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Characterization of MgO/TiN bilayer deposited on cube-textured copper using pulsed-laser deposition technique
摘要： Here we demonstrate heteroepitaxial growth of MgO/TiN thin films on flexible metal foil of copper substrates using pulsed laser deposition. X-ray and electron diffraction measurements revealed that the epitaxial MgO/TiN bilayer was oriented along (002) direction. The large mismatch between TiN islands and Cu substrate was effectively reduced by the 5/6 and 6/7 variations of domains. Despite the local irregularity of misfit dislocations at TiN/Cu, the domain-matching epitaxy paradigm is a remarkably accurate theory. MgO/TiN bilayer is chemically homogeneous and Mg, Ti, or Cu atoms do not segregate into the low-angle grain boundaries regardless of MgO/TiN films thickness. Thus, it appears that thickness may be reduced up to the value in which TiN fully covers the rough surface of Cu tape. Unfortunately, issues related to the presence of in-plane TiN contraction, probably generated by the difference in thermal expansion coefficient, and the origin of misfit dislocations irregularity at TiN/Cu interface remain unresolved. Our findings can make a substantial contribution to further research on Cu-based coated conductors and help in better understanding the ways that MgO/TiN bilayer are grown on Cu tape.
关键词： titanium nitride,pulsed-laser deposition,magnesium oxide,copper,growth,epitaxy,domain-matching epitaxy
更新于2025-09-19 17:13:59
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The effect of pulse duration on nanoparticle generation in pulsed laser ablation in liquids: Insights from large-scale atomistic simulations
摘要： The generation of colloidal solutions of chemically clean nanoparticles through pulsed laser ablation in liquids (PLAL) has evolved into a thriving research field that impacts industrial applications. The complexity and multiscale nature of PLAL make it difficult to untangle the various processes involved in the generation of nanoparticles and establish the dependence of nanoparticle yield and size distribution on the irradiation parameters. Large-scale atomistic simulations have yielded important insights into the fundamental mechanisms of ultrashort (femtoseconds to tens of picoseconds) PLAL and provided a plausible explanation of the origin of the experimentally observed bimodal nanoparticle size distributions. In this paper, we extend the atomistic simulations to short (hundreds of picoseconds to nanoseconds) laser pulses and focus our attention on the effect of the pulse duration on the mechanisms responsible for the generation of nanoparticles at the initial dynamic stage of laser ablation. Three distinct nanoparticle generation mechanisms operating at different stages of the ablation process and in different parts of the emerging cavitation bubble are identified in the simulations. These mechanisms are (1) the formation of a thin transient metal layer at the interface between the ablation plume and water environment followed by its decomposition into large molten nanoparticles, (2) nucleation, growth, and rapid cooling/solidification of small nanoparticles at the very front of the emerging cavitation bubble, above the transient interfacial metal layer, and (3) spinodal decomposition of a part of the ablation plume located below the transient interfacial layer, leading to the formation of a large population of nanoparticles growing in a high-temperature environment through inter-particle collisions and coalescence. The coexistence of the three distinct mechanisms of the nanoparticle formation at the initial stage of the ablation process can be related to the broad nanoparticle size distributions commonly observed in nanosecond PLAL experiments. The strong dependence of the nanoparticle cooling and solidification rates on the location within the low-density metal-water mixing region has important implications for the long-term evolution of the nanoparticle size distribution, as well as for the ability to quench the nanoparticle growth or dope them by adding surface-active agents or doping elements to the liquid environment.
关键词： phase explosion,pulsed laser ablation in liquids,molecular dynamics simulations,hydrodynamic instability,atomistic simulations,nanoparticles,nucleation and growth
更新于2025-09-19 17:13:59
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Advanced multimodal laser imaging tool for urothelial carcinoma diagnosis (AMPLITUDE)
摘要： The paper presents an overview and concept of the European Union Horizon 2020 project “AMPLITUDE - Advanced Multimodal Photonics Laser Imaging Tool for Urothelial Diagnosis in Endoscopy”. The project aims at the development of a novel label-free, multi-modal imaging tool for urothelial cancer diagnosis and therapy monitoring based on ultrafast fiber laser operating in the 3rd biological window with frequency doubling and additional 785 nm CW laser for Raman spectroscopy. The tool corresponds to clinical needs for better diagnosis of the pathohistological staging of tumours and in-vivo endoscopic assessment of depth of lesion invasiveness.
