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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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Doping-induced giant rectification and negative differential conductance (NDC) behaviors in zigzag graphene nano-ribbon junction
摘要： By p-type and n-type doping on the electrode edges of V-notched zigzag graphene nano-ribbons (ZGNRs), four V-notched ZGNR-based PN-junctions are designed theoretically. The electronic transport properties of the doped and un-doped V-notched ZGNRs are studied applying non-equilibrium Green’s function method combined with the density functional theory. The numerical results show that, the doped systems are less conductive than the un-doped system, because after doping the transition states become localized. To our surprise, the ZGNR-based PN-junctions do not show obvious rectification by purely doping the boron atoms and nitrogen atoms on the edges of two ZGNR electrodes respectively. However, after hydrogenated the doped boron atoms and nitrogen atoms, the ZGNR systems present giant rectifications with the maximum rectification ratios up to 106 ～ 107, which attributed to the vanishing of overlap between left-electrode sub-band and right-electrode sub-band in the negative bias regime after the doped boron and nitrogen atoms being hydrogenated. Due to the same reason, the hydrogenated doping systems also show large negative differential conductance behaviors.
关键词： Giant rectification,Negative differential conductance,Graphene nano-ribbon junction,Boron and nitrogen doping
更新于2025-09-23 15:22:29
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Step-Double-Zone-JTE for SiC Devices with Increased Tolerance to JTE Dose and Surface Charges
摘要： In this paper, an edge termination structure, referred to as step-double-zone junction termination extension (Step-DZ-JTE), is proposed. Step-DZ-JTE further improves the distribution of the electric field (EF) by its own step shape. Step-DZ-JTE and other termination structures are investigated for comparison using numerical simulations. Step-DZ-JTE greatly reduces the sensitivity of breakdown voltage (BV) and surface charges (SC). For a 30-μm thick epi-layer, the optimized Step-DZ-JTE shows 90% of the theoretical BV with a wide tolerance of 12.2 × 10^12 cm^?2 to the JTE dose and 85% of the theoretical BV with an improved tolerance of 3.7 × 10^12 cm^?2 to the positive SC are obtained. Furthermore, when combined with the field plate technique, the performance of the Step-DZ-JTE is further improved.
关键词： breakdown voltage (BV),edge termination,junction termination extension (JTE),silicon carbide (SiC)
更新于2025-09-23 15:22:29
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Online Junction Temperature Extraction of SiC Power MOSFETs with Temperature Sensitive Optic Parameter (TSOP) Approach
摘要： Accurate information of the junction temperature of SiC power MOSFETs ensures safe operation and helps reliability assessment of the devices. In this paper, an online junction temperature extraction method is proposed based on the electroluminescence phenomenon of the body diode of SiC power MOSFETs. It is found that during the forward conduction interval of the body diode, visible blue light is emitted around the chip, which ascribes to the radiative recombination in the low doped region of SiC MOSFETs. Experimental results suggest the light intensity changes linearly with the variation of the temperature and behaves as a temperature sensitive optic parameter (TSOP). Further, an electro-thermal-optic model is proposed to reveal the relationship between electroluminescence intensity, forward current and junction temperature. Based on the TSOP, an online junction temperature extraction method is proposed for SiC MOSFETs and verified in a SiC MOSFET based inverter. Compared with state-of-the-art methods, the proposed junction temperature measurement method is contactless and immune from the aging of the package.
关键词： junction temperature extraction,Body diode,thermal management,electroluminescence,SiC MOSFETs
更新于2025-09-23 15:22:29
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Surface enhanced Raman scattering on molecule junction
摘要： Surface enhanced Raman scattering (SERS) is a powerful tool to study a small number of molecules adsorbed on metal surface. Recently, SERS is utilized to investigate the atomic structure of the molecule junction, which is a key component of molecular electronic devices. It is because the molecule is trapped between nano gap electrodes, and strong enhanced ?eld is formed in the gap. The Raman signal from the molecule in the molecular junction is selectively observed. The SERS was ?rst studied for the molecule junction, where small number of molecules bridge metal electrodes. Currently, the SERS of the single molecule junction is also reported. In this review, we discuss the history of the SERS of the molecule junction, and application of SERS to the molecule junction. Structural change induced by the application of the voltage across the junction and the chemical reaction on the single molecule junction have been reported with SERS.
