- 标题
- 摘要
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- 实验方案
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AlGaN/GaN MIS-HEMT with PECVD SiNx, SiON, SiO2 as Gate Dielectric and Passivation Layer
摘要： Three different insulator layers SiNx, SiON, and SiO2 were used as a gate dielectric and passivation layer in AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMT). The SiNx, SiON, and SiO2 were deposited by a plasma-enhanced chemical vapor deposition (PECVD) system. Great differences in the gate leakage current, breakdown voltage, interface traps, and current collapse were observed. The SiON MIS-HEMT exhibited the highest breakdown voltage and Ion/Ioff ratio. The SiNx MIS-HEMT performed well in current collapse but exhibited the highest gate leakage current density. The SiO2 MIS-HEMT possessed the lowest gate leakage current density but suffered from the early breakdown of the metal–insulator–semiconductor (MIS) diode. As for interface traps, the SiNx MIS-HEMT has the largest shallow trap density and the lowest deep trap density. The SiO2 MIS-HEMT has the largest deep trap density. The factors causing current collapse were confirmed by Photoluminescence (PL) spectra. Based on the direct current (DC) characteristics, SiNx and SiON both have advantages and disadvantages.
关键词： interface traps,MISHEMT,gallium nitride,PECVD,current collapse,dielectric layer
更新于2025-09-23 15:22:29
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Tunable Spin Seebeck Diode with Magnonic Spin Tunneling Junction
摘要： We theoretically investigate the spin–wave spin current induced by the spin Seebeck effect in magnonic spin tunneling junctions (MSTJs) for arbitrary magnetization directions. We show that the MSTJ functions as a tunable spin Seebeck diode in which the tunneling spin current can be turned on and off with high efficiency by controlling the magnetization direction.
关键词： spin current,spin Seebeck effect,diode,magnetization direction,magnonic spin tunneling junction
更新于2025-09-23 15:22:29
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Electron transfer during binding processes between thiolate molecules and Au nano-islands
摘要： We investigated electron transfer during the time-dependent binding processes between thiolate molecules and Au nano-islands by observing tunneling current with an interdigitated microelectrode supporting the sputtered Au nano-islands (IME@AuNI). The time-dependent optical and electrical signal variation during the binding process was examined for five kinds of thiolates. As the immersion time was prolonged, the optical absorbance increased, whereas the current passing through the IME@AuNI decreased. Importantly, the spectral and current characteristics depended on the thiolate structure, because of the formation of capping layer in accordance with thiolate structure. These results are mainly attributed to synergistic effects of electron transfer from Au nano-islands to thiolate molecules and bridging effects of thiolate molecules among Au nano-islands.
关键词： Au nano-islands,Thiolate molecules,Electron transfer,Localized surface plasmon resonance,Tunneling current
更新于2025-09-23 15:22:29
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A unified figure of merit for interband and intersubband cascade devices
摘要： By exploring a semi-empirical model, the saturation current density J0 is identified to manifest the significant difference in carrier lifetime between interband cascade devices (ICDs) and intersubband quantum cascade devices (QCDs). Based on this model, the values of J0 have been extracted for a large number of ICDs and QCDs from their current-voltage characteristics at room temperature. By analyzing and comparing available ICD and QCD data, we demonstrate how J0 can be used as a unified figure of merit to evaluate both interband and intersubband cascade configurations for their device functionality. The significance of J0 on the performances of mid-infrared detectors and photovoltaic cells is illustrated by comparing the measured detectivity (D*) and the estimated open-circuit voltage (Voc), respectively. From extracted values of J0, which are more than one order of magnitude lower in ICDs than that in QCDs with similar transition energies in active regions, and discussion of the consequences on device performance, the advantages of interband cascade configurations over intersubband quantum cascade configurations have been clearly revealed based on the same framework. The overall picture for both QCDs and ICDs sheds light from the perspective of a united figure of merit, which will provide useful guidance and stimulation to the future development of both ICDs and QCDs.
关键词： Saturation current density,Interband cascade,Quantum cascade,Open-circuit voltage
更新于2025-09-23 15:22:29
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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) - Comparison Study of Surge Current Capability of Body Diode of SiC MOSFET and SiC Schottky Diode
摘要： The superior performance of the SiC MOSFETs operating in synchronous mode converter without external antiparallel SiC Schottky diodes have been demonstrated recently. However, there are few studies of the surge current capability of the SiC MOSFET's body diode, leading severe concern for its ruggedness in practical power converter applications. The purpose of this paper is to experimentally compare the non-repetitive surge current capability of the SiC MOSFET's intrinsic body diode and SiC Schottky diode, and analyze the physical mechanisms of their degradation after surge current stress. Their surge current capability and electrical characteristics before and after surge current stress are measured and analyzed. Experimental study shows that the non-repetitive peak surge current of the SiC MOSFET’s body diode is slightly larger than that of the SiC Schottky diodes. The degradation of the SiC Schottky diode after surge current stress is accompanied with the increase of drain leakage current, while the degradation of the SiC MOSFET after the body diode’s surge current stress is accompanied with the variation of the threshold voltage and input capacitance of the SiC MOSFET. The analysis shows that the degradation of the SiC MOSFET after the surge current stress may be correlated with the interface traps of SiC/SiO2 interface.
