The increasing interest in thin flexible and bendable devices has led to a strong demand for mechanically robust and electrically reliable transparent electrodes. Indium doped Tin Oxide (ITO) and ...Aluminium doped Zinc Oxide (AZO) are among the most employed transparent conductive oxides (TCO) and their reliability on flexible substrates have thus received a great attention. However, a high flexibility is usually achieved at very low thickness, which, unfortunately, compromises the electrical conductivity.
Here we report the effects of mechanical bending cycles on the electrical and optical properties of ultra thin AZO/Ag/AZO multilayers (45nm/10nm/45nm) and, for comparison, of AZO and ITO single layers whose thickness was, in both cases, 100nm and 700nm, deposited at room-temperature on flexible polyethylene naphthalate (PEN) plastic substrates. The electrical stability of the films after several cycles of bending were evaluated by monitoring the relative variation of the electrical resistance with respect to the as prepared sample; the structural damage induced by bending was detected by Scanning Electron Microscopy (SEM). We observed an excellent electrical stability and high flexibility in the AZO/Ag/AZO sample even after 100 cycles, whereas for the single AZO and ITO films the resistivity rapidly increases. The experimental results and numerical simulations provide clear evidences of the key role played by the ductile Ag interlayer that provides improved robustness under mechanical strain.
•Evidence of good electrical quality of AZO/Ag/AZO ultra thin films without thermal annealing.•Evidence of much better flexibility with respect to films of single AZO and ITO with equal or higher thickness.•Evidence of much lower structural damage compared to films of single AZO and ITO with equal thickness upon bending cycles.•Numerical simulation of strain intensity and distribution within the films during mechanical bendings.•Evidence of the possible use of AZO/Ag/AZO ultra thin films as Transparent Conductive Material for flexible thin devices.
In this paper, novel optimization methodologies of sub-relativistic guided interaction structures for dielectric laser particle acceleration (DLA) are presented. In particular, we focus on ...co-propagating geometries based on slot waveguides in continuous wave (CW) operation, where the particle flow and the direction of propagation of the accelerating field are co-linear. Since the velocity of sub-relativistic particles varies along the acceleration path, proper tapering of the waveguide geometry is required to achieve an extended acceleration region, and, thus a large energy gain. The design of an optimal taper ensuring particle-wave synchronicity and maximum energy gain is pursued through a physics-based approach, and these results are compared, for validation, with the outcomes of a downhill simplex method searching algorithm. Additionally, the application of a simplified 2D model of the accelerating slot waveguide is investigated and profitably used to get qualitative results useful for fast structure optimization. Indeed, this approach can hold significant potential for the development of novel accelerating structures, as it enables a thorough and fast exploration of the design space.
Environment friendly, thin and flexible devices require the synthesis of Indium-free new transparent conducting materials (TCM) with improved structural, thermal, electrical and optical properties. ...To overcome the critical issues raised by thinning the TCM, we propose a multilayer structure in which nanogranular Ag film obtained by supersonic cluster beam deposition is sandwiched in between Alluminum doped Zinc Oxide (AZO) thin layers. The introduction of the nanogranular Ag film, when compared to the standard sputtered one, yields higher optical transmittance in the technologically relevant VIS-NIR region and superior mechanical reliability while preserving low electrical resistance. The present results open new perspectives to exploit the nanogranular nature of conductive films, synthesized via Supersonic Cluster Beam Deposition, to engineer transparent conducting materials.
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•Enhancement of the optical transmittance in the visible and IR range.•Low electrical resistivity of the nanogranular Ag film.•High flexibility and electrical reliability during bending.•Validation of experimental results by numerical simulation.•Implementation of nanogranular ultra-thin films as flexible transparent electrode.
Abstract
In this paper we present the numerical design and simulation of RF antennas to be employed in Ion Cyclotron Resonance Heating (ICRH) systems working in ECRIS environment. A 3D full-wave ...numerical model, based on the coupling between COMSOL FEM solution of Maxwell equations and the MATLAB-computed non-homogeneous plasma dielectric tensor, has been employed in order to study the performances of several ICRH antennas. Results in terms of S-parameters, on-axis electric field and RF absorbed power inside the plasma chamber have been obtained and compared between the chosen antenna geometries. The presented study will permit to better understand the fundamental aspects of ion dynamics in ECRISs as well as allowing the design of a proper matching network between the RF amplifier and the antenna, necessary to cope with the plasma properties’ fast variations. Further ion kinetic simulations are ongoing.
Abstract An innovative ECR ion trap facility, called PANDORA (Plasma for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry), was designed for fundamental plasma processes and ...nuclear physics investigations. The overall structure consists of three subsystems: a) a large (70 cm in length, 28 cm in inner diameter) ECR plasma trap with a fully superconducting B-minimum magnetic system (B max = 3.0 T) and an innovative design to host detectors and diagnostic tools; b) an advanced non-invasive plasma multidiagnostics system to locally characterize the plasma thermodynamic properties; c) an array of 14 HPGe detectors. The PANDORA facility is conceived to measure, for the first time, in-plasma β -decaying isotope rates under stellar-like conditions. The experimental approach consists in a direct correlation of plasma parameters and nuclear activity by disentangling - by means of the multidiagnostic system that will work in synergy with the γ-ray array - the photons emitted by the plasma (from microwave to hard X-ray) and γ-rays emitted after the isotope β -decay. In addition to nuclear physics research, fundamental plasma physics studies can be conducted in this unconventional ion source equipped with tens of detection and diagnostic devices (RF polarimeter, optical emission spectroscopy (OES), X-ray imaging, space and time-resolved spectroscopy, RF probes, scope), with relevant implications for R&D of ion sources for accelerator physics and technology. Several studies have already been performed in downsized nowadays operating ECRIS. Stable and turbulent plasma regimes have been described quantitatively, studying the change of plasma morphology, confinement, and dynamics of losses using space resolved X-ray spectroscopy.
A compact dc‐break for ECR ion source @ 18 GHZ Leonardi, O.; Torrisi, G.; Sorbello, G. ...
Microwave and optical technology letters,
December 2018, 2018-12-00, 20181201, Letnik:
60, Številka:
12
Journal Article
Recenzirano
This paper shows simulations and experimental result of a 1.5 kW waveguide DC‐Break designed for the AISHa ion source in commissioning phase at INFN‐LNS.
The DC‐Break was designed to fulfill an ...insulation of 50 kV, power losses lower than 0.5 dB by considering the compactness as key requirement.
