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Reversible/Irreversible Photobleaching of Fluorescent Surface Defects of SiC Quantum Dots: Mechanism and Sensing of Solar UV Irradiation
摘要： Knowledge about photobleaching properties of the fluorescent surface defects of the semiconductor quantum dots (QDs) is crucial for their applications. Here, the photobleaching properties of the fluorescent surface defects of the colloidal 3C-SiC QDs are reported. The combined experimental and theoretical study reveals that the observed violet fluorescence at around 392 nm stems from the carboxylic acid group-related surface defects. When the SiC QDs are exposed to the UV irradiation, the 392 nm fluorescent surface defects show both reversible and irreversible photobleaching, whereas the 438 nm fluorescent surface defects show only irreversible photobleaching. The photochemical mechanisms dominating these phenomena are explored. The photobleaching property of the SiC QDs is utilized to detect the solar UV irradiation with high accuracy. The photobleaching of the SiC QDs is highly sensitive to the hydrogen or metal ion concentration in the colloid solution. These findings deepen the understanding of the properties of the fluorescent surface defects of the SiC QDs and pave the way for their applications in sensing.
关键词： photobleaching,silicon carbide quantum dots,surface defects,fluorescence mechanism
更新于2025-11-19 16:46:39
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Growth and Self-Assembly of Silicon–Silicon Carbide Nanoparticles into Hybrid Worm-Like Nanostructures at the Silicon Wafer Surface
摘要： This work describes the growth of silicon–silicon carbide nanoparticles (Si–SiC) and their self-assembly into worm-like 1D hybrid nanostructures at the interface of graphene oxide/silicon wafer (GO/Si) under Ar atmosphere at 1000 °C. Depending on GO film thickness, spread silicon nanoparticles apparently develop on GO layers, or GO-embedded Si–SiC nanoparticles self-assembled into some-micrometers-long worm-like nanowires. It was found that the nanoarrays show that carbon–silicon-based nanowires (CSNW) are standing on the Si wafer. It was assumed that Si nanoparticles originated from melted Si at the Si wafer surface and GO-induced nucleation. Additionally, a mechanism for the formation of CSNW is proposed.
关键词： nanoparticles,thermal reduction,silicon carbide,graphene oxide,self-assembly,silicon,nanowires
更新于2025-09-23 15:23:52
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An Improved Proposed Single Phase Transformerless Inverter with Leakage Current Elimination and Reactive Power Capability for PV Systems Application
摘要： Single-phase transformerless inverters are broadly studied in literature for residential-scale PV applications due to their great advantages in reducing system weight, cost and elevating system efficiency. The design of transformerless inverters is based on the galvanic isolation method to eliminate the generation of leakage current. Unfortunately, the use of the galvanic isolation method alone cannot achieve constant common mode voltage (CMV). Therefore, a complete elimination of leakage current cannot be achieved. In addition, modulation techniques of single-phase transformerless inverters are designed for the application of the unity power factor. Indeed, next-generation PV systems are required to support reactive power to enable connectivity to the utility grid. In this paper, a proposed single-phase transformerless inverter is modified with the clamping method to achieve constant CMV during all inverter operating modes. Furthermore, the modulation technique is modified by creating a new current path in the negative power region. As a result, a bidirectional current path is created in the negative power region to achieve reactive power generation. The simulation results show that the CMV is completely clamped at half the DC link voltage and the leakage current is almost completely eliminated. Furthermore, a reactive power generation is achieved with the modified modulation techniques. Additionally, the total harmonic distortion (THD) of the grid current with the conventional and a modified modulation technique is analyzed. The efficiency of the system is enhanced by using wide-bandgap (WBG) switching devices such as SiC MOSFET. It is observed that the efficiency of the system decreased with reactive power generation due to the bidirectional current path, which leads to increasing conduction losses.
关键词： leakage current,transformerless inverter,reactive power,wide-bandgap (WBG),silicon carbide (SiC),photovoltaic (PV) power system
更新于2025-09-23 15:23:52
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Depth Profiling of Carrier Lifetime in Thick 4H-SiC Epilayers Using Two-Photon Absorption
摘要： Depth profiling of the ambipolar carrier lifetime was performed in n-type, 140μm thick silicon carbide (SiC) epilayer using excitation by two-photon absorption (TPA) with a pulsed 586nm laser, and confocal measurement of time resolved photoluminescence (TRPL) decay from the excited region. A depth resolution of ≈10μm was obtained. The PL decay curves were analyzed using a recently developed formalism that takes into account the TPA excitation, carrier diffusion and surface/interface recombination. The carrier lifetime decreases near the top surface of the epitaxial layer as well as near its interface with the substrate.
关键词： Carrier lifetime profiling,Silicon Carbide
更新于2025-09-23 15:23:52
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Millimeter-Scale Growth of Single-Oriented Graphene on a Palladium Silicide Amorphous Film
摘要： It is widely accepted in condensed matter physics and material science communities that a single-oriented overlayer cannot be grown on an amorphous substrate because the disordered substrate randomizes the orientation of the seeds, leading to polycrystalline grains. In the case of two-dimensional materials such as graphene, the large-scale growth of single-oriented materials on an amorphous substrate has remained unsolved. Here, we demonstrate experimentally that the presence of uniformly oriented graphene seeds facilitates the growth of millimeter-scale single-oriented graphene with 3×4 mm2 on palladium silicide, which is an amorphous thin film, where the uniformly oriented graphene seeds were epitaxially grown. The amorphous palladium silicide film promotes the growth of the single-oriented growth of graphene by causing carbon atoms to be diffusive and mobile within and on the substrate. In contrast to these results, without the uniformly oriented seeds, the amorphous substrate leads to the growth of polycrystalline graphene grains. This millimeter-scale single-oriented growth from uniformly oriented seeds can be applied to other amorphous substrates.
