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Latent tracks and novel infrared waveguide formation in lithium tantalate irradiated with swift heavy ions
摘要： In this work, the formation mechanisms of latent ion tracks and infrared-light waveguides in ion-irradiated LiTaO3 single crystals were comparatively studied using 200 MeV Kr17+ irradiation at a fluence of 1 × 1012 cm?2 and 247 MeV Ar12+ irradiation at fluences of 1 × 1012 cm?2 and 3 × 1012 cm?2. Because of the intense electronic energy loss, the produced lattice disorder and formed latent track were experimentally determined through complementary techniques, including the analysis of transmission electron microscopy patterns and Rutherford backscattering/channeling spectra. Corresponding to different ions with different irradiation energies and electronic energy losses, the related spatio-temporal evolutions of lattice temperatures in Kr17+- and Ar12+-irradiated LiTaO3 crystals were numerically calculated using the inelastic thermal spike model. The simulation results theoretically describe the experimentally observed lattice disorder and latent track behaviors. The lattice swelling in the latent-ion-track regions was demonstrated using high-resolution x-ray diffraction patterns; the lattice swelling resulted in a decrease in the refractive index, thereby providing a path to tailor the optical properties and fabricate the waveguide structure. Optical measurements and simulations indicated that the formed LiTaO3 waveguide could effectively support the guided modes and confine the light propagation, especially in the infrared region.
关键词： swift heavy ion irradiation,latent ion track,electronic energy loss,infrared waveguide
更新于2025-11-14 17:04:02
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Electronic transport in MoSe <sub/>2</sub> FETs modified by latent tracks created by swift heavy ion irradiation
摘要： Unique characteristics of transition metal dichalcogenides (TMDCs) such as their tunable band gap and ultra-thin body thickness make them potential candidates for applications in optoelectronic, gas sensing and energy storage devices. In this work, 1.8 GeV Ta ions at different ion fluences ranging from 1 × 109 ions cm?2 to 6 × 1010 ions cm?2 were used to introduce amorphous defective regions, latent tracks, in MoSe2 to study the electronic transport behavior in irradiated TMDC-channel field-effect transistors (FETs). Defects in these materials induced by the swift heavy ion irradiation play a vital role in the device applications. The results show that carrier mobility decreases while resistance of the devices increases abruptly with increasing ion fluences. The impact mechanism of the latent tracks on electronic transport behavior in TMDC-channel FETs was analyzed in detail. It was assumed that the Bloch wave of electrons was strongly localized by the latent tracks induced by the SHI irradiation and the Bloch wave of electrons can be scattered by the latent tracks as well. This study helps to investigate the influence of the latent tracks on electronic transport in other 2D materials as well.
关键词： latent track,field-effect transistor,molybdenum selenide,electronic transportation,swift heavy ion irradiation
更新于2025-11-14 17:03:37
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Variation in Structural, Electrical and Optical Properties of Selenium Nanowires After Irradiation with Ni6+ Ions
摘要： The effect of Ni ion irradiation on selenium nanowires of 80 nm diameter is studied in the present work. Se nanowires were prepared by using electrodeposition technique in polycarbonate membrane. Changes in the structural, optical and electrical properties are studied using XRD, UV/Vis spectroscopy and current–voltage characteristics, of the pristine and irradiated samples. X-ray diffraction study confirms the variation in peak intensity without any shifting in peak position. Variation in texture coefficient and grain size was clearly observed which is a consequence of changing plane orientation, irradiation induced grain growth and grain fragmentation. A decrease in the optical band gap takes place due to interstitial energy band states in the vicinity of conduction and valence band. IVC also shows variation in the conductivity which is due to the generation of current carriers with the passage of energetic ions.
