- 标题
- 摘要
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- 实验方案
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Demonstration of 200-, 100-, and 50-$\mu$ m Pitch Resistive AC-Coupled Silicon Detectors (RSD) With 100% Fill-Factor for 4D Particle Tracking
摘要： We designed, produced, and tested RSD (Resistive AC-Coupled Silicon Detectors) devices, an evolution of the standard LGAD (Low-Gain Avalanche Diode) technology where a resistive n-type implant and a coupling dielectric layer have been implemented. The first feature works as a resistive sheet, freezing the multiplied charges, while the second one acts as a capacitive coupling for readout pads. We succeeded in the challenging goal of obtaining very fine pitch (50, 100, and 200 μm) while maintaining the signal waveforms suitable for high timing and 4D-tracking performances, as in the standard LGAD-based devices.
关键词： Silicon detectors,avalanche charge multiplication,LGAD,timing,RSD,4D tracking,AC-coupled readout
更新于2025-09-16 10:30:52
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Analysis and numerical design of Resistive AC-Coupled Silicon Detectors (RSD) for 4D particle tracking
摘要： In this paper we present the numerical simulation of silicon detectors with internal gain as the main tool for 4-dimensional (4D) particle trackers design and optimization. The Low-Gain Avalanche Diode (LGAD) technology and its present limitations are reviewed with the aim of introducing the Resistive AC-Coupled Silicon Detectors (RSD) paradigm as a case study of our investigation. Authors here present Spice-like and 2D/3D Technological Computer-Aided Design (TCAD) simulations to characterize sensors in terms of both their electrostatic behavior, capacitive (dynamic) coupling and radiation-hardness performances, showing the methodological approach used in order to extract the set of layout rules allowing the release of RSD1, the incoming production run at Fondazione Bruno Kessler (FBK) of next-generation silicon detectors for 4D tracking with intrinsic 100% fill-factor.
关键词： Charge multiplication,Fast detectors,Solid-state silicon detectors,TCAD modeling,Particle tracking detectors,Particle timing detectors
更新于2025-09-16 10:30:52
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Carrier Multiplication in PbS Quantum Dots Anchored on a Au Tip using Conductive Atomic Force Microscopy
摘要： Carrier multiplication (CM) is the amplification of the excited carrier density by two times or more when the incident photon energy is larger than twice the bandgap of semiconductors. A practical approach to demonstrate the CM involves the direct measurement of photocurrent in the device. Specifically, photocurrent measurement in quantum dots (QDs) is typically limited by high contact resistance and long carrier-transfer length, which yields a low CM conversion efficiency and high CM threshold energy. Here, the local photocurrent is measured to evaluate the CM quantum efficiency from a QD-attached Au tip of a conductive atomic force microscope (CAFM) system. The photocurrent is efficiently measured between the PbS QDs anchored on a Au tip and a graphene layer on a SiO2/Si substrate as a counter electrode, yielding an extremely short channel length that reduces the contact resistance. The quantum efficiency extracted from the local photocurrent data with an incident photon energy exhibits a step-like behavior. More importantly, the CM threshold energy is as low as twice the bandgap, which is the lowest threshold energy of optically observed QDs to date. This enables the CAFM-based photocurrent technique to directly evaluate the CM conversion efficiency in low-dimensional materials.
关键词： lead sulfide quantum dots,conductive atomic force microscopy,carrier multiplication,photocurrent measurement
更新于2025-09-16 10:30:52
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Fabrication and performance of AC-coupled LGADs
摘要： Detectors that can simultaneously provide ?ne time and spatial resolution have attracted wide-spread interest for applications in several ?elds such as high-energy and nuclear physics as well as in low-energy electron detection, photon science, photonics and imaging. Low-Gain Avalanche Diodes (LGADs), being fabricated on thin silicon substrates and featuring a charge gain of up to 100, exhibit excellent timing performance. Since pads much larger than the substrate thickness are necessary to achieve a spatially uniform multiplication, a ?ne pad pixelation is di?cult. To overcome this limitation, the AC-coupled LGAD approach was introduced. In this type of device, metal electrodes are placed over an insulator at a ?ne pitch, and signals are capacitively induced on these electrodes. At Brookhaven National Laboratory, we have designed and fabricated prototypes of AC-coupled LGAD sensors. The performance of small test structures with di?erent particle beams from radioactive sources are shown.
关键词： Charge transport and multiplication in solid media,Detector modelling and simulations II (electric ?elds, charge transport, multiplication and induction, pulse formation, electron emission, etc),Solid state detectors,Timing detectors
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Charge-coupled Device with Integrated Electron Multiplication for Low Light Level Imaging
摘要： Design of the charge-coupled device with the effect of electron multiplication is proposed. The increase of signal-to-noise ratio under low illumination as compared to the device without electron multiplication effect is demonstrated. The measurements at various temperature conditions and supply voltages have been carried out. The optimal operating mode of the proposed device is suggested.
