Si Strip Research Articles

Effect of Roll Diameter on Temperature of Aluminum Alloy Strip during Casting Using a Vertical Type High Speed Twin Roll Caster

The temperature of an aluminum alloy (Al-6%Si) strip cast using a vertical-type high-speed twin-roll caster was measured by inserting a K-type thermocouple into the strip. The effects of the roll diameter on supercooling, cooling rate, and temperature at the roll bite were investigated. It was found that the roll diameter affects the cooling condition of the strip. The thickness of the thermocouple was 0.1 mm and the sampling rate was 100 Hz. Copper rolls with diameters of 300 and 600 mm, respectively, were used. The roll width was 100 mm and the roll speed was 30 m/min. The roll load was 5 or 20 kN.

Microstructure of Al-2%Si and Al-6%Si Strips Cast Using Vertical-Type High-Speed Twin-Roll Caster

Al-2%Si and Al-6%Si were cast at a roll speed of 30 m/min and a roll load of 5 N/mm using a vertical-type high-speed twin-roll caster. The rolls were suddenly stopped during casting and the molten metal was solidified. The effect of Si content on the microstructure at the cross section near the roll bite was investigated using Weck’s reagent. The cross section of the Al-2%Si strip consisted of five layers (one center layer, two middle layers, and two surface layers) at the roll bite and that of the Al-6%Si strip consisted of three layers (one center layer and two side layers). The a-Al in the center layer was globular for both Al-2%Si and Al-6%Si. The relative thickness of the center layer for Al-6%Si was greater than that for Al-2%Si. In Al-2%Si, the surface layer had a very fine chill-zone microstructure. The Si solid-solution content in the α-Al in the surface layers and the center layer was less than that in the middle layers in the Al-2%Si strip.

Controlling the Modal Confinement in Silicon Nanophotonic Waveguides through Dual‐Metamaterial Engineering

AbstractFlexible control of the modal confinement in silicon photonic waveguides is an appealing feature for many applications, including sensing and hybrid integration of active materials. In most cases, strip waveguides are the preferred solution to maximize the light interaction with the waveguide surroundings. However, the only two degrees of freedom in Si strip waveguides are the width and thickness, resulting in limited flexibility in evanescent field control. Here, a new strategy that exploits metamaterial engineering of the waveguide core and cladding is proposed and demonstrated to control the index contrast in the vertical and horizontal directions, independently. The proposed dual‐material geometry yields a substantially increased calculated bulk sensitivity in the air (0.35 RIU [refractive index unit]/RIU) compared to the best case scenario for a strip waveguide (0.3 RIU/RIU). To experimentally demonstrate the potential of this approach, dual‐metamaterial ring resonators operating with the transverse‐magnetic polarized mode in 220‐nm‐thick waveguides with air as upper‐cladding are implemented. Micro‐ring resonators implemented with strip and dual‐metamaterial waveguides exhibit the same measured quality factors, near 30 000. Having similar measured quality factors and better calculated bulk sensitivity than strip waveguides, the proposed dual‐metamaterial geometry stands as a promising approach to control modal confinement in silicon waveguides.

TCAD simulation of radiation hard n-MCz and n-Fz Si microstrip detector for the HL-LHC

A radiation hard Si detector is used in the new CMS tracker detector at HL-LHC. It has been observed that n-MCz and n-Fz Si as a material can be used for the Si micro strip detector. The detector design for this material should be simulated and optimized to get high CCE. In order to understand the charge collection behavior of the n-MCz/n-FzSi detector, it is required to simulate and compare the radiation damage effects in the mixed irradiated n-MCz Si and proton irradiated n-Fz Si micro strip detector equipped with metal overhang and multiple guard rings. In this paper, we have done analysis and optimization of the radiation hard n-MCz Si/n-Fz Si strip detector design for the HL-LHC experiment in order to get high CCE.