关键词： 3rd biological window,multiphoton imaging,bladder cancer,confocal microscopy,short-pulsed laser
更新于2025-09-19 17:13:59
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A Study on the Effect of Ultrashort Pulsed Laser Texturing on the Microstructure and Properties of Metastable S Phase Layer formed on AISI 316L Surfaces
摘要： Austenitic stainless steels (ASS) are an important material within the food and medical industries. However, their current limitations of poor wear resistance and susceptibility to bacterial colonisation have limited further uptake. Low-temperature plasma nitriding can address the poor durability of the ASS alloys by forming the S phase, therefore, providing combined improvement in hardness, wear resistance and corrosion resistance. Additionally, pulsed laser texturing can also be used to introduce functional antibacterial textures. However, due to the thermal nature of laser patterning and the thermodynamic metastability of the S phase, almost no research has been conducted thus far on combining the technologies. Therefore, this study for the first time has investigated the response of S phase treated surfaces to ultrashort (nano and femtosecond) laser texturing. The results have shown that, both theoretically and in practice, laser pulses within the nanosecond regime led to the damage of the surface, decomposition of the metastable S phase and loss of the corrosion resistance. In contrast, no change of the S phase surface layer could be detected following femtosecond laser texturing. Hence, demonstrating the feasibility of texturing S phase surfaces using femtosecond pulsed lasers, thus paving the way towards long-lasting multi-functional antibacterial stainless steel surfaces.
关键词： low-temperature nitriding,active-screen plasma,S phase,AISI 316L,thermal stability,pulsed laser texturing
更新于2025-09-19 17:13:59
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Ferroelectric properties of gradient doped Y <sub/>2</sub> O <sub/>3</sub> :HfO <sub/>2</sub> thin films grown by pulsed laser deposition
摘要： A HfO2-based thin ?lm is a nanoscale ferroelectric material with a high-k dielectric and CMOS compatibility, which make it a promising candidate for high-performance electronics. Here, we demonstrate the synthesis of a ferroelectric Y-doped HfO2 (HYO) thin ?lm by pulsed laser deposition. This HYO thin ?lm is gradient doped by alternately depositing a HfO2 ceramic target and a Y2O3 ceramic target. In the ?lms, the orthorhombic phase, ferroelectric phase, is proved by grazing incidence x-ray diffraction and scanning transmission electron microscopy measurements. Moreover, the HYO thin ?lm embraces outstanding ferroelectric and dielectric properties, its remanent polarization is up to 10.5 lC/cm2, and the dielectric constant is 27. The 180(cid:2) inversion of the domain can be observed in a piezoelectric power microscopy image, while the phase contrast of the write domain fades with time. Therefore, this work provides a reliable approach to obtain a ferroelectric HYO thin ?lm, which enables great potential in future high-performance nanoelectronics.
关键词： pulsed laser deposition,Y-doped,ferroelectric,thin film,HfO2
更新于2025-09-19 17:13:59
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Fabrication of silicon carbide nanoparticles using picosecond pulsed laser ablation in acetone with characterizations from TEM and XRD
摘要： We fabricated SiC nanoparticles (NPs) using a laser ablation method in acetone with a picosecond pulsed laser and characterized the resulting sizes, shapes, and crystal structures using transmission electron microscopy (TEM) and X-ray diffraction (XRD). We revealed two formation processes for the SiC NPs. The main process was the formation of spherical NPs with diameters primarily less than 10 nm. The crystal structure was 3C-SiC, which did not depend on a target polytype. Therefore, it is concluded that these NPs are grown from atomic molecules that disassociate from targets in the ablation process. As a result of a Rietbelt analysis of the XRD patterns, we clearly found that almost all NPs were single crystals. In addition, a stacking fault in the crystal was observed in the TEM image, which affects the XRD pattern. The other process was the formation of NPs with diameters from 30 to 80 nm with crystal structures that were the same as the targets. This indicates that these NPs were generated as fragments of the target. Our findings are useful for applications of SiC NPs to selectively control their size, shape, and crystal structure using laser ablation.
关键词： silicon carbide nanoparticles,3C-SiC,picosecond pulsed laser ablation,TEM,XRD
更新于2025-09-19 17:13:59
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Synthesis and Deposition of Ag Nanoparticles by Combining Laser Ablation and Electrophoretic Deposition Techniques
摘要： Silver nanostructured thin films have been fabricated on silicon substrate by combining simultaneously pulsed laser ablation in liquid (PLAL) and electrophoretic deposition (ED) techniques. The composition, topography, crystalline structure, surface topography, and optical properties of the obtained films have been studied by energy dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and UV-visible spectrophotometry. The coatings were composed of Ag nanoparticles ranging from a few to hundred nm. The films exhibited homogenous morphology, uniform appearance, and a clear localized surface plasmon resonance (LSPR) around 400 nm.