关键词： Ion irradiation,Optical analysis,Selenium nanowires,Impedance,Electrical properties,Structural analysis
更新于2025-09-23 15:23:52
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Perforating Freestanding Molybdenum Disulfide Monolayers with Highly Charged Ions
摘要： Porous single layer molybdenum disulfide (MoS2) is a promising material for applications such as DNA sequencing and water desalination. In this work, we introduce irradiation with highly charged ions (HCIs) as a new technique to fabricate well-defined pores in MoS2. Surprisingly, we find a linear increase of the pore creation efficiency over a broad range of potential energies. Comparison to atomistic simulations reveals the critical role of energy deposition from the ion to the material through electronic excitation in the defect creation process, and suggests an enrichment in molybdenum in the vicinity of the pore edges at least for ions with low potential energies. Analysis of the irradiated samples with atomic resolution scanning transmission electron microscopy reveals a clear dependence of the pore size on the potential energy of the projectiles, establishing irradiation with highly charged ions as an effective method to create pores with narrow size distributions and radii between ca. 0.3 and 3 nm.
关键词： 2D material,perforation,ion irradiation,MD simulation,molybdenum disulfide,highly charged ions,STEM
更新于2025-09-23 15:22:29
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Effects of flux pinning on the DC characteristics of meander-shaped superconducting quantum interference filters with flux concentrator
摘要： Superconducting quantum interference filters, or SQIFs, are a promising class of highly sensitive magnetometers benefiting from a highly peaked and symmetric magnetic response at zero-input flux. They can be used in magnetometry, e.g., in wideband applications. A simple solution to increase further their sensitivity is to add a superconducting flux concentrator (SFC) to their design. Using the ion irradiation process, we designed a meander-shaped SQIF enhanced with an SFC. The SFC improved the SQIF transfer factor by a factor of 8.4. However, high temperature superconducting (HTSc) devices are vulnerable to flux pinning, which can severely hinder their response. On the one hand, HTSc technologies alleviate the burden of cryogenics. On the other hand, applications that use SFCs in noisy and unshielded environments will become possible only if a better understanding of how this flux impacts the device's properties is achieved. We studied the relationship between the field present during the cooling process of the SQIF antenna (thereafter called 'cooling field') and the evolution of its DC response. We developed a simple and phenomenological model and were able to reproduce the degradation of the SQIF response. This work demonstrates the usability of SFC-enhanced SQIFs based on ion irradiated junctions in rather harsh conditions, in particular, an unshielded environment, and also gives an insight into the implications that such conditions cause on the application of SFCs in general.
关键词： ion irradiation,flux pinning,magnetometry,flux concentrator,superconducting quantum interference filters
更新于2025-09-23 15:22:29
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Ion beam engineering of morphological, structural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film
摘要： Development of plasmonic nanocomposite coatings with tunable optical and photocatalytic properties is important for diverse technological applications. In this paper, we report modifications in the microstructural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film by 8 MeV Si3+ ion irradiation. Ag-TiO2-PVA nanocomposite thin films on silica glass were prepared by a combination of sol-gel method and spin coating. Ion irradiation induced morphological evolution of Ag-TiO2-PVA thin film was studied by atomic force microscopy and field emission scanning electron microscopy, which revealed interesting changes in the size distribution of nanostructures with increasing ion fluence. Ion irradiation of the Ag-TiO2-PVA thin film resulted in the emergence of SPR peak of Ag nanoparticles at 456 nm, which shifted to 446 nm along with enhancement in intensity as the ion fluence was increased. Significant enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin film for degradation of methylene blue was observed upon ion irradiation at 1 × 1013 ions/cm2. The origins of microstructural, morphological, optical and plasmonic modifications and enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin films have been discussed.
关键词： Ion irradiation,Surface plasmon resonance,Nanocomposite,Photocatalysis,Ag-TiO2-PVA
更新于2025-09-23 15:22:29
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Fluorescent Nanodiamonds || Producing Fluorescent Nanodiamonds
摘要： Natural diamonds in colors are commonly known as fancies, or fancy color diamonds, in gemstone industries. They are rare, beautiful, and some even carry impressive price tags in the jewelry market. By comparison, micro‐ and nanoscale diamond powders are low in price, with or without colors and fluorescent or not. These powders have been used as abrasives for grinding and polishing purposes since ancient time, mainly because of their extraordinary hardness. Little or no attention has been paid over the centuries to other properties of nanodiamonds such as their innate biocompatibility and light‐emitting capability. The invention of fluorescent nanodiamond (FND) in 2005 has revolutionized the field, opening a new area of research and development with diamonds. Experiments with FNDs in the last decade have demonstrated various promising applications of surface‐functionalized FNDs in diversified fields, ranging from physics and chemistry to biology and medicine. It is worthy of noting that as originated from the discovery of Radium by Marie Sk?odowska Curie (Section 3.2), FNDs may very well be called Madame Curie’s gemstones, valued appropriately as a scientist’s best friend.
