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This work reports a detailed study on the low-temperature synthesis of highly conductive transparent Al-doped ZnO films using magnetron sputtering with the support of an inductively coupled plasma (ICP) source. It is seen that the ICP source is quite useful to provide significant ionization and excitation reactions conducive to the film growth in the magnetron plasmas. The effect of different plasma parameters on the film properties is investigated in detail. Data reveal that tailoring of vacancies of oxygen and extrinsic dopants (Al0 and Al3+) and plasma chemistry in high electron density discharges could provide simultaneous enrichment in the carriers' mobility and concentration. A plausible mechanism involving the correlation between the carrier mobility and the electron-hole interaction is realized for degenerately doped wide bandgap semiconductors. [ABSTRACT FROM AUTHOR]

The safety of antiperspirants has been a subject of intense debate, with conflicting perspectives and research findings. This study aimed to contribute to the discussion by investigating the distribution of aluminum chloride (AlCl3), a common ingredient in antiperspirants, within the sweat glands. We enrolled a total of 10 patients seeking surgery for bromhidrosis in our study. Before surgery, we instructed the study participants to apply a specially formulated AlCl 3 staining antiper- spirant to their underarms using a surgical pen with ink that resists easy removal. We excised the apocrine glands, fragmented them finely, and examined them microscopically. We did not detect any stained aluminum compounds. These results are consistent with previous research, which suggests that aluminum compounds do not enter the apocrine glands. Consequently, concerns regarding the potential absorption of aluminum into the human body appear to be unfounded, particularly regarding cancer risks such as breast cancer. [ABSTRACT FROM AUTHOR]

A quantitative method for the analysis of aluminum in tobacco products was developed, validated and applied to select samples. Samples were prepared using standard microwave digestion of tobacco from various products. Detection and quantification utilized sector field inductively coupled plasma-mass spectrometry. Method applicability to analyze aluminum in a range of tobacco products was demonstrated with quantitative analyses of smokeless tobacco products, cigarette tobacco, little cigar tobacco and roll-your-own/pipe tobacco. Though these products represent a convenience sampling, we observed that smokeless tobacco products, as a category, had the lowest average aluminum concentrations. Roll-your-own or pipe tobacco and little cigar tobacco had higher median and ranges of aluminum concentrations than cigarette and smokeless tobacco samples. [ABSTRACT FROM AUTHOR]

The microstructure, texture, and mechanical properties of the Al/Ni/Cu composite during various accumulative roll bonding (ARB) cycles were studied using optical microscopy, scanning electron microscopy, x-ray diffraction, shear punch test, and hardness test. In addition, ImageJ software and Rietveld software were used in order to study microstructure and dislocation density variations, respectively. It was found that Ni and Cu layers were fractured and distributed in the Al matrix due to differences in their mechanical properties. Fracture and distribution of Cu and Ni particles after cycle five led to the alteration of the composite structure from a layered to a particle-reinforced structure. ARB process leads to the formation of strong orientation along the β-fiber and also to pronounced copper and dillamore components in both Al and Cu phases. Furthermore, the shear yield stress and ultimate shear strength of the composite increased as the ARB process advanced; however, shear elongation presented a non-uniform variation. Investigation of the fracture surfaces revealed that the mechanical properties of the composite are affected not only by the strain hardening of the Cu layer, but also by the structural change in the composite during the initial ARB cycles. During the last stages of the process, however, changes in mechanical properties were mostly governed by reinforcement particles serving as strain concentration zones and the strain hardening of the Al matrix. [ABSTRACT FROM AUTHOR]

The influence of elemental cerium addition on the cooling curve parameters and microstructure of hypereutectic Al-23Si alloy was investigated in this work. The cooling rate of the treated and untreated alloy samples was varied by solidifying the melt against chills of different materials in a stainless-steel tube. The cooling curve was recorded and nucleation temperatures of various phases in the alloy were measured. The results show that the chilling improves the effectiveness of the modifier. The two main phases of the alloy, primary silicon and eutectic silicon, were nucleated at temperatures of about 661.2 and 571.6 °C, respectively. The addition of Ce to slowly cooled alloys resulted in an increase in undercooling temperature of both the phases, with a decrease in its nucleation temperature, whereas the same additions increased the nucleation temperatures in chilled alloys. Based on the thermal analysis results, a relation between thermal analysis parameter (ΔTG) and silicon particle size of the alloy was proposed. [ABSTRACT FROM AUTHOR]

