable approach to improve the surface topography of EBM-manufactured TNZT alloy, while the most important mechanical parameters remain unchanged.

Structural Origin of Magnetotransport Properties in APCVD Deposited Single and Bi-Layer Tin Oxide Thin Films

Transparent conducting oxides (TCO) with high electrical conductivity and at the same time high transparency in the visible spectrum are an important class of materials widely used in many devices requiring a transparent contact such as light-emitting diodes, solar cells and display screens. Since the improvement of electrical conductivity usually leads to degradation of optical transparency, a fine-tuning sample preparation process and a better understanding of the correlation between structural and transport properties is necessary for optimizing the properties of TCO for use in such devices. Here we report a structural and magnetotransport study of tin oxide (SnO2), a well-known and commonly used TCO, prepared by a simple and relatively cheap Atmospheric Pressure Chemical Vapour Deposition (APCVD) method in the form of thin films deposited on soda-lime glass substrates. The thin films were deposited at two different temperatures (which were previously found to be close to optimum for our setup), 590 °C and 610 °C, and with (doped) or without (undoped) the addition of fluorine dopants. Scanning Electron Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GIXRD) revealed the presence of inhomogeneity in the samples, on a bigger scale in form of grains (80–200 nm), and on a smaller scale in form of crystallites (10–25 nm). Charge carrier density and mobility extracted from DC resistivity and Hall effect measurements were in the ranges 1–3 × 1020 cm−3 and 10–20 cm2/Vs, which are typical values for SnO2 films, and show a negligible temperature dependence from room temperature down to -269 °C. Such behaviour is ascribed to grain boundary scattering, with the interior of the grains degenerately doped (i.e., the Fermi level is situated well above the conduction band minimum) and with negligible electrostatic barriers at the grain boundaries (due to high dopant concentration). The observed difference for factor 2 in mobility among the thin-film SnO2 samples most likely arises due to the difference in the preferred orientation of crystallites (texture coefficient).

Effects of alkaline zinc bath formulations on electrochemical corrosion behavior of electrogalvanized coatings

The effects of alkaline non-cyanide zinc plating bath formulation on the plating characteristics and deposit properties are investigated. Scanning electron microscope and X-ray diffractometer are used to study the surface morphology and texture of the zinc deposits respectively. Uniform and compact coatings with a dominant (110) texture are obtained for all of the bath formulations. Nevertheless, significant differences in surface morphology and relative preferences for the (110) and (100) planes were found to result from the concentrations of zinc and sodium hydroxide in the bath. Electrochemical impedance spectroscopy and potentiodynamic polarization scan were employed to evaluate the corrosion resistance. The coatings with a moderate Zn (8-11 g/L) and controlled NaOH (120 g/L) contents show good corrosion resistance, with the corrosion current and corrosion rate being the lowest at 8 g/L of Zn and 120 g/L of NaOH. The ratio of texture coefficient, morphology, and compressive residual stress from different bath composition contribute to the corrosion resistant property. The findings from this work should provide useful information of electrogalvanized zinc coatings with enhanced corrosion resistance.

A comparative study of the method of Williamson Hall and the pattern of cadmium oxide nanoparticles for X-rays

X-ray difraction (XRD) is an effective non-destructive instrument used in the determination and analysis of amorphous and crystalline materials. Three basic elements are the X-ray diffractometers: the X-ray tube, a retention of samples and an X-ray detector. In many industries such as diodes, transistors, detectors, solar and photovoltaic cells, cadmium oxide CdO nanoparticles are used. For this analysis, CdO nanoparticles are semi-conductors (type) and band-gaps of 2.5 eV and 1.98 eV in direct and indirect bands using cadmium oxide. Several temperatures, effects and parameters such as texture coefficient (TC), dislocation density(μ), special area (SSA), and micro strain were measured and determined (S). The peaks of the analysis were the extension of the nano structure, crystal size and grid pressure of the CdO and were measured using the Size Train Plot of Williamson-Hall (SSP). The composition of the particle is the cubic fluorite and spatial group Fm-3m (225). In the peaks resulting from the calcination process, strain enlargement was observed. Accordingly, the above procedure determined all physical parameters as a result of the diffraction effects.