关键词： silicon carbide,amorphous substrate,single orientation,graphene,palladium silicide
更新于2025-09-23 15:23:52
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The 1.2 kV 4H-SiC OCTFET: A New Cell Topology with Improved High Frequency Figures-of-Merit
摘要： A 1.2 kV rated 4H-SiC OCTFET device with octagonal-cell topology is proposed and experimentally demonstrated for the first time. The device was first optimized using TCAD numerical simulations. Devices were then successfully fabricated in a 6 inch foundry. From the measured electrical characteristics, the OCTFET is demonstrated to have 1.4× superior HF-FOM [Ron×Qgd], and 2.1× superior HF-FOM [Ron×Cgd] compared with the conventional linear-cell MOSFET.
关键词： Silicon carbide,ALL,Octagonal,Qgd,HF-FOMs,Cell,Cgd,MOSFET,4H-SiC
更新于2025-09-23 15:23:52
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An adapted method for analyzing 4H silicon carbide metal-oxide-semiconductor field-effect transistors
摘要： Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) are key devices for next-generation power electronics. However, accurate determination of device parameters from 3-terminal characteristics is hampered by the presence of interface traps. Here we present a method that, in contrast to previous evaluation schemes, explicitly considers those defects. A well-tractable parametrization of the SiC/SiO2-specific interface trap spectrum is introduced that reflects the body of known data. With this ingredient, we develop an analysis that targets for an accurate determination of device parameters from simple 3-terminal characteristics. For its validation, we investigate MOSFETs with significantly different defect densities. The resulting parameters – charge carrier density, mobility and threshold voltage – are in excellent agreement with Hall effect investigations on the very same devices, avoiding systematic errors inherent to conventional evaluation techniques. With this adapted scheme, 4H-SiC power MOSFETs, even packaged, can be meaningfully characterized, speeding up innovation cycles in energy-saving power electronics.
关键词： mobility,Silicon carbide,Hall effect,interface traps,threshold voltage,MOSFET
更新于2025-09-23 15:23:52
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Synthesis and photocatalytic properties of biomimetic morphology silicon carbide
摘要： Silicon carbide materials with bionic morphology are prepared by impregnation-calcination method using the template of leaf vein. The microstructure, element composition, and band gap of biomimetic morphology silicon carbide are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS). Photocatalytic property of biomimetic morphology silicon carbide has been measured by the dye decolorization reaction. The results demonstrate that calcination temperature has the important effect on the formation of silicon carbide. The morphology of silicon carbide can keep the original biomimetic shape of leaf vein template, and there is meosporous structure with a diameter of 2-4 nm on the interior of material. The average gain size of materials is about 16.9 nm and the specific surface area of materials is about 84.7 m2/g. After calculation, the band gap of material is 3.02 eV. For performance testing, the degradation rate of silicon carbide is 92.86% for the first time, and after the fourth repetition, the degradation rate decreased to 86.74%.
关键词： Biological Template,Silicon Carbide,Biomimetic Morphology,Photocatalytic Property
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - EMI Analysis of a High Power Silicon Carbide Two-level Inverter
摘要： Successive generations of aircraft demand more electrical energy as pneumatic and hydraulic systems are replaced with electrical components. The more electric aircraft (MEA) transformation aims to improve fuel economy, increase reliability, and lower operating costs. To fully enjoy the benefits of an additional improvements in the power density of the electrical distribution system are required. Silicon carbide (SiC) devices have many advantages over their silicon (Si) counterparts that can lead to improvements in the power density. However, their characteristically switching speeds can result in higher levels of electromagnetic interference (EMI). This research compares the performance of two high power three phase inverters; one is built from SiC MOSFETs and the other from Si IGBTs. The efficiency and conducted EMI are measured at a DC bus of 540 V and an output power exceeding 25 kW.
关键词： Silicon Carbide,Electromagnetic Interference (EMI),More Electric Aircraft
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Evaluation of 2.5 kV Silicon Carbide MOSFET for 1.5 kV Solar Inverter Application
摘要： 1.5 kV DC link voltage has been a trend for the solar industry. Moving from 1 kV to 1.5 kV DC voltage can increase string length, enhance inverter conversion ability, increase array block sizes, and improve performance. Multilevel converters are the natural choices while the control becomes more complicated. If a simple two-level converter is adopted, the 1.7 kV device may not be applicable considering the voltage derating for certain failure rate. Therefore, devices with higher blocking voltage should be considered. This paper reports for the first time the performance characterization of 2.5 kV Silicon Carbide (SiC) MOSFET. The potential application of this device for 1.5 kV solar inverter is also evaluated.
关键词： Solar Inverter,Silicon Carbide MOSFET,Silicon Carbide converter
更新于2025-09-23 15:22:29