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Poly‐GeSn Junctionless Thin‐Film Transistors on Insulators Fabricated at Low Temperatures via Pulsed Laser Annealing
摘要： High-performance polycrystalline GeSn (poly-GeSn) junctionless thin-film transistors (JL-TFTs) are proposed and fabricated at low process temperatures. Poly-GeSn thin films with a Sn fraction of 4.8% are prepared using cosputtering and pulsed laser annealing (PLA) techniques. The ultra-rapid nonequilibrium thermodynamic process with 25 ns PLA renders a good crystal GeSn thin film at a low temperature. The ION/IOFF ratio increases by three orders of magnitude with GeSn channel thickness varying from 60 to 10 nm, suggesting that switch-off current is dominated by depletion width. A superior effective mobility of 54 cm2 V-1 s-1 is achieved for the JL-TFT with a 10 nm-thick GeSn film as a consequence of gate/channel interface passivation by oxygen plasma.
关键词： pulsed laser annealing,junctionless thin-film transistors,GeSn
更新于2025-09-11 14:15:04
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Structural, Spectroscopic, and Excitonic Dynamic Characterization in Atomically Thin Yb <sup>3+</sup> ‐Doped MoS <sub/>2</sub> , Fabricated by Femtosecond Pulsed Laser Deposition
摘要： The large area deposition and synthesis of 10 mm × 10 mm atomically thin Yb3+-doped MoS2 films by femtosecond pulsed laser deposition on a silica glass optical platform for device applications are demonstrated for the first time. The presence of Yb3+-ion doping is confirmed using photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The Yb3+-doped MoS2 films, when excited with a 976 nm laser, exhibit room temperature PL with a peak at 1002 nm. The XPS and Raman spectroscopic analyses of the Yb3+-doped and undoped films show that the deposited films are a mixture of 2H- and 1T-MoS2 after postdeposition annealing at 500 °C. The density functional theory analysis shows that the 1T phase is metastable by +77 kJ (≈0.8 eV) mol-1, when compared with the 2H state at 0 K. Ultrafast transient nonlinear optical spectroscopic measurements prove that the saturable absorption of undoped MoS2 is significantly modified after Yb3+-ion doping, by displaying dopant-host structure charge transfer. The complex transient absorption line shape shows a combination of bleach (negative) signals at the A (670 nm) and B (630 nm) exciton energies, and a strong induced absorption below the A exciton level. The results presented herein provide critical insight in designing novel rare-earth-ion doped 2D materials and devices.
关键词： molybdenum disulfide,femtosecond pulsed laser deposition,saturable absorber,rare-earth ion photoluminescence,nonlinear optical properties
更新于2025-09-11 14:15:04
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Manganese oxide nanofoam prepared by pulsed laser deposition for high performance supercapacitor electrodes
摘要： Manganese oxide nanofoam has been prepared by pulsed laser deposition, from a metallic Mn target in a 5 Torr pressure O2 buffer atmosphere. The as-prepared samples were heat-treated at different temperatures (300?C-500?C) in air. Both as-deposited and heat-treated samples have a high porosity foam-like morphology, as shown by Field Emission Scanning Electron Microscopy. High Resolution Transmission Electron Microscopy revealed that the nanofoam is composed by linked nanoparticles with slight crystallization and growth of the nanoparticles due to heat-treatment, which was confirmed by X-ray diffraction, Raman Spectroscopy and X-ray Photoelectron Spectroscopy. These techniques also showed a variable oxide composition upon heat treatment. The supercapacitive properties of manganese oxide nanofoam treated at 300?C exhibited a specific capacitance higher than 1000 F/g, in the 0 to +1.0 V potential range. After heat treatment at 400?C and 500?C, the specific capacitance decreased compared to that of the 300?C treated sample. An increase of about 130% in the initial capacitance was obtained after 500 cycles for this sample. However, it decreases to one third of the maximum value after 5000 cycles. The results shows that the obtained manganese oxide nanofoam has very high specific capacitance but need to improve the cycle stability.