Using Information Content to Select Keypoints for UAV Image Matching

Image matching is one of the most important tasks in Unmanned Arial Vehicles (UAV) photogrammetry applications. The number and distribution of extracted keypoints play an essential role in the reliability and accuracy of image matching and orientation results. Conventional detectors generally produce too many redundant keypoints. In this paper, we study the effect of applying various information content criteria to keypoint selection tasks. For this reason, the quality measures of entropy, spatial saliency and texture coefficient are used to select keypoints extracted using SIFT, SURF, MSER and BRISK operators. Experiments are conducted using several synthetic and real UAV image pairs. Results show that the keypoint selection methods perform differently based on the applied detector and scene type, but in most cases, the precision of the matching results is improved by an average of 15%. In general, it can be said that applying proper keypoint selection techniques can improve the accuracy and efficiency of UAV image matching and orientation results. In addition to the evaluation, a new hybrid keypoint selection is proposed that combines all of the information content criteria discussed in this paper. This new screening method was also compared with those of SIFT, which showed 22% to 40% improvement for the bundle adjustment of UAV images.

Comparison of Optical, Electrical, and Surface Characteristics of InGaN Thin Films at Non-Flow and Small Nitrogen Flow Cases

InGaN films in the non-flow and a small flow of nitrogen cases were fabricated by the RFMS (Radio Frequency Magnetron Sputter) method to compare crucial physical characteristics of its material. From the XRD analysis, application of small nitrogen flow in InGaN thin film growth has been observed to result in changes in the crystal size, texture coefficient, and crystal structure parameters of the film. AFM results showed both films obtained have tightly packed granular, and almost homogeneous, and Nano-structural properties, but they are different in roughness, as increased by applying small nitrogen flow. Optical conductance peaks of the material in non-flow and small flow case were 1.3957 x 1010 and 1.1496 x 1010 (S/m), showed a decrement in optical conductance by small nitrogen flow. In the same manner, electrical conductance peaks of the material in non-flow and small flow case were 5.2512 x 1012 and 5.2236 x 1012 (S), showed a decrement in electrical conductance by small nitrogen flow. In addition, the electrical conductivity of the InGaN material has been obtained at higher than the optical conductivity value of the InGaN material in both cases. Also, it was noticed that direct allowed optical band gap energy non-flow and small flow cases were 2.4701 and 2.5225 eV, displayed increased by applied small nitrogen flow. Essentially, many noteworthy physical properties such as crystalline size, texture coefficient, optical/electrical conductivity, the surface roughness of the films have been compared and studied for the non-flow and a small flow of nitrogen cases.

Influence of Strong and Weak Alkaline Medium on Microstructural and Morphological Investigation of Surfactant Based Synthesis of CdO Nanorods

A noval microwave irradiated wet chemical method was adopted to prepare cadmium oxide nanostructures by using sodium dodecyl benzenesulphonate (SDBS) as surfactant in presence of strong and weak 0.1M alkaline medium (NaOH and NH4OH). The X-ray diffraction measurement shows that the particle is crystallized in the cubic phase, average grain size of the samples are found to be in the range 54 nm for NH4OH reagant and 60 nm for NaOH reagent. The XRD pattern value based lattice constant, dislocation density, X-ray density, specific surface area, microstrain–Williamson Hall and texture coefficient have been calculated. The surface functionality of the samples were analysed by using fourier transform infrared spectroscopy. The ultra visble transmittance and K-M plot analysed from the diffuse reflection spectra and photoluminescence spectra also been calculated. The morphological changes of cadmium oxide nanostructures with strong and weak 0.1M alkaline medium are clearly recored through transmission electron miscroscopy. The reaction mechanism confirms that the experiment carried out in presence of 0.1M NaOH shows rod shaped nanostructures through four step mechanism such as hydaration, intermediate formation, metal hydroxide formation and the formation of metal oxide.