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PHYTOSYNTHESIS OF SILVER NANOPARTICLES USING E. CAMALDULENSIS LEAF EXTRACT AND THEIR CHARACTERIZATION
摘要： Herein, we report a simple green synthesis of silver nanoparticles (Ag NPs) by the reduction of aqueous silver salt solution using leaf broth of Eucalyptus camaldulensis. The profile of synthesized silver nanoparticles was evaluated by using UV-visible spectrophotometer, X-ray diffractometer, atomic force microscope, energy-dispersive X-ray spectroscope and scanning electron microscope. Surface plasmon resonance peak of silver nanoparticles appeared at 425 nm in UV-vis spectra of silver nanoparticles. XRD studies clearly confirmed the crystalline nature of the synthesized nanoparticles. The EDX analysis disclosed the arranged inorganic composition of the synthesized Ag NPs. Atomic force microscopy investigation revealed 3D surface profile of nanoparticles. From the SEM images, the silver nanoparticles were found to be more or less spherical with an average diameter range of 110-250 nanometers.
关键词： E. camaldulensis,SEM,AFM,UV-visible spectrophotometry,XRD,Ag NPs
更新于2025-09-10 09:29:36
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Synthesis, characterisation, and antimicrobial activity of ZnO-based nanocomposites
摘要： In this study, ZnO-based nanocomposites including ZnO/CuO (S1), ZnO/MnO (S2), and ZnO/MnO/CuO (S3), were synthesised. S1, S2, and S3 were characterised through Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Also, the antimicrobial property of the samples was examined against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli through the colony forming count method. FTIR analysis confirmed the presence of Zn–O, Mn–O, and Cu–O in the samples. The crystalline structure of the sample was analysed by XRD. The surface morphology of the prepared compounds was studied with SEM images. EDS technique was employed for ensuring the presence of Zn, Mn, and Cu elements in the samples. The results clearly showed S1, S2, and S3 had high-antimicrobial activity especially for S3.
关键词： SEM,EDS,FTIR,XRD,antimicrobial activity,ZnO-based nanocomposites
更新于2025-09-10 09:29:36
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Crystal Morphology and Phase Transformation of LiAlO <sub/>2</sub> : Combined Experimental and First-Principles Studies
摘要： Layered α-LiAlO2 matrix often suffers from detrimental structural and morphological changes during its lifetime, especially under H2 containing fuel inlet environments of molten carbonate fuel cell systems. However, the underlying mechanism of this phase and morphological transformations has rarely been explored. In this study, transmission electron microscopy (TEM) techniques were used to determine the changes in structure and morphology of LiAlO2 samples lifted by a focused ion beam (FIB). In accordance with X-ray diffraction (XRD) analysis, TEM images show that under H-rich conditions the rhombohedral α-LiAlO2 transforms to tetragonal γ-LiAlO2 phase with the appearance of the (101) terminated octahedral shaped γ-LiAlO2 crystallites. We further support, and plausibly rationalize, the observed transformations using density functional theory (DFT) calculation. The DFT computed surface energies of γ-LiAlO2 reveal that the {101} surface becomes the lowest energy surface upon H-adsorption, thus leading to formation of observed octahedral geometry. Contrary to stabilization of γ-LiAlO2 surfaces upon H passivation, DFT revealed H-adsorption on α-LiAlO2 surfaces to be energetically unfavorable. This contrasting behavior of α-LiAlO2 and γ-LiAlO2 under H-rich environments could be a potential driving force for the observed α-LiAlO2 to γ-LiAlO2 phase transformation.
关键词： morphology,phase transformation,TEM,DFT,LiAlO2,XRD
更新于2025-09-10 09:29:36
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Dislocations behavior in highly mismatched III-Sb growth and their impact on the fabrication of <i>top-down</i> n?+?InAs/p?+?GaSb nanowire tunneling devices
摘要： We study in this work the growth and fabrication of top-down highly doped n + InAs(Si)/p + GaSb(Si) Esaki tunneling diodes on (001) GaAs substrates. A careful investigation on the highly mismatched GaSb/GaAs growth is first conducted by means of Reflection High-Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and X-Ray Diffraction (XRD) analyses. These results are expected to pave the way to methods for III-Sb buffer layer’s integration with low threading dislocation (TD) densities. A comparison between AFM, XRD, defect revealing by chemical etching and transmission electron microscopy (TEM) is then presented to calculate the precise TD density and its influence on the device structure. In the last part, we report on first operating sub-30 nm III-V vertical NW tunneling devices on (001) commercial GaAs substrates.
关键词： III-Sb growth,AFM,dislocations,TEM,nanowire tunneling devices,XRD,RHEED,GaAs substrates
更新于2025-09-10 09:29:36
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Analysis of the inhomogeneous barrier and phase composition of W/4H-SiC Schottky contacts formed at different annealing temperatures
摘要： The electrical characteristics of W/4H-SiC Schottky contacts formed at different annealing temperatures have been measured by using current–voltage–temperatures (I–V –T ) and capacitance–voltage–temperatures (C–V –T ) techniques in the temperature range of 25 ?C–175 ?C. The testing temperature dependence of the barrier height (BH) and ideality factor (n) indicates the presence of inhomogeneous barrier. Tung’s model has been applied to evaluate the degree of inhomogeneity, and it is found that the 400 ?C annealed sample has the lowest T0 of 44.6 K among all the Schottky contacts. The barrier height obtained from C–V –T measurement is independent of the testing temperature, which suggests a uniform BH. The x-ray diffraction (XRD) analysis shows that there are two kinds of space groups of W when it is deposited or annealed at lower temperature ((cid:54) 500 ?C). The phase of W2C appears in the sample annealed at 600 ?C, which results in the low BH and the high T0. The 500 ?C annealed sample has the highest BH at all testing temperatures, indicating an optimal annealing temperature for the W/4H-SiC Schottky recti?er for high-temperature application.