关键词： microstructures,pulsed laser deposition,porous materials,supercapacitors,nanofoam,manganese oxides
更新于2025-09-11 14:15:04
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Pulsed laser deposition with rapid beam deflection by a galvanometer mirror scanner
摘要： A pulsed laser deposition system with rapid beam deflection (RBD-PLD) by a galvanometer mirror scanner has been developed for alternating ablation of multiple targets with a single laser instrument. In this system, the alternating deposition of different target materials is carried out by scanning the laser beam between the positionally fixed targets with a galvanometer mirror instead of mechanically switching the target positions on a fixed optical path of the laser beam as is done in conventional pulsed laser deposition (PLD) systems. Thus, the “wait” time required for switching target materials to be deposited, which typically takes several seconds in a conventional system, can be made as short as a few milliseconds. We demonstrate some of the advantages of this PLD system in several technologically important aspects of thin film synthesis: (1) fast fabrication of binary alloy films, (2) preparation of natural composition spread libraries, (3) effect of the target switching time on the deposition of volatile compounds, (4) control of the degree of mixing of two different materials in a film, and (5) efficient growth of compositionally graded thin films.
关键词： galvanometer mirror scanner,rapid beam deflection,composition spread libraries,volatile compounds,pulsed laser deposition,thin film synthesis,compositionally graded thin films,binary alloy films
更新于2025-09-11 14:15:04
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A review on glass welding by ultra-short laser pulses
摘要： Glass welding by ultra-short pulsed lasers is a piece of technology that offers high strength joints with hermetic sealing. The joints are typically formed in glass that is transparent to the laser by exploiting nonlinear absorption effects that occur under extreme conditions. Though the temperature reached during the process is on the order of a few 1000 °C, the heat affected zone (HAZ) is confined to only tens of micrometers. It is this controlled confinement of the HAZ during the joining process that makes this technology so appealing to a multitude of applications because it allows the foregoing of a subsequent tempering step that is typically essential in other glass joining techniques, thus making it possible to effectively join highly heat sensitive components. In this work we give an overview on the process, development and applications of glass welding by ultra-short pulsed lasers.
关键词： ultra-short pulsed laser processing,glass joining,USP glass welding,brittle materials
更新于2025-09-11 14:15:04
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Long-term stabilized high-density CuBi <sub/>2</sub> O <sub/>4</sub> /NiO heterostructure thin film photocathode grown by pulsed laser deposition
摘要： Harvesting sustainable hydrogen through water-splitting requires a durable photoelectrode to achieve high efficiency and long lifetime. Dense, uniform CuBi2O4/NiO thin film photocathodes grown by pulsed laser deposition achieved photocurrent density over 1.5 mA cm-2 at 0.4 VRHE and long-term chronoamperometric stability for over 8 hours.
关键词： heterostructure,pulsed laser deposition,water-splitting,CuBi2O4,NiO,hydrogen,photocathode
更新于2025-09-11 14:15:04
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Doping nanoparticles using pulsed laser ablation in a liquid containing the doping agent
摘要： While doping of semiconductors or oxides is crucial for numerous technological applications, its control remains difficult especially when the material is reduced down to the nanometric scale. In this paper, we show that pulsed laser ablation of an undoped solid target in an aqueous solution containing activator ions offers a new way to synthesise doped-nanoparticles. The doping efficiency is evaluated for laser ablation of an undoped Gd2O3 target in aqueous solutions of EuCl3 with molar concentration from 10?5 mol L?1 to 10?3 mol L?1. Thanks to luminescence experiments, we show that the europium ions penetrate the core of the synthesised monoclinic Gd2O3 nanoparticles. We also show that the concentration of the activators in the nanoparticles is proportional to the initial concentration of europium ions in the aqueous solution, and a doping of about 1% ([Eu]/[Gd] atomic ratio) is reached. On the one hand, this work could open new ways for the synthesis of doped nanomaterials. On the other hand, it also raises the question of undesired penetration of impurities in laser-generated nanoparticles in liquids.
