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Effects of external magnetic field on the micro-structure of diamond-like carbon film prepared by pulsed laser deposition
摘要： The DLC ?lm was deposited by pulsed laser deposition in an external magnetic ?eld, and its optical property, surface morphology and atomic bonds were researched. The simulated ?ight tracks of the carbon ions in the magnetic ?eld showed that a number of the carbon ions were constrained by the Lorentz force, ?ing onto the substrate and forming the DLC ?lm. The contrast between the micro-structures of the DLC ?lms deposited in or out the magnetic ?eld showed that the external magnetic ?eld changed the expansion of the laser-produced plume and con?ned the surface diffusion of the charged particles on the substrate, improving the content of the sp3 bonds in the DLC ?lm.
关键词： pulsed laser deposition,diamond-like carbon ?lm,external magnetic ?eld,optical property,atomic bond
更新于2025-09-23 15:19:57
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Magnetic bipolar transistor based on ZnO/NiO/Si heterostructure using pulsed laser deposition
摘要： Oxide semiconductors are promising candidates for next generation electronics. In this work, magnetic bipolar transistor was fabricated by growing thin films of p-NiO and n-ZnO on n-type silicon wafer by pulsed laser deposition technique with an in-situ annealing at 670○ C in the presence of oxygen. The structural characterization of these films was done by X-ray diffraction and Raman spectroscopy and magnetic properties were studied by vibrating sample magnetometer (VSM). I-V characteristic of fabricated transistor was tested in common emitter configuration with DC biasing. Junction parameters such as ideality factor, series resistance, and transistor parameters like q-point were determined by using conventional transistor output characteristics. The diode and transistor showed an increase in current with the externally applied magnetic field due to the presence of Nickel or Oxygen vacancies in NiO attributing to spin polarized bipolar transport. Therefore the current amplification in these devices can be controlled by spin; making it attractive for spintronic applications.
关键词： oxide semiconductors,pulsed laser deposition,spintronic applications,magnetic bipolar transistor
更新于2025-09-23 15:19:57
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Electrical Properties of Pure NiO and NiO:Ag Thin Films Prepared by Pulsed Laser Deposition
摘要： The electrical properties of pure NiO and NiO:Ag films which are deposited on glass substrate with various dopant concentrations (1wt%, 2wt%, 3wt% and 4wt%) at room temperature and 450 °C annealing temperature will be presented. Further, the structural properties were investigated by X-ray diffraction and the surface morphology of the deposited samples was examined by SEM. The results of the Hall effect showed that all the films were p-type. Hall mobility decreases while both carrier concentration and conductivity increase with the increasing of annealing temperatures and doping percentage, Thus, the behavior of semiconductor, and also the DC conductivity from which the activation energy decreases with the doping concentration increase and transport mechanism of the charge carriers can be estimated.
关键词： Hall effect,Electrical conductivity,NiO:Ag thin films,Pulsed laser deposition
更新于2025-09-23 15:19:57
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Characterization and correlation of microstructure and hardness of Tia??6Ala??4V sheet surface-treated by pulsed laser
摘要： A hot-rolled Tie6Ale4V (Ti-64) sheet was surface-treated by pulsed laser at two different powers (100 and 200 W), with microstructural features and hardness before and after the laser surface treatment (LST) systematically investigated. Results show that after the LST at both powers there are two modi?cation zones with distinct microstructural characteristics: melted zone (MZ) near the laser beam center, completely composed of ?ne martensitic plates with dense {10e11} nanotwins inside them; heat-affected zone (HAZ) far away from the laser beam center, comprised of mixed structures of short-rod b particles, martensitic plates and untransformed bulk a grains. Hardness measurements reveal that the hardness of the Ti-64 sheet can be markedly increased (especially in the MZ) after the LST. In-depth analyses suggest that the hardness increase in the MZ can be ascribed to combined contributions from grain re?nement, presence of nanotwins and solid solution of alloying elements, while only the structural re?nement by ?ne plate structures contributes to hardening in the HAZ. Comparisons between both the LSTed specimens reveal that increasing the laser power from 100 W to 200 W can effectively enlarge the laser-modi?ed zones (both the MZ and the HAZ) and simultaneously re?ne plate structures, leading to further hardness increase.
