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- 摘要
- 关键词
- 实验方案
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Terahertz 1-bit digital dynamic phase programmable metasurface based on AlGaN/GaN heterostructure
摘要： We consider diffusion fields induced by a finite number of spatially localized sources and address the problem of estimating these sources using spatiotemporal samples of the field obtained with a sensor network. Within this framework, we consider two different time evolutions: the case where the sources are instantaneous, as well as, the case where the sources decay exponentially in time after activation. We first derive novel exact inversion formulas, for both source distributions, through the use of Green's second theorem and a family of sensing functions to compute generalized field samples. These generalized samples can then be inverted using variations of existing algebraic methods such as Prony's method. Next, we develop a novel and robust reconstruction method for diffusion fields by properly extending these formulas to operate on the spatiotemporal samples of the field. Finally, we present numerical results using both synthetic and real data to verify the algorithms proposed herein.
关键词： Prony's method,Spatiotemporal sampling,sensor networks,finite rate of innovation (FRI),diffusion fields
更新于2025-09-19 17:13:59
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Epitaxial n++-InGaAs ultra-shallow junctions for highly scaled n-MOS devices
摘要： High electron mobility III-V semiconductors like InGaAs are excellent candidates for sub-10 nm n-metal-oxide-semiconductor (nMOS) devices. One of the critical challenges in downscaling III-V devices is achieving low-resistance contacts by forming low-defect, ultra-shallow junctions < 9 nm in depth, with n-type dopant concentrations above 1019 cm?3. In the current study, we combine time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profile analysis, atomic force microscopy (AFM) imaging, and high-resolution transmission electron microscopy (HR-TEM) to determine the optimal doping strategy for growing Si-doped n++-In0.25Ga0.75As ultra-shallow junctions by molecular beam epitaxy. We test three different approaches to doping: homogeneous co-deposition, single δ-layer (continuous) doping, and triple δ-layer (pulsed) doping. We demonstrate the formation of technologically suitable n++-In0.25Ga0.75As junctions 5–7 nm deep, grown under As-rich conditions with a single δ-layer at temperatures as low as 400 °C. These junctions have peak Si concentrations between 6 × 1019 and 1 × 1020 cm?3 and high crystal quality. The surface self-organizes into smooth ripples or mounds, up to a peak dopant concentration of ~2 × 1020 cm-3. Above this value, enhanced diffusion of Si and In due to a large population of Ga vacancies increases lattice strain in the semiconductor epilayer, triggering a transition from 2D growth to 3D growth and the formation of In0.85Ga0.15As clusters on the surface.
关键词： Time-of-flight secondary ion mass spectrometry,Indium gallium arsenide,Semiconductor growth,Ultra-shallow junctions,Self-organization,Solid-state diffusion
更新于2025-09-19 17:13:59
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Enhanced efficiency and stability of perovskite solar cells by 2D perovskite vapor-assisted interface optimization
摘要： Organic-inorganic perovskites solar cells (PSCs) have attracted great attention due to their rapid progress in power conversion efficiency (PCE). However, there is still an enormous challenge to achieve both high efficiency and stability devices as the decomposition of perovskite materials under humid and light conditions. Herein, we demonstrate that high efficiency and stability of PSCs can be obtained by the reaction of three-dimensional (3D) perovskite with 1, 4-butanediamine iodide (BEAI2) vapor. The incorporation of BEAI2 intensively promotes the crystallization of perovskite film with large grain size (~500 nm). Further characterization reveals that the post-treatment perovskite film delivered low interface trap density with long carrier lifetime (> 200 ns), long carrier diffusion length (> 600 nm) and large carrier mobility (> 1.5 cm2 V-1 S-1). Solar cells employing such post-treatment films demonstrated 19.58% PCE without hysteresis. Moreover, the post-treatment devices can retain over 90% original efficiencies stored under ambient atmospheric conditions and exhibit better stability under 85 °C and continuous illumination as a two-dimensional (2D) perovskite thin layer is formed on the surface/or at the grain boundaries of 3D perovskite. This study offers an effective way to obtain PSCs with high efficiency and stability.