A new aluminum ion fluorescent probe (4-(diethylamino)-2-hydroxybenzylidene)isoquinoline-1-carbohydrazide (HL 1 ) has been conveniently synthesized and characterized. HL 1 exhibited a highly selective and pronounced enhancement for Al 3+ in the fluorescence emission over other common cations by forming a 2:1 complex, with a recognition mechanism based on excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT). The strong fluorescent emission can be observed even at ppm level concentration of the probe in the presence of Al 3+ with 41 fold intensity enhancement at 545 nm. HL 1 displays good linear relationship with Al 3+ in the low concentration and the limit of detection is 8.08 × 10 −8  mol/L. Similar molecules with different substituents on salicylaldehyde phenyl ring were synthesized for studying the structure-activity relationship. Density-functional theory (DFT) calculations are in agreement with the proposed mechanism. It is confirmed that HL 1 could be used to detect Al 3+ ions in real sample by fluorescence spectrometry and Al 3+ ions in cells by bioimaging. [ABSTRACT FROM AUTHOR]

In the current study, Al2O3-TiN composites were successfully fabricated with various particle sizes (10, 20, 30 and 50 μm) and concentrations (5, 10, 15, and 20 vol %) via a novel ball milling + Ti reactive sintering process. By applying the reactive sintering, Ti powders will transform into TiN particles, which act as mechanical reinforcements and electrical conductors in the Al2O3- matrix. The ball milling process alters the Ti powder morphology from a low-aspect-ratio sphere into a high-aspect-ratio disc, which reduces the electrical percolation threshold value from 29% to 15% in the current setup. However, such a threshold value is insensitive to the particle size. Meanwhile, the Ti particle size has a significant influence on the material's mechanical properties. A small particle size results in less porosity and hence higher flexural strength of the composite. [ABSTRACT FROM AUTHOR]

We report a novel approach for metal organic vapor phase epitaxy of (Al)GaN heterostructures on Si substrates. An approximately 90-100 nm thick SiC buffer layer is synthesized using the reaction between Si substrate and CO gas. High-resolution transmission electron microscopy reveals sharp crystalline interfaces with epitaxial relationship between SiC/Si and AlN/SiC layers. Optimization of SiC morphology and AlN seed layer thickness facilitates the growth of GaN layers free of pits (v-defects). It is also found that Si doping eliminates these defects in the case of growth on SiC templates with non-optimized surface morphology. Thus, synthesis of thin SiC buffer layer is suggested as a solution for the interface problems at the initial stage of III-N on Si epitaxy. [ABSTRACT FROM AUTHOR]

In this study, the effects of processing parameters on the microstructure of Al-Cu-Fe-Cr quasicrystalline (QC) coatings fabricated by selective laser melting (SLM) are investigated. A qualitative analysis on the XRD patterns indicates that the phase composition for the SLM processed coating mainly consisted of Al-Cu-Fe-Cr quasicrystals and α-Al (CuFeCr) solid solution, and with increasing laser energy input or coating thickness, the volume fraction of QC i-Al 91 Fe 4 Cr 5 reduced and those of QC d-Al 65 Cu 20 Fe 10 Cr 5 and crystalline θ-Al 2 Cu increased. The formation of cracks during the coating building procedure from single layer to multilayers is also discussed. For the coatings with the same layer number, the pores and balling particles diminish as laser power increases, due to the growth of melting degree. At the early stage of fabrication, with increment of layer number (or coating thickness), pores and balling particles decrease considerably because the molten pool solidified more “slowly”. However, after the layer number increases continuously from 10 to 20, the porosity no longer decreases, and some big size pores, microcracks and fractures appear, especially for the sample obtained at lower laser power. A wavy-like pattern composed chiefly of Al and QC phases, is formed at the interfacial region between substrate and coating due to Marangoni effect. [ABSTRACT FROM AUTHOR]