Investigation of mixed irradiation effects in p-MCz thin silicon microstrip detector for the HL-LHC experiments

A lot of R&D work is carried out in the CERN RD 50 collaboration to find out the best material for the Si detectors that can be used in the harsh radiation environment of HL-LHC, n and p-MCz Si was identified as one of the prime candidates as a material for strip detector that can be chosen for the phase 2 upgrade plan of the new Compact Muon Solenoid Tracker detector in 2026. In this work, four level deep-trap mixed irradiation model for p-MCz Si is proposed by the comparison of experimental data on the full depletion voltage and leakage current to the Shockley Read Hall recombination statistics results on the mixed irradiated p-MCz Si PAD detector. The effective introduction rate (η eff) of shallower donor deep trap E30K is extracted using SRH theory calculations for experimental N eff and that can show the behavior of space charges and electric field distribution in the p-MCz Si strip detector and compared its value with the η eff of shallower donor deep trap E30K in the nMCz Si microstrip detector. Prediction uncertainty in the p-MCz Si radiation damage mixed irradiation model is considered in the full depletion voltage and leakage current. A very good agreement is observed in the experimental and SRH results. This radiation damage model is also used to extrapolate the value of the full depletion voltage at different mixed (proton + neutron) higher irradiation fluences for the thin p-MCz Si microstrip detector.

Macroscopic flexotronics enhanced controllable piezotronic-like response by flexual semiconductor devices

Interface engineering to modulate electronic transport is a pivotal technological and scientific endeavour. Herein, regardless of the macroscopic or microscopic aspects, we successfully demonstrate the piezotronic-like response in bulk bending centrosymmetric semiconductors single crystal Si strip with more flexibility and flexure in the home-built fixed platform. The flexoelectric potential and flexotronics could be dramatically enhanced by bending single crystal Si strip due to the change of the crystal structure and lattice constant. Besides, the flexoelectric polarization direction can be tuned by changing the bending direction. Moreover, the thinner the bending material is, the greater the SBH change rate. Theoretically, the working mechanism of flexoelectricity induced by the synergistic contribution consequence of the surface piezoelectric effect and bulk flexoelectric effect is elucidated.

Characterization of the Fe-6.5wt%Si Strip with Rapid Cooling Coupling Deep Supercooled Solidification.

The phase transition law between ordered and disordered phases, second phase reinforcement, microstructure, and mechanical properties were systematically studied in the rapid cooling coupling deep supercooled solidification process through an arc melting furnace, electromagnetic induction heating, and high-speed cooling single-roll technology. The results show that uniform nucleation and grain refinement are promoted under rapid cooling coupling deep supercooled solidification, and the phase transition from the disordered phase (A2) to the ordered phase (B2 and DO3) is also effectively suppressed. The decreased crystalline grain size and optimized microstructure morphology improved the plasticity and magnetic property. The Fe-6.5wt%Si steel strip at 42 m/s has a good phase composition of Fe (predominant), Fe2Si, and SiC. The sample showed an equiaxed ferrite crystal structure, and the saturation magnetizations were 302.5 and 356.6 emu/g in the parallel magnetic direction and the vertical magnetic direction, respectively. This phase transition behavior contributed to the exceptional magnetic property of the Fe-6.5wt%Si steel.

Generalized surface morphology model for Si photonic waveguide simulation

A generalized surface morphology model is presented and validated to more effectively simulate the effects of surface variations (e.g., surface roughness and local thickness variations) on integrated Si photonic waveguides. To demonstrate the validity of this approach, a variety of surface roughness morphologies generated using this model are incorporated within a commercial finite-difference-time domain (FDTD) modeling package to simulate waveguide loss in Si strip optical waveguide geometries typically encountered in Si-based photonic integrated circuits. The FDTD simulation results are in very good agreement with the Payne and Lacey theoretical model for radiation-mode scattering loss based on surface correlation functions for RMS roughness values exceeding 2 to 3 nm where such scattering dominates. This agreement validates the efficacy of the generalized surface morphology model and its use for investigating the effects of irregular surface variations on photonic device performance.

Equatorial aberration for powder diffraction data collected by continuous-scan integration of a silicon strip X-ray detector

The application of continuous-scan integration to collect X-ray diffraction data with a Si strip X-ray detector (CSI-SSXD) introduces additional effects on the peak shift and deformation of peak shape caused by the equatorial aberration. A deconvolutional method to correct the effects of equatorial aberration in CSI-SSXD data is proposed in this study. There are four critical angles related to the effects of spillover of the incident X-ray beam from the specimen face in the CSI-SSXD data. Exact values of cumulants of the equatorial aberration function are efficiently evaluated by 4 × 4 point two-dimensional Gauss–Legendre integral. A naïve two-step deconvolutional method has been applied to remove the effects of the first and third-order cumulants of the equatorial aberration function from the observed CSI-SSXD data. The performance of the algorithm has been tested by analyses of CSI-SSXD data of three LaB6 powder specimens with the widths of 20, 10, and 5 mm, collected with a diffractometer with the goniometer radius of 150 mm.