关键词： Mobility,Post-treatment,Perovskite solar cells,2D/3D perovskite,Carrier diffusion length
更新于2025-09-19 17:13:59
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Extraordinarily long diffusion length in PM6:Y6 organic solar cells
摘要： The PM6:Y6 bulk-heterojunction (BHJ) blend system achieves high short-circuit current (JSC) values in thick photovoltaic junctions. Here we analyse these solar cells to understand the observed independence of the short-circuit current upon photoactive layer thickness. We employ a range of optoelectronic measurements and analyses, including Mott-Schottky analysis, CELIV, photoinduced absorption spectroscopy, Kelvin-probe potential measurements and simulations, to conclude that, for the device series studied, the invariant photocurrent for devices with different active layer thicknesses is associated with the Y6 diffusion length exceeding 300 nm. This is despite an unintentional doping that occurs in PM6 and the associated space-charge effect, which is expected to be even more profound upon photogeneration. This extraordinarily long diffusion length - which is an order of magnitude larger than typical values for organics - dominates transport in the flat-band region of thick junctions. Our work suggests that the performance of the doped PM6:Y6 organic solar cells resembles that of inorganic devices with diffusion transport playing a pivotal role. Ultimately, this is expected to be a key requirement for the fabrication of efficient, high-photocurrent, thick organic solar cells.
关键词： bulk-heterojunction,photovoltaic junctions,organic solar cells,diffusion length,PM6:Y6
更新于2025-09-19 17:13:59
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Non-Markovian entanglement transfer to distant atoms in a coupled superconducting resonator
摘要： In this paper, we investigate the non-Markovian effects on the entanglement transfer to the distant non-interacting atom qubits, which are embedded in a coupled superconducting resonator. The master equation governing the dynamics of the system is derived by the non-Markovian quantum state diffusion (NMQSD) method. Based on the solution, we show that the memory effect of the environment can lead to higher entanglement revival and make the entanglement last for a longer time. That is to say, the non-Markovian environment can enhance the entanglement transfer. It is also found that the maximum entanglement transferred to distant atoms can be modified by appropriately selecting the frequency of the modulated inter-cavity coupling. Moreover, with the initially anti-correlated state, the entanglement between the cavity fields can be almost completely transferred to the separated atoms. At last, we also show that the memory effect have a significant impact on the generation of entanglement from the initially non-entangled states.
关键词： quantum state diffusion,Non-Markovian,Entanglement transfer
更新于2025-09-19 17:13:59
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Self‐Assembly of Nanoparticle‐Spiked Pillar Arrays for Plasmonic Biosensing
摘要： Plasmonic biosensors have demonstrated superior performance in detecting various biomolecules with high sensitivity through simple assays. Scaled-up, reproducible chip production with a high density of hotspots in a large area has been technically challenging, limiting the commercialization and clinical translation of these biosensors. A new fabrication method for 3D plasmonic nanostructures with a high density, large volume of hotspots and therefore inherently improved detection capabilities is developed. Specifically, Au nanoparticle-spiked Au nanopillar arrays are prepared by utilizing enhanced surface diffusion of adsorbed Au atoms on a slippery Au nanopillar arrays through a simple vacuum process. This process enables the direct formation of a high density of spherical Au nanoparticles on the 1 nm-thick dielectric coated Au nanopillar arrays without high-temperature annealing, which results in multiple plasmonic coupling, and thereby large effective volume of hotspots in 3D spaces. The plasmonic nanostructures show signal enhancements over 8.3 × 108-fold for surface-enhanced Raman spectroscopy and over 2.7 × 102-fold for plasmon-enhanced fluorescence. The 3D plasmonic chip is used to detect avian influenza-associated antibodies at 100 times higher sensitivity compared with unstructured Au substrates for plasmon-enhanced fluorescence detection. Such a simple and scalable fabrication of highly sensitive 3D plasmonic nanostructures provides new opportunities to broaden plasmon-enhanced sensing applications.
