- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Characterization of a double Time-Of-Flight detector system for accurate velocity measurement in a storage ring using laser beams
摘要： The Isochronous Mass Spectrometry (IMS) is a powerful tool for mass measurements of exotic nuclei with half-lives as short as several tens of micro-seconds in storage rings. In order to improve the mass resolving power while preserving the acceptance of the storage ring, the IMS with two Time-Of-Flight (TOF) detectors has been implemented at the storage ring CSRe in Lanzhou, China. Additional velocity information beside the revolution time in the ring can be obtained for each of the stored ions by using the double TOF detector system. In this paper, we introduced a new method of using a 658 nm laser range finder and a short-pulsed ultra-violet laser to directly measure the distance and time delay difference between the two TOF detectors which were installed inside the 10?11 mbar vacuum chambers. The results showed that the distance between the two ultra-thin carbon foils of the two TOF detectors was ranging from 18032.5 mm to 18035.0 mm over a measurable area of 20×20 mm2. Given the measured distance, the time delay difference which comes with signal cable length difference between the two TOF detectors was measured to be ??????????????1?2 = 99(26) ps. The new method has enabled us to use the speed of light in vacuum to calibrate the velocity of stored ions in the ring. The velocity resolution of the current double TOF detector system at CSRe was deduced to be ??(??)∕?? = 4.4 × 10?4 for laser light, mainly limited by the time resolution of the TOF detectors.
关键词： Ultra-high vacuum,Ultra-thin carbon foil,TOF detectors,Velocity measurement,Laser range-finder,ps-pulsed UV laser
更新于2025-11-25 10:30:42
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Constructing electrostatic self-assembled 2D/2D ultra-thin ZnIn2S4/protonated g-C3N4 heterojunctions for excellent photocatalytic performance under visible light
摘要： 2D/2D ultra-thin ZnIn2S4/protonated g-C3N4 nanocomposites (ZnIn2S4/pCN) are fabricated by electrostatic self-assembly strategy between negatively charged 2D ultra-thin ZnIn2S4 nanosheets and 2D protonated g-C3N4 nanosheets. The optimized ZnIn2S4/pCN (5:3) shows excellent photocatalytic activity toward H2 production (~8601.16 μmol·g?1·h?1) under visible light. In addition, ZnIn2S4/pCN also exhibits superior visible-light-driven photocatalytic tetracycline degradation efficiency, about ~4.13 and ~2.28 times higher than protonated g-C3N4 and ultra-thin ZnIn2S4, respectively. The optimal ZnIn2S4/pCN (5:3) also has good photostability. The excellent photocatalytic activity of ZnIn2S4/pCN can be attributed to the unique 2D/2D heterojunctions, which are obtained by electrostatic self-assembly. The intimate interfacial contact and larger contact areas promote the separation and migration of photogenerated carriers, which contribute to the improvement of photocatalytic activity and photostability. Our research on the 2D/2D nanocomposites provides a scalable solution for the research of efficient and active photocatalysts.
关键词： protonated g-C3N4,ultra-thin ZnIn2S4 nanosheets,electrostatic self-assembly,2D/2D
更新于2025-11-19 16:46:39
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Templated direct growth of ultra-thin double-walled carbon nanotubes
摘要： Double-walled carbon nanotubes (DWCNTs) combined the advantages of multi-walled (MW-) and single-walled (SW-) CNTs can be obtained by transforming the precursors (e.g. fullerene, ferrocene) into thin inner CNTs inside SWCNTs as templates. However, this method is limited since the DWCNT yield is strongly influenced by the filling efficiency (depending on the type of the filled molecules), opening and cutting the SWCNTs, and the diameter of the host SWCNTs. Therefore, it cannot be applied to all types of SWCNT templates. Here we show a universal route to synthesize ultra-thin DWCNTs via making SWCNTs stable at high temperature in vacuum. This method applies to different types of SWCNTs including metallicity-sorted ones without using any precursors since the carbon sources were from the reconstructed SWCNTs and the residue carbons. The resulting DWCNTs are with high quality and the yield of inner tubes is comparable to/higher than that of the DWCNTs made from the transformation of ferrocene/fullerene peapods.