关键词： pulsed laser ablation in liquid,electrophoretic deposition,silver nanoparticles
更新于2025-09-19 17:13:59
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Self-assembly of a lateral quasi-Ohmic CuInSe <sub/>2</sub> /InSe isotype heterojunction for flexible devices by pulsed laser deposition
摘要： The contacts between two-dimensional InSe films and metal electrodes play an important role in nanoelectronics flexible devices. Generally, there is a large work function difference between the Au and InSe films, which would form a Schottky contact to deteriorate device performances. Herein, we designed a lateral self-assembled CuInSe2/InSe isotype heterojunction on a flexible mica substrate by pulsed laser deposition, which could improve the contact performances between electrodes and InSe films. By combining the X-ray photoelectron spectroscopy and Kelvin probe force microscopy results, the In rich CuInSe2 and InSe regions could act as quasi-n+-n junctions for reduction of the contact resistance with electrodes. Compared to the InSe films with Au electrodes, the CuInSe2/InSe isotype heterojunction presents approximately half channel resistance and four times photocurrent values. Moreover, the heterojunction devices can still maintain relatively good performance under bending states by restraining the dark current. The present work proves the potential of CuInSe2/InSe isotype heterojunctions for flexible applications.
关键词： pulsed laser deposition,flexible devices,isotype heterojunction,CuInSe2/InSe,quasi-Ohmic contact
更新于2025-09-19 17:13:59
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Comparative Study of the Structure, Composition, and Electrocatalytic Performance of Hydrogen Evolution in MoSx~2+?′/Mo and MoSx~3+?′ Films Obtained by Pulsed Laser Deposition
摘要： Systematic and in-depth studies of the structure, composition, and efficiency of hydrogen evolution reactions (HERs) on MoSx films, obtained by means of on- and off-axis pulsed laser deposition (PLD) from a MoS2 target, have been performed. The use of on-axis PLD (a standard configuration of PLD) in a buffer of Ar gas, with an optimal pressure, has allowed for the formation of porous hybrid films that consist of Mo particles which support a thin MoSx~2+δ (δ of ~0.7) film. The HER performance of MoSx~2+δ/Mo films increases with increased loading and reaches the highest value at a loading of ~240 μg/cm2. For off-axis PLD, the substrate was located along the axis of expansion of the laser plume and the film was formed via the deposition of the atomic component of the plume, which was scattered on Ar molecules. This made it possible to obtain homogeneous MoSx~3+δ (δ~0.8–1.1) films. The HER performances of these films reached saturation at a loading value of ~163 μg/cm2. The MoSx~3+δ films possessed higher catalytic activities in terms of the turnover frequency of their HERs. However, to achieve the current density of 10 mA/cm2, the lowest over voltages were ?162 mV and ?150 mV for the films obtained by off- and on-axis PLD, respectively. Measurements of electrochemical characteristics indicated that the differences in the achievable HER performances of these films could be caused by their unique morphological properties.
关键词： nanocatalysts,buffer gas,pulsed laser deposition,transition metal chalcogenides,hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Pulsed laser deposition of antimony selenosulfide thin film for efficient solar cells
摘要： Antimony selenosul?de, Sb2(SxSe1(cid:2)x)3, has been considered as a promising light harvesting material for low-cost, non-toxic, and stable solar cell applications. However, current preparation methods of Sb2(SxSe1(cid:2)x)3 suffer from low-quality ?lms, which hampers the performance improvement in Sb2(SxSe1(cid:2)x)3-based solar cells. Herein, we develop a pulsed laser deposition technique to fabricate antimony selenosul?de ?lms with ?at and compact surface morphology and high crystallinity. The composition of the as-obtained ?lms can be conveniently tuned via varying molar ratios of Sb2S3 and Se in targets. At optimized conditions, we fabricate planar heterojunction solar cells and then obtain a signi?cantly improved power conversion ef?ciency of 7.05%. Our research offers a facile and robust preparation method for Sb2(SxSe1(cid:2)x)3 ?lms with enhanced photovoltaic properties.
关键词： antimony selenosulfide,photovoltaic properties,thin film,pulsed laser deposition,solar cells
更新于2025-09-19 17:13:59