关键词： Body diode,SiC Schottky Diode,SiC MOSFET,Surge current
更新于2025-09-23 15:22:29
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Different Isolation Processes for Free-Standing GaN p-n Power Diode with Ultra-High Current Injection
摘要： In this article, we report on the fabrication and high performance of power p-n diodes grown on free-standing (FS) GaN substrate. The key technique to enhance the high breakdown voltage and suppress the surface leakage current is the isolation process. The mesa-structure diode is generally formed by utilizing the inductively coupled plasma reactive ion etching (ICP-RIE); however, it always induces high surface damages and thus causes a high leakage current. In this study, we propose a planar structure by employing the oxygen ion implantation to frame the isolation region. By following the crucial process, the fabricated mesa- and planar-type diodes exhibit the turn-on voltages of 3.5 and 3.7 V, specific on-resistance (RONA) of 0.42 and 0.46 mΩ-cm2, and breakdown voltage (VB) of 2640 and 2880 V, respectively. The corresponding Baliga’s figures of merit (BFOM, i.e., VB2/RONA) are 16.6 and 18 GW/cm2, respectively. The BFOM of 18 GW/cm2 is the highest reported value for FS-GaN diode. From the temperature dependent measurements, the planar-type diode also shows the better leakage current and thermal stability than the mesa-type diode.
关键词： leakage current,Baliga’s figure of merit,breakdown voltage,planar diode,implantation,GaN substrate
更新于2025-09-23 15:22:29
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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) - Power Factor Operation of a Boost Integrated Three-Phase Solar Inverter using Current Unfolding and Active Damping Methods
摘要： This paper proposes a three-phase solar inverter with integrated boost function. The circuit operating principle is based on current unfolding and injection method. This approach requires only two high frequency switches for the boost function as well as shaping its output currents, thus leading to a significant reduction in switching losses. Other switches only operate at line frequency to unfold the output currents to sinusoidal three-phase currents, and thus can be optimized to reduce conduction losses. The proposed inverter therefore could deliver high efficiency. This paper discusses the basic operating principle and control method for the inverter. The paper proposes an active damping method to overcome intrinsic oscillation due to overlapping time in switching operation. It also shows that the inverter is capable of supplying reactive power up to a limit of 0.866 power factor. Stable operation of the proposed inverter is confirmed by both simulation and experiment.
关键词： current unfolding,active damping,three-phase inverter,oscillation
更新于2025-09-23 15:22:29
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A Hybrid MMC-Based Photovoltaic and Battery Energy Storage System
摘要： This paper proposes a new configuration and its control strategy for a modular multilevel converter (MMC)-based photovoltaic (PV)-battery energy storage (BES) system. In the MMC-based PV-BES system, each PV submodule is interfaced from its dc side with multiple PV generators using isolated dual active bridge (DAB) dc-dc converters. One BES system is embedded into each arm of the converter and is connected to the dc port of the associated BES submodule using multiple isolated DAB converters. The embedded BES systems are used to smooth the output power of the PV generators and limit the rate of change of the power delivered to the host grid. Moreover, they enable compensation of power mismatches between the arms and legs of the system by exchanging power with the arms of the converter. The paper then proposes a hybrid power mismatch elimination strategy using a combination of power exchange with the arms of the converter and internal power flow control of the MMC. The proposed hybrid power mismatch elimination strategy employs BES systems and differential currents to compensate power mismatches and transfer power between the arms and legs of the converter, respectively. The effectiveness of the proposed power smoothing technique using the embedded BES systems and hybrid power mismatch elimination strategy is demonstrated using time-domain simulations conducted on a switched model of the PV-BES system in PSCAD/EMTDC software environment.
关键词： control,modular multilevel converter,power electronics,battery energy storage,photovoltaic,power mismatch,Differential current,energy conversion,integration
更新于2025-09-23 15:22:29
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Determining Series Resistance for Equivalent Circuit Models of a PV Module
摘要： Literature describes various methods for determining a series resistance for a photovoltaic device from measured IV curves. We investigate use of these techniques to estimate the series resistance parameter for a single diode equivalent circuit model. With simulated IV curves we demonstrate that the series resistance values obtained by these techniques differ systematically from the known series resistance parameter values used to generate the curves, indicating that these methods are not suitable for determining the series resistance parameter for the single diode model equation. We present an alternative method to determine the series resistance parameter jointly with the other parameters for the single diode model equation, and demonstrate the accuracy and reliability of this technique in the presence of measurement errors.
关键词： Current-voltage characteristics,parameter extraction,electric resistance,solar panels
更新于2025-09-23 15:22:29
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Application of Airborne Infrared Remote Sensing to the Study of Ocean Submesoscale Eddies
摘要： This paper explores the use of infrared remote sensing methods to examine submesoscale eddies that recur downstream of a deep-water island (Santa Catalina, CA). Data were collected using a mid-wave infrared camera deployed on an aircraft flown at an altitude of 3.7 km, and research boats made nearly simultaneous measurements of temperature and current profiles. Structure within the thermal field is generally adequate as a tracer of surface fluid motions, though the imagery needs to be processed in a novel way to preserve the smallest-scale tracer patterns. In the case we focus on, the eddy is found to have a thermal signature of about 1 km in diameter and a cyclonic swirling flow. Vorticity is concentrated over a smaller area of about 0.5 km in diameter. The Rossby number is 27, indicating the importance of the centrifugal force in the dynamical balance of the eddy. By approximating the eddy as a Rankine vortex, an estimate of upward doming of the thermocline (about 14 m at the center) is obtained that agrees qualitatively with the in-water measurements. Analysis also shows an outward radial flow that creates areas of convergence (sinking flow) along the perimeter of the eddy. The imagery also reveals areas of localized vertical mixing within the eddy thermal perimeter, and an area of external azimuthal banding that likely arises from flow instability.
关键词： infrared imagery,surface current,remote sensing of environment,submesoscale eddies,kinematics and dynamics
更新于2025-09-23 15:22:29