关键词： Double-walled carbon nanotubes,ultra-thin,high-temperature annealing,DWCNTs,SWCNTs
更新于2025-11-14 15:16:37
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Initial Investigation for the Fabrication of Hyperbolic Metamaterials Based on Ultra-Thin Au Layers
摘要： In this paper, we will present the fabrication possibilities developed within our group for obtaining multilayer hyperbolic metamaterials (HMMs). The minimum metallic layer thickness reproducibly obtainable with our current technology is down to 6 nm, while the dielectric layer can be as low as 4 nm. During the talk we will present our approach for obtaining Au layers with better optical properties than the standard techniques. This is achievable by using an adhesion layer whose influence of the metallic properties is lower than the one of the classical Cr or Ti adhesion layers. These organic adhesion layers behave as dielectrics and thus do not contribute more to the metallic response. Since the imaginary part of permittivity of these layers is negligible and the real part is very close to the silica one, their contribution to the behaviour of the HMMs is minimal. The optical properties of Au with organic adhesion layers showing a closer to theory response than Au with metallic adhesion layer as well as a possible explanation for this behaviour will be presented. This technique can be further used to obtain metal-dielectric multi-layers that lead to HMMs behaviour. Both fabrication possibilities and optical characterisation will be shown and discussed during the talk.
关键词： Au layers optical properties,hyperbolic metamaterials,ultra-thin Au layers
更新于2025-09-23 15:22:29
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Estimation of the lateral dimensions of epitaxial submonolayer CdSe/ZnSe quantum dots
摘要： CdSe fractional monolayer quantum dots (FMQDs) embedded in a ZnSe matrix were produced by atomic layer epitaxy with a nominal coverage of 0.5 monolayer. They have a thickness of a/2, where a is the strained perpendicular lattice constant of cubic CdSe. Their photoluminescence spectra at low temperature exhibit narrow and intense excitonic emission around 2.759 eV. Based on the experimental excitonic emission energy and applying the factorized-envelope approximation, we have estimated that the lateral dimensions of these FMQDs are around 4 - 5 nm and their density is ~ 3 × 1012 cm-2.
关键词： quantum dots size,fractional monolayer quantum dots,epitaxial quantum dots,submonolayer quantum dots,ultra-thin quantum dots,CdSe quantum dots
更新于2025-09-23 15:21:01
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[IEEE 2019 Joint International EUROSOI Workshop and International Conference on Ultimate Integration on Silicon (EUROSOI-ULIS) - Grenoble, France (2019.4.1-2019.4.3)] 2019 Joint International EUROSOI Workshop and International Conference on Ultimate Integration on Silicon (EUROSOI-ULIS) - InAs Electron-Hole Bilayer LED
摘要： We report a novel switched-mode light-emitting device (LED) in an undoped ultra-thin body (UTB) InAs channel based on the electrostatically induced electron-hole (EH) bilayer concept. The induced EH channels at their respective gate interfaces, which remain spatially separated in steady state, gradually diffuse and recombine during a switch-off transient. Using TCAD simulations, we show that continuous switching of the gates with a ～ 12 μs time period leads to radiative recombination of the induced charge carriers with a peak internal quantum ef?ciency (IQE) as high as ～ 92%. The proposed concept obviates the need for chemically doped p-n junctions in the UTB device for light emitting applications and could also be employed for other direct bandgap semiconductors. However, the switching speed is ultimately limited by the thermal generation time.
