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Study of the depletion depth in a frontside biased CMOS pixel sensors
摘要： Depletion of the sensitive volume for semiconductor based detectors is a key to achieve high performance. It is for instance required for charged particle detection in highly radiative environment and for X-ray spectroscopy. PIPPER-2 is a CMOS pixel sensor featuring an architecture that allows the application of the reverse bias of the pn junction from the frontside (cathode), on the electronic side, without process modification. Biasing voltages up to 45 V have been applied to sensor prototypes fabricated on two different high resistivity substrates: a thin epitaxial layer (1 kW cm) and a 40 μm thick bulk substrate (600 W cm). Calculations from a simplified analytical model and 3D-TCAD simulations were conducted to predict the evolution of the depletion depth with the bias voltage. These expectations were compared to measurements of PIPPER-2 illuminated with two X-ray energies. We conclude that the frontside biasing method allows the full-depletion of the thin epitaxial layer. In contrast, depletion of the bulk substrate reaches about half-depth but X-rays are still detected over the full depth.
关键词： X-ray detectors,Particle tracking detectors (Solid-state detectors)
更新于2025-09-23 15:22:29
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Visible light photocatalytic dye decomposition behaviour of solid state reaction grown Zn <sub/>2</sub> TiO <sub/>4</sub> nanoparticles
摘要： In this investigation, visible photocatalytic dye decomposition is carried out with compound semiconductor nanoparticles of zinc orthotitanate (Zn2TiO4). These nanoparticles were grown by the solid state reaction method and characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, photoluminescence study, and Brunauer–Emmett–Teller (BET) study. The BET surface area of the Zn2TiO4 nanoparticles was found to be 8.78 m2/g. The photocatalytic activity is carried out by using a 500 W halogen light source having a spectrum in the range of 450 to 860 nm and the reaction kinetics was found to be the pseudo first order. The reaction rate constant was found to be 0.069 min?1. Discussion is given on the possible mechanism of the observed visible photocatalytic dye decomposition activity. The cost of the material used is very low, so it could be very useful for visible photocatalytic dye decomposition.
关键词： visible photocatalysis,zinc orthotitanate,solid state reaction,dye decomposition,nanoparticles
更新于2025-09-23 15:22:29
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Characterization of ECR plasma by means of radial and axial X-ray diagnostics
摘要： This work presents the X-ray characterization of the plasma generated in a simple mirror axis symmetric trap as a function of the magnetic field profile. A Si-Pin detector has been used to characterize warm electron population in axial and radial directions at 6.83 GHz. Moreover, the hot electrons emitted in axial direction has been measured by means of a HyperPure Germanium (HpGe) detector. Results show that X-ray emission is not homogenous, and its homogeneity and temperature depend strongly on the magnetic field profile, and especially on the Bmin/BECR ratio.
关键词： Ion sources (positive ions, negative ions, electron cyclotron resonance (ECR), electron beam (EBIS)),Solid state detectors,X-ray detectors
更新于2025-09-23 15:22:29
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[IEEE 2018 International Flexible Electronics Technology Conference (IFETC) - Ottawa, ON, Canada (2018.8.7-2018.8.9)] 2018 International Flexible Electronics Technology Conference (IFETC) - Sustainable Materials for Solid Flexible Supercapacitors
摘要： Solid, thin and flexible supercapacitors have been investigated leveraging sustainable and low-cost biomass-based carbon electrodes and a series of solid polymer electrolytes. The performance of these solid flexible devices was systematically compared to commercial activated carbon (AC) and liquid electrolyte baseline. Solid-state devices especially chitosan AC enabled supercapacitors were shown to closely resemble the highly capacitive behavior and high rate performance of their liquid counterparts. This demonstrates that high surface area, intricately porous activated carbon networks can still be readily accessible to polymer electrolytes, which is important to the transition of supercapacitor devices from liquid to solid-state. These materials and systems represent simple, sustainable and cost-effective approaches for next-generation solid thin, flexible energy storage devices.