This study investigated the effect of an Al2O3 passivation layer on the stability of radio-frequency magnetron cosputtered aluminum-indium-zinc oxide (Al-IZO) thin-film transistors (TFTs) under positive bias stress, positive bias illumination stress, negative bias illumination stress, and constant current stress. In current devices, threshold-voltage (Vth) instability is dominated by the photogenerated hole/electron trapping at a back-channel surface and/or interface between an insulator and a channel, and the deep defects (subgap states) located near the valence band can easily cause a subgap photoexcitation, resulting in a large Vth shift. In this study, experimental results show that Al2O3-passivated Al-IZO TFTs exhibit stable electrical behaviors under each stress condition (ΔVth<1.7 V), whereas the unpassivated Al-IZO TFTs exhibit obvious shifts in threshold voltage (ΔVth<10.50 V). In this study, the authors demonstrated that Al2O3 could be an effective passivation layer to suppress O2 absorption/desorption on the Al-IZO back-channel and decrease photo-excitation on Al-IZO films. [ABSTRACT FROM AUTHOR]

Highly reactive integrated material systems have recently gained attention, as they promise a feasible tool for heterogeneous integration of micro electromechanical systems. As integrated energy sources they can be used to join heterogeneous materials without applying too much thermal stress to the whole device. An alternative approach is proposed, comprising a single layer of a reactive nanocomposite made of intermixed metal nanoparticles, instead of multilayer systems. In this study the development of the reactive nanocomposite from choice of materials through processing steps, handling and application methods are described. Eventually the results of the experiments upon the reactivity of the nanocomposites and the feasibility for bonding applications are presented. Analysis of the composites was performed by phase-analysis using x-ray diffraction and reaction propagation analysis by high-speed imaging. Composition of products was found to vary with initial particle sizes. Beside of other phases, the dominant phase was intermetallic NiAl. [ABSTRACT FROM AUTHOR]

The possibilities of quantitative secondary ion mass spectrometry (SIMS) depth profiling of Al in AlxGa1 − xN/AlN/GaN transistor heterostructures are shown. Using a series of test structures for a TOF.SIMS-5 time-of-flight mass spectrometer, we obtained a refined linear calibration dependence of the secondary-ion yield on the composition ×, namely, Y(CsAl+)/Y(CsGa+) = K × x/(1 − x), with a high linear correlation coefficient, Rl = 0.9996, which permits quantitative SIMS analysis of relatively thick AlGaN barrier layers. The method of profile reconstruction with allowance for the main artifacts of ion sputtering has been first applied for the analysis of GaN/AlGaN/AlN/GaN high electron mobility transistor structure. This method permits to perform quantitative analysis of the thickness and composition of a nanometer-thin AlN sublayer and to estimate the measurement error. For the structure being studied, the AlN sublayer is 1.2 ± 0.2 nm thick. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

III-Bi compounds have been extensively studied in recent years because of their wide applications in optoelectronic devices. Despite the wealth of theoretical works, optical properties of first two members of this family, namely BBi and AlBi, are not completely investigated in the literature. Thus, we have studied electronic and optical properties of these compounds using the density functional theory (DFT) based on full potential linearized augmented plane wave method (FP-LAPW) as implemented in the WIEN2k. We have used the Yukawa Screened-PBE0 (YS-PBE0) hybrid function to calculate structural, electronic and optical properties of BBi and AlBi for the first time in the literature. Our structural and electronic results are compared with other available theoretical studies. Finally, optical parameters of both BBi and AlBi compounds have been investigated by means of our obtained electronic results. [ABSTRACT FROM AUTHOR]