关键词： inhomogeneity barrier,SiC,Schottky contact,x-ray diffraction (XRD)
更新于2025-09-09 09:28:46
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Enhanced dielectric properties of BaTiO3 ceramics with cerium doping, manganese doping and Ce-Mn co-doping
摘要： Ba1?xCexTi1?yMnyO3 (where x and y varies from 0.00 to 0.03) ceramic samples are synthesized by conventional solid state reaction technique. The samples are sintered at 1473 K for 4 h. The grain size is observed to increase with increasing dopant and co-dopant concentration. The X-ray diffraction confirmed the cubic phase of these BaTiO3-based ceramics with a small amount of secondary phase. The current density shows a nearly linear relationship with voltage, and the AC resistivity of the samples is observed to decrease with increasing frequency and doping concentration. The dielectric constant and dielectric loss were observed to decrease with frequency in the lower frequency range (0.2–10 kHz), but remained almost the same at the high-frequency region (>10 kHz). Though Ce-doped samples shows better dielectric properties than Mn-doped samples, the Ce-Mn co-doped samples, having improved their dielectric properties, can be used to fabricate different optoelectric devices.
关键词： resistivity,SEM,solid state reaction,dielectric properties,XRD,grain size
更新于2025-09-09 09:28:46
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In-doped Sb nanowires grown by MOCVD for high speed phase change memories
摘要： We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400 μW) and fast switching capabilities with respect to standard Ge-Sb-Te based devices. In particular, reversible set and reset switches by voltage pulses as short as 25 ns were demonstrated. The obtained results are useful for understanding the effects of downscaling in PCM devices and for the exploration of innovative PCM architectures and materials.
关键词： In-Sb,Nanowires,Phase change memories,XRD,TEM,MOCVD
更新于2025-09-09 09:28:46
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Ion irradiation effects on Sb-rich GaSb films
摘要： Here we show the formation of amorphous, non-stoichiometric GaSb films by magnetron sputtering and the ion irradiation effects on the films. GaSb films in the 20–300 nm thickness range were deposited by magnetron sputtering on SiO2/Si substrates at room temperature and subsequently irradiated with 17 MeV Au+7 ions at different fluences. Structural, compositional, and morphological characterizations were performed by means of x-ray diffraction, Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, scanning electron microscopy and x-ray absorption fine structure analyses. We could verify that, throughout the above-mentioned thickness range, films were amorphous, with excess Sb to the ratio 1:2 (Ga:Sb). The initially compact films attained a foam-like structure after irradiation, with significant swelling that is dependent on the initial film thickness: the thicker the film, the more it swelled. The excess Sb attained different oxidation states depending on film thickness and this influenced the final density of the films, thus influencing the swelling. The local atomic structure around Ga atoms was also investigated, revealing a decrease in Ga–Sb scattering contribution with increasing irradiation fluence, at the same time as the increase in Ga–O scattering for irradiation fluence above 1×1014 at/cm2 (inclusive).
关键词： XPS,XAFS,RBS,GaSb films,ion irradiation,XRD,magnetron sputtering
更新于2025-09-09 09:28:46
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[Lecture Notes in Electrical Engineering] Engineering Vibration, Communication and Information Processing Volume 478 (ICoEVCI 2018, India) || A Facile Synthesis of Graphene Oxide (GO) and Reduced Graphene Oxide (RGO) by Electrochemical Exfoliation of Battery Electrode
摘要： Graphene is a two-dimensional allotrope of carbon, in which carbon atoms are arranged in a hexagonal structure. All carbon atoms in graphene are sp2 hybridized due to which three atoms are bonded to neighboring atoms and one electron is unbounded. Here, we have demonstrated a facile and low-cost technique to synthesize the graphene oxide and reduced graphene oxide from readily available battery graphite by means of an electrochemical method using liquid electrolyte. The graphite in the battery electrode has been expanded using acid for effective exfoliation. This is used to increase the interlayer spacing of graphite causes the van der Waals forces to cease. Graphene oxide and reduced graphene oxide (reduction using ascorbic acid) have been synthesized using this technique. The optical microscope image has shown few layer ?akes and X-ray powder diffraction (XRD) demonstrated the reduction of oxygen content. The proposed setup is cheap and environmentally benign in nature.
关键词： Graphene oxide,Optical microscope,Electrochemical technique,Reduced graphene oxide,XRD
更新于2025-09-09 09:28:46
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Current transport and capacitance-voltage characteristics of Sb2Se3/n-Si heterojunction diode prepared by electron beam evaporation
摘要： The Sb2Se3 thin film was successfully deposited on the n-Si substrate using an electron beam evaporated technique. The structural investigation was done by means of X-ray diffraction analysis. The surface morphology and elemental analysis of the synthesized films were studied by FESEM and EDAX, respectively. The electrical properties of the Sb2Se3/n-Si heterojunction were considered by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The I-V results of Sb2Se3/n-Si heterojunction diode show a rectifying behavior. The junction ideality factor, barrier height, and series resistance values were extracted from the rectifying curves at different temperatures. The capacitance-voltage results show the abrupt nature of the junction under consideration.
关键词： diode,ideality factor,Antimony selenide,Electron beam,FESEM,XRD
更新于2025-09-09 09:28:46