关键词： surface diffusion,plasmonic biosensors,spherical metal nanoparticles,3D nanostructures,surface energy
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Timisoara, Romania (2019.10.17-2019.10.18)] 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Interharmonic and Harmonic Steady-State Computation of a Grid-Tied Photovoltaic System
摘要： We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool widely used in array signal processing and finite-rate-of-innovation (FRI) sampling. The proposed algorithm can reconstruct spatial samples. For large, this sampling requirement improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,finite rate of innovation,sphere,Annihilation filter,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-19 17:13:59
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CMOS 256-Pixel/480-Pixel Photovoltaic-Powered Subretinal Prosthetic Chips With Wide Image Dynamic Range and Bi/Four-Directional Sharing Electrodes and Their Ex Vivo Experimental Validations With Mice
摘要： After nearly half a century of research into the bias temperature instability, two classes of models have emerged as the strongest contenders. One class of models, the reaction-diffusion models, is built around the idea that hydrogen is released from the interface and that it is the diffusion of some form of hydrogen that controls both degradation and recovery. Although various variants of the reaction-diffusion idea have been published over the years, the most commonly used recent models are based on nondispersive reaction rates and nondispersive diffusion. The other class of models is based on the idea that degradation is controlled by first-order reactions with widely distributed (dispersive) reaction rates. We demonstrate that these two classes give fundamentally different predictions for the stochastic degradation and recovery of nanoscale devices, therefore providing the ultimate modeling benchmark. Using detailed experimental time-dependent defect spectroscopy data obtained on such nanoscale devices, we investigate the compatibility of these models with experiment. Our results show that the diffusion of hydrogen (or any other species) is unlikely to be the limiting aspect that determines degradation. On the other hand, the data are fully consistent with reaction-limited models. We finally argue that only the correct understanding of the physical mechanisms leading to the significant device-to-device variation observed in the degradation in nanoscale devices will enable accurate reliability projections and device optimization.
关键词： NBTI,dispersive reaction rates,first-order processes,PBTI,Bias temperature instability,reaction-diffusion,oxide defects,charge trapping
更新于2025-09-19 17:13:59
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Cations Functionalized Carbon Nano‐Dots Enabling Interfacial Passivation and Crystallization Control for Inverted Perovskite Solar Cells
摘要： Realizing the full potential of perovskite photovoltaic requires stringent control over nonradiative losses in the devices. Herein, the interfacial carrier recombination of inverted planar perovskite solar cells (PSCs) is suppressed using rationally designed natriumion-functionalized carbon nano-dots (CNDs@Na). The binding effect of carbon dots on Na+ inhibits the interstitial occupancy of alkali cations and reduces the microstrain of the polycrystalline film. Furthermore, modified surface wettability improves the ordering and crystal size of perovskite, which restrains ion diffusion and improves interfacial contact, leading to reduced interfacial charge recombination. Consequently, the effective interfacial passivation and crystallization control enhance the photovoltaic performance and long-term stability of PSCs, resulting in an efficiency of over 20% with negligible hysteresis.
关键词： natriumion-functionalized carbon nano-dots,perovskite solar cells,ion diffusion,trap densities,interface modifications
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Encapsulation Techniques Using Electrically Conductive Adhesives for Building-Integrated Photovoltaics
摘要： Gas leakage source detection and boundary tracking of continuous objects have received a significant research attention in the academic as well as the industries due to the loss and damage caused by toxic gas leakage in large-scale petrochemical plants. With the advance and rapid adoption of wireless sensor networks (WSNs) in the last decades, source localization and boundary estimation have became the priority of research works. In addition, an accurate boundary estimation is a critical issue due to the fast movement, changing shape, and invisibility of the gas leakage compared with the other single object detections. We present various gas diffusion models used in the literature that offer the effective computational approaches to measure the gas concentrations in the large area. In this paper, we compare the continuous object localization and boundary detection schemes with respect to complexity, energy consumption, and estimation accuracy. Moreover, this paper presents the research directions for existing and future gas leakage source localization and boundary estimation schemes with WSNs.
关键词： boundary detection and tracking,diffusion model,Wireless sensor networks (WSNs),source localization
更新于2025-09-19 17:13:59