关键词： fluorescent nanodiamonds,magnetically modulated fluorescence,fluorescence lifetime,size reduction,FND,ion irradiation,H3 centers,nitrogen-vacancy centers,electron irradiation,NV centers
更新于2025-09-23 15:21:01
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Fluorinated graphene nanoparticles with 1-3 nm electrically active graphene quantum dots
摘要： A new perspective approach to how to create a new and locally nanostructured graphene-based material is reported on. We studied the electric and structural properties for the partially fluorinated graphene (FG) films obtained from a FG-suspension and nanostructured by high-energy Xe ions. Local shock heating in ion tracks is suggested to be the main driving force of the changes. It was found that ion irradiation leads to the formation of locally thermal expanded FG and its cracking into nanosized nanoparticles with embedded small (~1.5-3 nm) graphene quantum dots, which band gap was estimated as 1-1.5 eV, into them. A further developed approach was applied to correction of the functional properties of the printed FG-based crossbar memristors. Dielectric FG films with small quantum dots may offer prospects in graphene-based electronics due to their stability and promising properties.
关键词： memristor,molecular dynamics simulation,nanostructuring,swift ion irradiation,fluorinated graphene,graphene quantum dots
更新于2025-09-23 15:21:01
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In-field dependences of the critical current density J in GdBa2Cu3O7-d coated conductors produced by Zr irradiation and post-annealing at low temperatures
摘要： We report the influence of 6 MeV Zr4+ irradiation and post-irradiation annealing (200 °C) in the in-field dependences of the critical current densities Jc of 1.3 μm thick GdBa2Cu3O7-d coated conductors grown by co-evaporation. Samples were irradiated with 6 MeV Zr4+ and fluences between 2.3 × 10^11 cm^-2 and 3 × 10^12 cm^-2. The correlation between the superconducting critical temperature Tc and in-field dependences of Jc has been analyzed. In addition, random disorder introduced by irradiation was reduced by thermal annealed at 200 °C. The analysis of our experimental findings indicates that the optimal irradiation (reducing random disorder by annealing) results in the suppression of the self-field Jc of ≈10% and in-field Jc enhancements nearly doubled at about 5 T. A clear correlation between Tc, disorder and self-field Jc is observed. Additional random disorder and nanoclusters suppress systematically Tc and increase the flux creep relaxation at intermediate temperatures (reducing the characteristic glassy μ value).
关键词： E. Ion irradiation,A. Coated conductors,D. Critical current densities
更新于2025-09-19 17:15:36
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Grayscale Nanopatterning of Phase-Change Materials for Subwavelength-Scaled, Inherently Planar, Nonvolatile, and Reconfigurable Optical Devices
摘要： The integration of phase-change materials into the design of optical metasurfaces already enables dynamically switchable, tunable, and reconfigurable optical devices. Their functionality is based on fast and repeatable switching between two stable states - amorphous and crystalline - which is typically accompanied by drastic changes of the electrical and optical properties and can be accomplished by external stimuli. In this study, we demonstrate that focused ion beam irradiation can be used to locally tailor the amount of disorder in phase-change materials in highly confined regions, which was examined both in the visible and mid infrared by using optical nano-imaging techniques such as photo-induced force microscopy and scattering type scanning near-field optical microscopy. Our approach enables grayscale patterning at the nanoscale circumventing the diffraction limit of common laser light sources and thus literally adds a further degree of freedom for the design of optical devices that are subwavelength-scaled, inherently planar, nonvolatile, and reconfigurable.
关键词： focused ion irradiation,grayscale,tailoring disorder,nanopatterning,phase-change materials,nano-imaging
更新于2025-09-19 17:13:59