关键词： polymer electrolytes,supercapacitor,solid-state,thin and flexible
更新于2025-09-23 15:22:29
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A novel Nd <sup>3+</sup> -doped MgO-Al <sub/>2</sub> O <sub/>3</sub> -SiO <sub/>2</sub> -based transparent glass-ceramics: towards excellent fluorescence properties
摘要： Generally, glass-ceramics have superior properties compared to their parent glasses. Here, we prepared a novel Nd3+-doped MgO-Al2O3-SiO2-based transparent glass-ceramics with excellent fluorescence properties. The effects of Nd2O3 content on the structure and properties of glass-ceramics were studied, aiming to provide a key guidance for preparing this transparent glass-ceramics. The results revealed that the glass stability increased originally and then decreased with increasing Nd2O3 content, so did the variation of wavenumbers in infrared spectra. And these glass-ceramics are mainly composed of cordierite with residual glassy phase. The three phenomenological intensity parameters (Ω2,4,6) and radiative properties were estimated by Judd-Ofelt theory, and the values of Ω2 first decreased and then increased with increasing Nd2O3 content. Three main emission peaks ascribed to the transitions from 4F3/2 to 4I9/2, 4I11/2, 4I13/2 at 898, 1057, 1330 nm were observed, respectively. The branching ratios for 4F3/2→4I11/2 transition increased as the Nd2O3 content raised, and the fluorescence lifetimes of the 4F3/2 level were found to increase first and then decrease with Nd2O3 content (from 181 to 726 μs). The excellent fluorescence properties indicate that this novel glass-ceramics can be used as a potential solid-state optical functional material for 1.06 μm laser emission.
关键词： MgO-Al2O3-SiO2,Judd-Ofelt theory,Nd3+-doped,Transparent glass-ceramics,Solid-state optical functional materials
更新于2025-09-23 15:22:29
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Counter Anion Effect on the Photophysical Properties of Emissive Indolizine-Cyanine Dyes in Solution and Solid State
摘要： Near-infrared emissive materials with tunable Stokes shifts and solid-state emissions are needed for several active research areas and applications. To aid in addressing this need, a series of indolizine-cyanine compounds varying only the anions based on size, dipole, and hydrophilicity were prepared. The effect of the non-covalently bound anions on the absorption and emission properties of identical π-system indolizine-cyanine compounds were measured in solution and as thin films. Interestingly, the anion choice has a significant influence on the Stokes shift and molar absorptivities of the dyes in solution. In the solid-state, the anion choice was found to have an effect on the formation of aggregate states with higher energy absorptions than the parent monomer compound. The dyes were found to be emissive in the NIR region, with emissions peaking at near 900 nm for specific solvent and anion selections.
关键词： solid-state emission,optical materials,NIR emissive materials,indolizine cyanine,stokes shift
更新于2025-09-23 15:22:29
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Synthesis and mechanoluminescent property of (Eu2+, Dy3+)-co-doped strontium aluminate phosphor by soft mechanochemistry-assisted solid-state method
摘要： (Eu2+, Dy3+)-co-doped strontium aluminate (SrAl2O4:Eu2+, Dy3+) powder as a mechanoluminescent (ML) phosphor was synthesized via soft mechanochemical pretreatment of precursor mixtures in a stirred media mill and subsequent calcination. Effect of soft mechanochemical pretreatment of precursors on the synthesis process as well as the photoluminescent (PL) and ML properties of SrAl2O4:Eu2+, Dy3+ phosphor was investigated. The precursor mixtures unground and ground at different time and the resultant phosphors were characterized by laser particle size analysis, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, Fourier transfer infrared spectroscopy and optical property measurement. The results reveal that soft mechanochemical pretreatment of precursor mixture promotes the crystal growth, and reduces the subsequent calcination temperature. SrAl2O4:Eu2+, Dy3+ phosphor can be obtained via calcining at 1200 oC for precursor mixture ground at 60 min, but formed via calcining at 1400 oC for unground precursor mixture. The phosphor synthesized with precursor mixture ground at 60 min has the maximum PL and ML intensities due to the enhancement of Eu2+ and Dy3+ ions into the crystal lattice to form more electron traps. The measurements by a designed ML instrument indicate that the ML intensity increases with increasing impact stress, and decreases with multiple applications of the same impact stress on phosphor disks.