关键词： Ti-6Ale4V,Hall-petch relation,Hardness,Electron backscatter diffraction,Pulsed laser
更新于2025-09-23 15:19:57
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Embedding of WO3 nanocrystals with rich oxygen-vacancies in solution processed perovskite film for improved photovoltaic performance
摘要： Seeking strategies of promoting the charge separation and transport of the photo-active layer has been always of significance for the development of high-performance optoelectronic devices. We herein demonstrate an effective way of decorating WO3 nanocrystals in perovskite films for boosted photogenerated carriers transport. The WO3 nanocrystals are generated by a simple technique of pulsed laser irradiation in liquid, then introduced into the perovskite film based on the anti-solvent approach. Such decoration is found helpful for the increase of the short-circuit current density (Jsc) of the device, which leads to the increase of the photoconversion efficiency (PCE) from 17.72% to 19.29%. The improved PCE is mainly due to the decoration of the WO3 at the grain boundaries of perovskite films that facilitates the charge transport between the adjacent grains, which is evidenced by the quenching of the film photoluminescence, shortened carrier lifetime, and increased carrier mobility. We thus believe our study provides an effective way of embedding ordinary metal oxides in perovskite films for enhanced optoelectronic performance.
关键词： Hybrid perovskite solar cell,Pulsed laser irradiation in liquid,WO3 nanocrystals,Charge transport,Oxygen-vacancy
更新于2025-09-23 15:19:57
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Polyvinyl Alcohol/Silver nanoparticles film prepared via pulsed laser ablation: An eco-friendly nano-catalyst for 4-nitrophenol degradation
摘要： This work attempts to introduce an eco-friendly nano-catalyst PVA/AgNPs portable film for 4-nitrophenol degradation. Silver nanoparticles (AgNPs) doped Polyvinyl Alcohol (PVA) film has been synthesized via one-potential pulsed laser ablation in liquids (PLAL) technique. The structural, optical, and morphological studies of the synthesized PVA/AgNPs nanocomposite film have been characterized by different techniques such as; XRD, FT-IR, UVeVis, PL, FE-SEM, and EDAX. From X-ray diffraction technique (XRD), it is approved that the synthesized PVA/AgNPs film is polycrystalline with cubic structure form. From UVeVisible spectroscopy, the energy band gap was determined by using tauc relation, which was found to be 3.7eV for direct transition. From morphological study, FE-SEM photos of the synthesized PVA/AgNPs film show the homogeneous distributed spherical-like shape of silver nanoparticles in PVA. The qualitative and semi-quantitative elemental analysis of the prepared samples via EDAX technique confirmed the embedding of the silver nanoparticles in the PVA structure. The amazing performance of the prepared PVA/AgNPs film in catalytic degradation activity for 4-nitrophenol reduction has been investigated, which lead to degrade 93% of 4-nitrrophenol in 25 min.
关键词： Silver nanoparticles,Catalytic degradation,PVA,Pulsed laser ablation,Nitrophenols
更新于2025-09-23 15:19:57
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Silver and copper oxide nanoparticles-decorated graphene oxide via pulsed laser ablation technique: Preparation, characterization, and photoactivated antibacterial activity
摘要： Graphene oxide, silver and copper oxide nanoparticles display photoactivated antibacterial behavior owing to their ability to generate charge carriers via light exposure. In this work, silver nanoparticles (AgNPs) and copper oxide nanoparticles (CuONPs) were embedded through graphene oxide (GO) using laser ablation technique. The microstructural behavior of the synthesized compositions has been investigated via XRD and TEM. The optical properties were studied by (UV–Vis), while the antibacterial properties were investigated in addition to the cell viability towards normal cell line (HFB4) in vitro. The antibacterial activity of GO was enhanced significantly with addition nanoparticles; by meaning, the inhibition zone enlarged from 5.4 mm with pure GO to be around 11.2 mm against E. coli with contribution of CuONPs. This trend of enhancement suggests that GO could be a great platform for different kinds of photo-activated antibacterial to be recommended for versatile biomedical applications.