Effects of Nozzle and Roll on Surface Condition of Al-1%Si Strip Cast Using Vertical type High Speed Twin Roll Caster

When a strip of Al-Si alloy with an Si content of 1% was cast using a vertical-type high-speed twin-roll caster, cracks form in its surface. The effects of the pouring method, the shape and position of the nozzle, and the roll surface texture on surface crack formation were evaluated with a roll caster. The rolls were made of a copper alloy, and the roll speed was 30 m/min. The as-cast strips were bent to investigate the degree of crack formation, and the outer surface of the strips was observed without magnification and with a stereomicroscope to determine the influence of the pouring method, the shape and position of the nozzle, and the roll surface. A roll machined to form V-shaped grooves 0.4 mm deep on the surface of the strips was most useful for reducing surface cracking. Changing the shape of the nozzle tip was second-most effective. There was a clear correlation between the roll surface condition and surface cracking in the Al-Si strip.

34.2: Invited Paper: High performance single crystal Si TFTs fabricated on single crystal Si strip formed by micro‐chevron laser beam scanning

34.2: <i>Invited Paper:</i> High performance single crystal Si TFTs fabricated on single crystal Si strip formed by micro‐chevron laser beam scanning

Applying crystallographic orientation analysis for exploring deformation mechanism of 6.5 wt.% Si electrical strip during twin-roll thin strip casting process

The study described here is aimed at illuminating deformation mechanism involved in Twin-roll Thin Strip Casting Process (TRSC) with respect to high-permeability 6.5 wt.% Si electrical strip (6.5 wt.% Si strip) in terms of crystal plasticity (CP) theory, and a Visco-plastic Self-consistent model (VPSC) was utilized to explore the deformation mechanism by applying crystallographic orientation (OR) analysis. Results underscore that the activation of overall potential single slip system with regard to studied 6.5 wt.% Si strip including { 110 } < 111 > , { 112 } < 111 > as well as { 123 } < 111 > can contribute to the OR conversion from Cube texture to Rotated-Cube texture, α-fiber texture as well as γ-fiber texture, while with different evolution rate during deformation. The potential multi-slip system of { 112 } < 111 > + { 123 } < 111 > with average number of activated slip system per grain ~9.1–9.4, and multi-slip system of { 110 } < 111 > + { 112 } < 111 > + { 123 } < 111 > with average number of activated slip system per grain ~10.4–10.8 are identified to be the predominant slip systems during deformation by comparing to the actual OR features obtained from TRSC-processed 6.5 wt.% Si strip. The CP-based method proposed in present study is deemed as a reference to investigate deformation behavior involved in the other semi-solid forming process.

A novel strip-slot-strip waveguide with extremely high dispersion and large bandwidth using cascaded resonant coupling

In this study, a novel strip-slot-strip hybrid waveguide was proposed for extremely high dispersion and large bandwidth. An extremely high dispersion was produced using a strong cascaded coupling effect among strip, slot, and strip waveguide modes. The properties were numerically analysed using the finite difference time-domain (FDTD) method. The results indicated that a high normal dispersion of −1.9412 × 105 ps/km-nm with a full width at half maximum (FWHM) of 33.6 nm around a wavelength of 2005 nm was obtained. The centre wavelength, peak value, or bandwidth of the dispersion curve could be adjusted by changing the thicknesses of the Si and Si3N4 strips, the separation of the Si strip and slot, and the separation of the slot and Si3N4 strip simultaneously. The two strip thicknesses, two separations, and entire structure’s width could be used to change the proposed structure’s aspect ratio. The performance of the proposed structure was compared to some existing structures.

Roll Casting of Al-Mg-Si Alloy

The aluminum alloy Al–5%Mg–2%Si, the chemical content of which is close to that of the Magsimal-59 aluminum alloy commonly for die casting, was successfully cast into strips using a vertical high-speed twin-roll caster at a speed of 30 m/min. This means that Al–5%Mg–2%Si is suitable for the high-speed twin roll-casting. The as-cast Al–5%Mg–2%Si strip was then successfully cold-rolled to a thickness of 0.7 mm. Tension and cup tests were conducted on the cold-rolled annealed strips. The tensile stress was 205 MPa and the elongation was 20% for a thickness of 1 mm. The limiting drawing ratio was 2.0 at a 0.7 mm thickness. The present results demonstrates that Al–5%Mg–2%Si can be used for die casting and sheet forming. This means that use of this alloy for both sheet forming and die casting could eliminate the need for the separation of wrought aluminum alloys from cast aluminum prior to processing at recycling plants.