关键词： ultra-thin body,thermal generation,light emission,Electrostatic doping,III-V on-insulator
更新于2025-09-23 15:21:01
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An Efficient Ultra-Flexible Photo-Charging System Integrating Organic Photovoltaics and Supercapacitors
摘要： Flexible and biocompatible integrated photo-charging devices consisting of photovoltaic cells and energy storage units can provide an independent power supply for next-generation wearable electronics or biomedical devices. However, current flexible integrated devices exhibit low total energy conversion and storage efficiency and large device thickness, hindering their applicability towards efficient and stable self-powered systems. Here, a highly efficient and ultra-thin photo-charging device with a total efficiency approaching 6% and a thickness below 50 μm is reported, prepared by integrating 3-μm-thick organic photovoltaics on 40 μm-thick carbon nanotube/polymer-based supercapacitors. This flexible photo-charging capacitor delivers much higher performance compared with previous reports by tuning the electrochemical properties of the composite electrodes, which reduce the device thickness to 1/8 while improving the total efficiency by 15%. The devices also exhibit a superior operational stability (over 96% efficiency retention after 100 charge/discharge cycles for one week) and mechanical robustness (94.66% efficiency retention after 5000 times bending at a radius of around 2 mm), providing a high-power and long-term operational energy source for flexible and wearable electronics.
关键词： ultra-thin design,photo-charging-capacitors,flexible devices,integration
更新于2025-09-23 15:21:01
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Perovskite Photovoltaics on Roll-To-Roll Coated Ultra-thin Glass as Flexible High-Efficiency Indoor Power Generators
摘要： Indoor perovskite photovoltaics can help power the internet of things revolution, being highly ef?cient, low-cost, printable, and compatible with ?exible substrates. Castro-Hermosa et al. develop ?exible perovskite cells on roll-to-roll coated ultra-thin glass with excellent optoelectrical and mechanical properties, delivering ef?ciencies of 20.6%–22.6% under 200–400 lx LED illumination.
关键词： Flexible high-efficiency indoor power generators,Perovskite photovoltaics,LED illumination,Roll-to-roll coated ultra-thin glass
更新于2025-09-23 15:21:01
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SET Sensitivity of Tri-Gate Silicon Nanowire Field-Effect Transistors
摘要： The SET response of SOI tri-gate silicon nanowires is investigated using direct measurements of current transients. Resulting collected charge distributions are compared to simulations in two steps: Monte-Carlo simulations of deposited energy and TCAD simulation of collected charge, using detailed description of charge generation. Good agreement with experimental data is obtained. Current simulation tools can thus be used, with minor optimization, to simulate such integrated devices. The analysis of SETs show collected charge values lower than both the charge estimated from the LET and the charge actually generated in the nanowire, revealing a limited sensitivity of nanowire devices to high LET ions.
关键词： Nanowire,SEE,Single-Event Transient,Ultra-Thin SOI,Particle-matter interaction,Single-Event Effect,Geant4,FinFET,TCAD,Multiple-gate,Simulation,SET,Experiments
更新于2025-09-23 15:21:01
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Laser Induced Backward Transfer of ultra-thin metal structures
摘要： Ultra-thin, flexible and stretchable interfaces comprising thin metal films and polymers are attracting increasing interest for applications in sensors and optoelectronics. The transfer of ultra-thin gold films for the digital fabrication of such interfaces was investigated in this study using the Laser-Induced Backward Transfer (LIBT) technique. In particular, the transfer of thin and ultra-thin gold films (60, 10 and 5 nm thick) on Polydimethylosiloxane substrate has been achieved using ps pulses and low laser fluences for controllable material transfer. As the size of the nanograins comprising the Au films decreases, their melting point also decreases, enabling the transfer of intact disk-shaped Au nanostructures at low laser fluence values, with form factors and thickness equal to the pristine films. Moreover, the contribution of the substrate has been clarified: the two substrates (silicon, glass) which were used in this work, have significantly different reflectivity to the selected laser wavelength (532 nm), which can considerably influence the thickness and the quality of the transferred disk. The results presented in this work clearly demonstrate the compatibility of LIBT with ultra-thin metal film/ polymer interfaces and highlight the potential application of this digital process for a variety of optoelectronic applications.
关键词： ultra-thin films,Laser Induced Backward Transfer,metal/ polymer interface,short pulsed heating,nanostructures
更新于2025-09-23 15:19:57