关键词： temperature investigations,electron multiplication,electron-multiplying charge-coupled device,light level,electron-multiplying gain
更新于2025-09-12 10:27:22
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Photomultiplication Type Broad Response Organic Photodetectors with One Absorber Layer and One Multiplication Layer
摘要： Broad response organic photodetectors (OPDs) with photomultiplication (PM) effect are achieved with one absorber layer and one multiplication layer. The response range of the PM-OPDs is primarily determined by materials in the absorber layer, the external quantum efficiency (EQE) of the PM-OPDs is mainly controlled by the multiplication layer. Here, double-layered PM-OPDs were designed with the structure of ITO/ZnO/PM6:Y6/PC71BM:P3HT (100:5, wt/wt)/Au, where PM6:Y6 is employed as absorber layer and PC71BM:P3HT is used as multiplication layer. The optimal PM-OPDs exhibit broad response covering 350-950 nm. Meanwhile, the optimal PM-OPDs exhibit the largest EQE value of ~1200% and the maximum specific detectivity (D*) of ~6.8 × 10-12 cm Hz1/2 W-1 under 10 V bias. This double-layered approach may be a smart strategy to realize PM-OPDs with easily adjustable response range.
关键词： Organic photodetectors,Photomultiplication,Absorber layer,Multiplication layer,Broad response
更新于2025-09-12 10:27:22
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Materials for Nonlinear Optics in the GHz-THz Range
摘要： This talk starts with an outline of our hybrid approach combining Nonequilibrium Green's Functions with the Boltzmann equation for the nonlinear response of semiconductor superlattices. The nonlinearities are controllable and very good agreement has been found between theory and experiments. Next, we address the efficiency of the superlattices as frequency multipliers and their feasibility for room temperature THz radiation sources based on multiplication of GHz inputs.
关键词： semiconductor superlattices,THz,Boltzmann equations,GHz,nonequilibrium Green’s functions,frequency multiplication
更新于2025-09-11 14:15:04
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Noise characteristics improvement of submicron InP/InGaAs avalanche photodiode for laser detection system
摘要： InP/InGaAs avalanche photodiodes have attracted much attention in optoelectronics and long distance optical communication systems due to their high bit rate and gain-bandwidth. In this paper, to improve the noise characteristics in laser detection systems, separate absorption, grading, charge, and multiplication InP/InGaAs avalanche photodiode (SAGCM APD) with double guard rings and three thin layers of InGaAsP has been simulated. In addition, the multiplication width of SAGCM APD has been optimized which enhances the noise characteristics. The Photocurrent and dark current are acquired as and resulting in superior electrical properties among the other works. The excess noise factor in the constant mean gain of has been reduced 10.3% in comparison with recent SAGCM APDs. The calculated results show that the reduction of dark current and the excess noise factor increase the SNR for about orders of magnitude.
关键词： InP/InGaAs avalanche photodiode,SAGCM APD,Noise characteristics,Multiplication width,Laser detection system,Signal-to-noise ratio
更新于2025-09-11 14:15:04
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Fatigue crack branching in laser melting deposited Ti–55511 alloy
摘要： With the improvement of GPU’s general computing capacity, the use of parallel computing to solve some dif?cult problems with large amount of data and intensive computing tasks has become the trend of the times. In GPU general computing, CUDA and OpenCL have been widely used and studied. However, the two parallel programming models generally exist the weakness that whose API is too close to the underlying hardware, which makes programming inef?cient and is not suitable for the large-scale parallel tasks that require rapid implementation. OpenACC is a relatively advanced and simple programming language, which can achieve rapid parallelization, but the computing effect of the program is relatively low (generally lower than CUDA). Therefore, this paper tries to combine CUDA and OpenACC for mixed parallelization. This way not only greatly reduces the workload of code conversion, but also has a computing performance no less than a pure CUDA program.
关键词： matrix multiplication,OpenACC,CUDA
更新于2025-09-11 14:15:04
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Flexible photonic generation of frequency multiplication millimeter-wave vector signal based on dynamic pre-coding algorithm with dispersion compensation
摘要： The flexible photonic generation of millimeter-wave (mm-wave) vector signal adopting frequency multiplication enabled by two paralleled phase modulators and pre-coded radio frequency (RF) signals based on dynamic pre-coding algorithm is proposed and demonstrated. One driving signal has the original phase information and a phase deviation for dispersion compensation while the other signal has an opposite phase information and the same compensation phase. The amplitude depends on that of the regular vector symbol and the ratio of driving voltage to half-wave voltage of the phase modulator (PM). Two RF signals modulate the identical light waves from one laser via phase modulators respectively. The light waves are then transmitted over a fiber link after the selection of proper orders of harmonics by the wavelength selective switch (WSS). At the receiver, the optical signal is applied directly to a photodetector (PD) to generate the mm-wave vector signal at the desired frequency. The simulation of proposed scheme with radio over fiber (RoF) link transmission has been build. The result shows that the error vector magnitude (EVM) of generated 60GHz, 100GHz, and 140GHz 16 quadrature-amplitude-modulation (QAM) signals of 1Gb/s is no more than 20% after 80 km fiber transmission when the power into PD is no less than -10 dBm under ideal condition.
关键词： mm-wave generation,dispersion compensation,RoF,frequency multiplication,pre-coding
更新于2025-09-11 14:15:04