关键词： Phosphor,Soft mechanochemistry,(Eu2+, Dy3+)-co-doped strontium aluminate,Solid-state method,Mechanoluminescence
更新于2025-09-23 15:22:29
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Rivalry Under Pressure - The Coexistence of Ambient-pressure Motifs and Close-packing in Silicon Phosphorus Nitride Imide SiP2N4NH
摘要： Non-metal nitrides such as BN, Si3N4 and P3N5 meet numerous demands on high-performance materials and their high-pressure polymorphs exhibit outstanding mechanical properties. Herein, we present the silicon phosphorus nitride imide SiP2N4NH featuring six-fold coordinated Si. Using the multianvil technique, SiP2N4NH was obtained from high-pressure high-temperature synthesis at 8 GPa and 1100 °C with in situ formed HCl acting as a mineralizer. Its structure was elucidated by combination of single-crystal X-ray diffraction and solid-state NMR measurements. Moreover, SiP2N4NH was characterized by energy-dispersive X-ray spectroscopy and (temperature-dependent) powder X-ray diffraction. The highly condensed Si/P/N framework features PN4 tetrahedra as well as the rare motif of SiN6 octahedra and is discussed in the context of ambient-pressure motifs competing with close-packing of nitride anions, representing a missing link in high-pressure chemistry of non-metal nitrides.
关键词： nitrides,silicon,high-pressure chemistry,phosphorus,solid-state structures
更新于2025-09-23 15:22:29
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Lab and test beam results of irradiated silicon sensors with modified ATLAS pixel implantations
摘要： In Dortmund, planar silicon pixel sensors were designed with modified n+-implantations and produced in n+-in-n sensor technology. Baseline for these new designs was the layout of the IBL planar silicon pixel sensor with a 250 μm × 50 μm pitch. The different implantation shapes are intended to cause electrical field strength maxima to increase charge collection after irradiation and thus increase particle detection efficiency. To test and compare the different pixel designs, the modified pixel designs and the standard IBL design are placed on one sensor which can be read out by a FE-I4. After irradiation with protons and neutrons respectively the performance of several sensors is tested in laboratory and test beam measurements. The presented laboratory results verify that all sensors are fully functional after irradiation. The the test beam measurements show different results for sensors irradiated to the same fluence with neutrons in Sandia compared to sensors irradiated with neutrons in Ljubljana or with protons at CERN PS.
关键词： Particle tracking detectors (Solid-state detectors),Radiation-hard detectors,Particle tracking detectors,Solid state detectors
更新于2025-09-23 15:21:21
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Particularities of trichloroethylene photocatalytic degradation over crystalline RbLaTa2O7 nanowire bundles grown by solid-state synthesis route
摘要： This is the first report on synthesis and photocatalytic activity for trichloroethylene (TCE) degradation under simulated solar light over RbLaTa2O7 layered perovskites with predominant nanowire or platelet morphologies. SEM images witnessed that the one step thermal treatment at 1200 °C lead to formation of RbLaTa2O7 nanowires with diameter of 80~320 nm and several microns in length associated in bundles and sharp-edged, merged platelets (minor phase). The two-step annealing at 950 °C and 1200 °C resulted in decrease of wires bundle population and increase in that of platelets merged in facetted particles. The RbLaTa2O7 nanowires are made of by well-aligned atomic rows with preferred orientation toward the c-axis, relatively free of defect. High density of hydroxyl groups on the sample calcined in mild conditions (RbLaTa_01) favors the photo mineralization of TCE. In contrast, the activity of RbLaTa_02 annealed in harsh conditions (950 and 1200 oC), poor in surface hydroxyl groups, remained modest. The weak surface basicity directed the reaction mainly to generation of intermediate chlorinated compounds. Pd and Au were supported on RbLaTa2O7 perovskites as an alternative strategy to boost the removal of chlorinated pollutants by combining photocatalytic (mineralization) and catalytic (hydrodechlorination, HDC) processes. The mineralization of TCE to Cl- was drastically hindered in presence of methanol due to quenching of ?OH radicals by alcohol. The results suggested that the density of RbLaTa2O7 surface hydroxyl groups is essential for photo mineralization of TCE whereas the surface carbonate is beneficial for the formation of intermediate chlorinated product.
关键词： solid state reaction,layered perovskites,trichloroethylene,simulated solar light,photocatalysis
更新于2025-09-23 15:21:21