Synthesis and characterization (gas phase, solution, and solid-state) of a series of four-, five- and six-fold coordinated heteroaryl-alkenolato aluminum complexes were performed to demonstrate the delicate interplay of structural and chemical influences of ligands in the design of new precursors for chemical vapor deposition. We are investigating the properties of heteroaryl alkenols as ON chelating ligands [where ON is 3,3,3-trifluoro(pyridin-2-yl)propen-2-ol (H-PyTFP), 3,3,3-trifluoro(1,3-benzimidazol-2-yl)propen-2-ol (H-BITFP), 3,3,3-trifluoro(dimethyl-1,3-oxazol-2-yl)propen-2-ol (H-DMOTFP), 3,3,3-trifluoro(1,3-benzoxazol-2-yl)propen-2-ol (H-BOTFP), 3,3,3-trifluoro(1,3-benzthiazol-2-yl)propen-2-ol (H-BTTFP), and 3,3,3-trifluoro(dimethyl-1,3-thiazol-2-yl)propen-2-ol (H-DMTTFP)] to prepare volatile and air-stable compounds. All three methyl groups in highly reactive AlMe3 could be replaced by H-PyTFP, H-BITFP, H-DMOTFP, and H-BOTFP yielding octahedral complexes of the type Al(ON)3; under similar conditions H-BTTFP and H-DMTTFP produced heteroleptic MeAl(ON)2 compounds with five-fold coordinated aluminum centers. Various attempts to obtain tris-alkenolato derivatives by choosing higher temperatures and prolonged reaction times were not successful. The reaction of H-PyTFP with [Al(OtBu)3]2 produced the dimeric heteroleptic [Al(PyTFP)(OtBu)2]2 complex with Al atoms present in both octahedral (Oh) and tetrahedral (Td) coordination in a single molecular unit. The introduction of the chelating ligand H-PyTFP in the dimeric framework of [Al(OtBu)3]2 enhanced the stability against hydrolyses significantly. The tendency of Al(III) centers to preferably coordinate in Td or Oh environment was elucidated by hydrolysis studies of monomeric Al(PyTFP)3, Al(BOTFP)3, and MeAl(BTTFP)2 that produced hydroxo-bridged dimers to retain the octahedral environment for Al atoms. Surprisingly, hydrolysis of monomeric MeAl(DMTTFP)2 yielded an oxo-bridged dimer with two five-fold coordinated aluminum centers. The structural features of all new complexes were investigated in solution, vapor, and solid state by multinuclear NMR spectroscopy, EI-MS spectrometry, and single-crystal X-ray diffraction analyses, respectively. [ABSTRACT FROM AUTHOR]

Triisobutylaluminum reacts with silica yielding three different Al sites according to high-field aluminum-27 NMR and first principle calculations: a quadruply grafted dimeric surface species and two incorporated Al(O)x species (x = 4 or 5). This result is in stark contrast to the bis-grafted species that forms during Et3Al silica grafting. Thus the isobutyl ligands, which render R3Al monomeric, lead to greater reactivity towards the silica surface. [ABSTRACT FROM AUTHOR]

This letter reports an extensive analysis of the charge capture transients induced by OFF-state bias in double heterostructure AlGaN/GaN MIS- high electron mobility transistor grown on silicon substrate. The exposure to OFF-state bias induces a significant increase in the ON-resistance (R \(_{\mathrm {{on}}}\) ) of the devices. Thanks to time-resolved on-the-fly analysis of the trapping kinetics, we demonstrate the following relevant results: 1) R \(_{\mathrm {{on}}}\) -increase is temperature- and field-dependent, hence can significantly limit the dynamic performance of the devices at relatively high-voltage and high temperature (100 °C–140 °C) operative conditions; 2) the comparison between OFF-state and back-gating stress indicates that the major contribution to the R \(_{\mathrm {{on}}}\) -increase is due to the trapping of electrons in the buffer, and not at the surface; 3) the observed exponential kinetics suggests the involvement of point-defects, featuring thermally activated capture cross section; and 4) trapping-rate is correlated with buffer vertical leakage-current and is almost independent to gate-drain length. [ABSTRACT FROM AUTHOR]

A compact Lecher Line apparatus (21 cm in length) has been constructed. Standing waves can be demonstrated when different terminations are added to the line and these allow the frequency of the radiation to be determined. By having Phase Detection permittivity values of liquid or granular materials can be determined. As an example, the permittivity of granular sugar was found to be 1.9 (±0.2). [ABSTRACT FROM AUTHOR]