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A newly designed, 100 mm2, silicon drift detector has been installed on an aberration-corrected scanning transmission electron microscope equipped with an ultra-high resolution pole piece, without requiring column modifications. With its unique, windowless design, the detector's active region is in close proximity to the sample, resulting in a dramatic increase in count rate, while demonstrating an increased sensitivity to low energy X-rays and a muted tilt dependence. Numerous examples of X-ray energy dispersive spectrometry are presented on relevant materials such as Al x Ga1-x N nanowires, perovskite oxides, and polycrystalline CdTe thin films, across both varying length scales and accelerating voltages.
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http://dx.doi.org/10.1017/S1431927614001639 | DOI Listing |
Nucl Instrum Methods Phys Res A
March 2025
Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
x-ray fluorescence (XRF) photons induced from gold nanoparticles (GNPs) after being irradiated by an x-ray beam allow for highly sensitive XRF imaging/computed tomography (XFCT) of biological samples containing GNPs at low concentrations on the order of parts-per-million (ppm). The primary goal of this Monte Carlo (MC) study was to investigate the feasibility of upgrading an existing experimental benchtop XRF/XFCT imaging setup adopting a single silicon drift detector (SDD), developed based on the aforementioned concept (often known as XFCT), by deploying another SDD within the same setup. Specifically, an MC model of the original single SDD XFCT setup, along with a filtered 62 kVp polychromatic x-ray beam, was developed using the Geant4 MC toolkit, and added with a second SDD at an equidistance of 11 cm from the isocenter on the opposite side.
View Article and Find Full Text PDFMicromachines (Basel)
August 2025
School of Integrated Circuits, Tsinghua University, Beijing 100084, China.
In this paper, a novel 4H-SiC LDMOS structure with a trench heterojunction in the source (referred as to THD-LDMOS) is proposed and investigated for the first time, to enhance the reverse recovery performance of its parasitic diode. Compared with 4H-SiC, silicon has a smaller band energy, which results in a lower built-in potential for the junction formed by P+ polysilicon and a 4N-SiC N-drift region. A trench P+ polysilicon is introduced in the source side, forming a heterojunction with the N-drift region, and this heterojunction is unipolar and connected in parallel with the body PiN diode.
View Article and Find Full Text PDFACS Meas Sci Au
August 2025
Institute of Chemical Technologies and Analytics, TU Wien, 1060 Vienna, Austria.
Extracellular vesicles (EVs) are nanosized particles that are associated with various physiological and pathological functions. They play a key role in intercell communication and are used as transport vehicles for various cell components. In human milk, EVs are believed to be important for the development of acquired immunity.
View Article and Find Full Text PDFNanomaterials (Basel)
July 2025
Institute for Applied Physics and Measurement Technology, University of the Bundeswehr Munich, 85579 Munich, Germany.
This work investigates the impact of an internal electric field on the annihilation characteristics of positrons implanted in a 180(10)nm SiO layer of a Metal-Oxide-Silicon (MOS) capacitor, using Positron Annihilation Lifetime Spectroscopy (PALS). By varying the gate voltage, electric fields up to 1.72MV/cm were applied.
View Article and Find Full Text PDFWe present the design, modeling, and optimization of high-performance plasmonic electro-optic modulators based on indium tin oxide (ITO), leveraging voltage-gated carrier density modulation. The carrier density is modeled using the classical drift-diffusion (CDD) and nonlinear Schrödinger-Poisson coupling (SPC) methods, with the latter providing precise carrier distribution profiles, particularly in epsilon-near-zero (ENZ) media like ITO. By combining the nanoscale field confinement of surface plasmon polaritons with the ENZ effect, our modulators, integrated with silicon waveguides and optimized for operation at = 1550 nm, achieve a 3-dB bandwidth of 210 GHz, an insertion loss of 3 dB, and an extinction ratio of 5 dB for a device length of under 4 µm.
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