Development of Si Beam Position Detectors for NA61/SHINE experiment

The NA61/SHINE experiment at the CERN SPS is undergoing a major upgrade during the LHC Long Shutdown 2 period (2019-2021). The upgrade is essential to fulfil the requirements of the new open charm measurement program. In this program detector will operate at a beam intensity increased by a factor of 10, which requires an upgrade of current Beam Position Detectors (BPDs). New BPDs should monitor lead and proton beam intensities with up to 105 Hz rate. In this paper, progress on design and development of the new BPDs based on Si strip detectors, its front-end and readout electronics, as well as integration with the NA61/SHINE DAQ is presented.

Rectangular Maxwell’s fisheye lens via transformation optics as a crossing medium for dissimilar waveguides

Different material platforms, each offering a set of unique advantages, have been introduced for photonic integrated circuits. These platforms may be used in the same photonic chip to explore their advantages. Consequently, the in-plane crossing of dissimilar waveguides may be inevitable. In this paper, we investigate, for the first time to our knowledge, the crossing of silicon nitride ( S i 3 N 4 ) and silicon (Si) strip waveguides. Recently, the imaging property of the Maxwell’s fisheye lens has been exploited to design waveguide crossings. However, the refractive indices of S i 3 N 4 and Si are different by about 1.45, so the crossing medium should have different refractive indices at its edges to minimize reflection from the interface of the waveguide and the crossing medium. We utilize quasi-conformal transformation optics to design a rectangular Maxwell’s fisheye lens as a crossing medium of S i 3 N 4 and Si strip waveguides. We implement the rectangular lens with graded photonic crystal and numerically evaluate the performance of the designed waveguide crossing.

High performance thin-film transistors fabricated on a single crystal Si strip by micro-chevron laser beam scanning method

High performance and uniform thin-film transistors were fabricated on a grain-boundary (GB) free single crystal Si strip for the first time. Here sputter-SiO2 gate insulator was used. Electron mobility μ was 548 cm2 V−1 s−1, subthreshold swing ss was 0.279 V dec−1, and on/off ratio was 2.4 × 107. Variability of ss was only 9.4% but that of μ was 34.2%. Carrier scattering was known to be dominated by GB in conventional polycrystalline Si, but it was dominated by phonon scattering in the GB-free Si strip irrespective of μ value. The μ deviation was shown to be due to crystal orientation variation along channel direction.

Equatorial aberration of powder diffraction data collected with an Si strip X-ray detector by a continuous-scan integration method.

Exact and approximate mathematical formulas of equatorial aberration for powder diffraction data collected with an Si strip X-ray detector in continuous-scan integration mode are presented. An approximate formula is applied to treat the experimental data measured with a commercial powder diffractometer.

Tensile-shear fracture behaviour of resistance spot-welded hot stamping sheet steel with Al–Si coating

ABSTRACT Resistance spot welding (RSW) process with protective coatings on advanced high-strength steels is a challenge. An ultimate tensile strength (UTS)1500 MPa grade hot stamping sheet steel(22MnB5) with Al–Si coating was employed for the RSW process in the present study. The effects of Al–Si coating on the microstructure of RSW joints and tensile-shear fracture behaviour were investigated. Strip-like Fe-(Al,Si) cladding on the surface of nugget tongues acted as the crack source and initiated the fracture. Two types of fatigue failure mode were observed: nugget pull-out with tearing of base material (BM) and eyebrow-shaped fracture along the BM width direction, corresponding to high and low loading levels, respectively. All fatigue fracture cracks were found to be originated along the Fe-(Al,Si) strip through the heat-affected zone.

Detection of the Low Energy Recoil 3He in the Reaction 2H(8He,3He)7H

Investigation of the 7H-system in the experiment conducted at the fragment separator ACCULINNA-2 in the 8He(2H,3He)7H reaction requires to detect the recoil 3He ions with energy down to 6 MeV. For this purpose two $$\Delta E{\text{—}}E$$ particle telescopes are used, with each telescope having in front a thin (20-μm) Si strip detector ($$\Delta E{\text{—}}SSD$$). The maps of thickness heterogeneity of the thin detectors were determined by measuring the energy losses of the 226Ra α-particles. The adopted thickness normalization method provides a good identification of the 3He nuclei being recorded in the presence of a high 4He background. Two approaches were used for calculating the energy losses of the identified 3He and 4He reaction ejectiles and reconstructing their energy values available at the exit from the deuterium target. The developed techniques were applied for the 7H missing-mass reconstruction.