关键词： EuCl3,doping,luminescence,pulsed laser ablation,Gd2O3,nanoparticles
更新于2025-09-11 14:15:04
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Influence of different post-annealing temperatures on physical properties of La0.72Ca0.28MnO3:Ag0.2 thin films by pulsed laser deposition technique
摘要： La0.72Ca0.28MnO3:Ag0.2/LaAlO3 (100) thin ?lms, prepared by pulsed laser deposition, were post-annealed at di?erent temperatures in air. X-ray di?raction technique were used to analysize the orientation and lattice parameter, atomic force microscope (AFM) and scanning electronic microscope (SEM) were employed to characterize the surface morphology of the thin ?lms. Resistance vs. temperature (R-T) behaviors of the thin ?lms were tested with standard four-probe technique. The surface morphology results show that the grain size increases and crystalline quality of the ?lms are improved with increased annealing temperature up to 1200 °C, while the amount of grains also increases; R-T results illustrate that both the temperature coe?cient of resistance (TCR) and metal-insulator transition temperature (TMI) of the ?lms, increase with annealing temperature. In particular, TCR of thin ?lm (post-annealing at 1200 °C) reaches 28.8%·K?1, which makes such ?lms be promisingly applicated in thermal detectors near the room temperature.
关键词： Pulsed laser deposition technique,Electrical properties,La0.72Ca0.28MnO3:Ag0.2 thin ?lms,Surface morphology
更新于2025-09-11 14:15:04
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The preparation and properties of the C-doped modified layers on uranium surfaces by pulsed laser irradiating
摘要： The C-doped modi?ed layer on uranium surface was prepared by pulsed laser irradiating in methane atmosphere. The microstructure of the obtained layer was characterised by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The results show that the obtained layer is a composite layer with a gradual transition structure from UO2/free carbon to UO2-x/UCxOy/free carbon to UC1-xOy/UC, and eventually to metallic U. To investigate the oxidation mechanism of the C-doped modi?ed layer, initial oxidation behavior of O-rich surface and O-poor surface obtained after sputtering for 7 min and 60 min were studied by XPS. And the results illustrate that UCxOy with U 4f7/2 binding energy at 379.5 eV in the O-rich region is more resistant to oxidation than UC1-xOy/UC under oxygen exposure. Free carbon is distributed in the surface layer of C-doped modi?ed layer prepared by pulsed laser irradiating, and the free carbon is also formed after oxidation of UC1-xOy, UC and UCxOy at room temperature. We speculate that the aggregation of free carbon increases the ability to prevent the inward diffusion of O atoms. Moreover, the results of the potentiodynamic polarization tests show that the C-doped modi?ed layer improved the corrosion protective properties of metallic U. The self-corrosive potential and self-corrosive current of the C-doped modi?ed layer are ?1.47 × 10?1 V vs. SCE and 9.46 × 10?8 A/cm2, respectively, while the values of metallic U are ?5.67 × 10?1 V vs. SCE and 8.08 × 10?7 A/cm2, respectively.
关键词： Microstructure,Uranium oxy-carbide,Pulsed laser modi?cation,Oxidation behavior,Uranium C-Doped modi?ed layer
更新于2025-09-11 14:15:04
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Ferroelectric/photoluminescence effect in Pr-doped (Bi0.5Na0.5)TiO3–BaTiO3 thin film fabricated by the pulsed laser deposition method
摘要： In this work, (100)-oriented Pr-doped (Bi0.5Na0.5)TiO3–BaTiO3 ferroelectric/photoluminescence film was fabricated on SrRuO3-electroded Pb(Mg1/3Nb2/3)O3–PbTiO3 single-crystal substrate. The phase structure, domain, ferroelectric, and photoluminescence performance were studied. Results indicated the Pr-BNBT thin film has pure phase structure, dense microstructure, and exhibited (100) orientation out of the plane. Well-defined ferroelectric hysteresis loop with the remanent polarization of ~ 18?μC/cm2 and obvious photoluminescence emission spectrum were obtained. Based on the piezoresponse force microscopy, the ferroelectric domain structure was characterized and the domain size was ~ 100?nm. The present ferroelectric/photoluminescence multifunctional thin film has potential for multifunctional MEMS actuator and optical devices.
关键词： Thin film,Pr-doped,Ferroelectric,Photoluminescence,Pulsed laser deposition
更新于2025-09-11 14:15:04