关键词： CuO,Ag,Pulsed laser ablation,Graphene oxide,Antibacterial activity,Bacterial resistance
更新于2025-09-23 15:19:57
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In situ forming of ternary metal fluoride thin films with excellent Li storage performance by pulsed laser deposition
摘要： In the field of lithium ion battery, conversion-based metal fluoride cathodes are attractive for their excellent theoretical capacity and high voltage. However, the utilization of binary metal fluorides is severely hindered by irreversibility and large voltage hysteresis. The introduction of ternary metal fluorides, like AgCuF3 and CuxFe1-xF2, brings hope to address these shortcomings. To better understand the basic mechanism of conversion reaction in ternary metal fluoride cathodes, the Cu–Fe–F (CFF) thin films were successfully grown in situ by pulsed laser deposition in this work. The physico-chemical properties and electrochemical performance were discussed. Such a CFF solid solution phase presented great cycle stability (82% capacity remains after 100 cycles at current density of 285 mA g?1) and higher energy efficiency (71.8%), which can be attributed to the reversible structural rearrangement after the delithiation process disclosed by ex situ XPS, high-resolution TEM, and selected-area electron diffraction.
关键词： Thin film,Ternary metal fluoride,Lithium ion battery,Pulsed laser deposition
更新于2025-09-23 15:19:57
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Ferroelectric properties and phase transitions of high performance vertically aligned KNN nanowire-arrays grown by pulsed laser deposition
摘要： Pulsed laser deposition (PLD) was used to synthesize piezoelectric nanowire-arrays of K0.5Na0.5NbO3 (KNN) on Pt/TiO2/SiO2/Si substrates. These arrays were successfully prepared by using two different deposition conditions than the previously reported for KNN. KNN with orthorhombic structure and minority secondary phases were identified by XRD. Ferroelectric and Piezoelectric properties were confirmed by piezoresponse force microscopy, and showed that nanowire-arrays have an improvement in their effective piezoelectric coefficient of d33eff = 94.6 pm/V and 133.6 pm/V, higher than previously reported coefficients. Pulsed laser photoacoustic technique was used to analyze the phase transition temperatures and they showed a phase transition (O-T) at ～170 ?C and a phase transition (T-C) at ～360 ?C, lower temperatures than those found for bulk ceramics. Furthermore, it was identified the presence of minor amount of secondary ferroelectric phase (K4Nb6O17).
关键词： Phase transitions,KNN nanowire-arrays,Ferroelectric properties,Pulsed laser deposition,Piezoelectric coefficient
更新于2025-09-23 15:19:57
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Grain Boundaries Limit the Charge Carrier Transport in Pulsed Laser Deposited ?±-SnWO <sub/>4</sub> Thin Film Photoabsorbers
摘要： Recently, α-SnWO4 attracted attention as a material to be used as a top absorber in a tandem device for photoelectrochemical water splitting due to its nearly optimum bandgap of ~1.9?eV and an early photocurrent onset potential of ~0 V vs. RHE. However, the mismatch between the charge carrier diffusion length and light penetration depth—which is typical for metal oxide semiconductors—currently hinders the realization of high photoconversion efficiencies. In this work, the pulsed laser deposition process and annealing treatment of α-SnWO4 thin films are elucidated in order to optimize their charge carrier transport properties. A high temperature treatment is found to enhance the photoconductivity of α-SnWO4 by more than one order of magnitude, as measured with time-resolved microwave conductivity (TRMC). A complimentary analysis by time-resolved terahertz spectroscopy (TRTS) shows that this improvement can be assigned to an increase of the grain size in the heat-treated films. In addition, TRTS reveals electron-hole charge carrier mobilities of up to 0.13 cm2 V-1s-1 in α-SnWO4. This is comparable to values found for BiVO4, which is one of the best performing metal oxide photoanode materials to date. These findings show that there is a significant potential for further improving the properties of α-SnWO4 photoanodes.
关键词： α-SnWO4,metal oxide photoelectrodes,grain boundaries,charge carrier dynamics,pulsed laser deposition
更新于2025-09-23 15:19:57