关键词： Surface enhance Raman scattering,Molecular electronics,Single molecular junction
更新于2025-09-23 15:21:21
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Engineering hierarchical porous oxygen-deficient TiO2 fibers decorated with BiOCl nanosheets for efficient photocatalysis
摘要： The hierarchical porous oxygen-deficient TiO2 (TiO2-δ) fibers decorated with BiOCl nanosheets, for the first time, were synthesized through a sol-gel method combined with centrifugal spinning, and subsequent heat treatment under steam. Therein, the byproduct water-soluble NaCl crystal was recycled and used as the self-manufactured and self-sacrificial template. The dissolving out of NaCl for the in situ preparation of BiOCl on the surface of TiO2-δ generates rich mesoporous fiber structure. The flower-like BiOCl nanosheets provide large surface area for the adsorption of reactants, and more light scattering/reflection channels for enhancing light absorption. A series of characterizations confirmed that the introduction of oxygen vacancies in TiO2 broadens the light response to visible range, and the promotion of charge separation due to the formation of p-n junction between BiOCl and TiO2-δ. As a result, the BiOCl/TiO2-δ fiber exhibits enhanced broadband photocatalytic performance in the degradation of reactive brilliant red and colorless phenol. The apparent reaction rate constant achieved by the optimized BiOCl/TiO2-δ composite (0.0636 min-1) far surpasses that of TiO2-δ fibers (0.0026 min-1) by a factor of 24 under visible light irradiation. The reactive species involved in photocatalysis were detected by scavenger experiments and electron spin resonance spectra. The possible charge transfer processes and mechanism were explored and discussed in detail. This work provides novel insight into the design and synthesis of broadband and effective heterostructure photocatalysts for practical wastewater treatment.
关键词： BiOCl,oxygen-deficient TiO2,p-n junction,broadband photocatalysis
更新于2025-09-23 15:21:21
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Photoelectricity and thermoelectricity in organic chlorophyll phototransistors
摘要： As one kind of organic semiconductor materials, Chlorophyll has been attracted great attention with remarkable optical properties. Here, we demonstrate photoresponse and thermoelectric current in the biological Chlorophyll A field effect phototransistors (FEpTs). Meanwhile, it exhibits excellent performances including high responsivity (5×1013 A/W) and relatively fast response time (rise time ~ 20.3 s, fall time ~ 28.2 s) under illumination by 405 nm. Utilizing thermionic emission theory and typical Arrehenius plot, Schottky barrier B is found to be 76.6 meV. The biological phototransistor via low-cost, simple, and scalable fabrication processes opens up new opportunities to realize flexible, transparent organic electronic, and biologically optoelectronic devices.
关键词： Schottky junction,photoelectricity and thermoelectricity,Chlorophyll,Organic phototransistor
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Stability of carbon nanotube cold cathode electron beam (C-beam) with vacuum brazing process
摘要： A modularization of electronic parts in electrical devices is a key feature for system integration. Especially, x-ray tube fabrication process has been stayed in an obsolete manner due to the utilizing of classical thermionic x-ray sources. But cold cathode emitters such as carbon based materials with nanoscale dimension are expected to replace the conventional wired tungsten filaments due to their outstanding electrical and mechanical properties. To facilitate cold cathode emitter as an x-ray source, state of the arts bonding techniques are required. In this study, carbon nanotube grown Si wafers were successfully bonded to the metal carrier via vacuum brazing process and no electrical degradation of CNT (carbon nanotubes) emitters were observed after the process. Finally, we evaluated the stability of electron beam current density for device reliability. We expect that the cost-effective and facile technique could be applied for cold cathode based x-ray tube manufacturing process.
关键词： carbon nanotubes (CNTs),brazing,x-ray tube,junction,cold cathode
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Photosensitivity of single silicon high-aspect-ratio tips with different doping levels
摘要： Photosensitivity of single lightly p-doped, highly p-doped, with an integrated p/n junction and intrinsic high-aspect-ratio (HAR) silicon tips was investigated in an ultra-high vacuum environment. The current-voltage characteristics (I-V) of the lightly doped p-type HAR tips showed a characteristic current saturation at around 10-12 nA, whereas the HAR Si tips with p/n junction showed similar saturation phenomena, however, at much smaller current values starting at ~20- 30 pA. Optical switching under a halogen lamp illumination resulted in at least 2-4 times higher saturation currents and showed a linear dependence between the illumination power and the FE current, for both types of structures. In case of the highly p-doped HAR tips optical current switching effects, i. e. current saturation, were observed at rather low current levels 1-2 pA. Intrinsic HAR Si-tips showed relative unstable field emission behavior without a clear evidence of the photosensitivity.
关键词： photosensitivity,Si p/n junction,p-type Si,field emission
更新于2025-09-23 15:21:21
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CuO/ZnO Heterojunction Nanoarrays for Enhanced Photoelectrochemical Water Oxidation
摘要： Photoelectrochemical (PEC) water splitting offers a promising route for producing chemical energy from abundant solar energy, but a bottleneck remains for PEC practical applications because of the lack of efficient, stable and earth-abundant photoelectrodes. Here, we report simultaneous improvements in carrier separation and light harvesting by constructing p-n heterojunctions in CuO/ZnO nanorod arrays. The novelty of this work is developing a new strategy for preparing a CuO/ZnO p-n heterojunction photoanode for PEC water splitting, in which Cu(OH)2/ZnO is first prepared by a chemical solution strategy and then transformed into CuO/ZnO by annealing. The CuO/ZnO heterojunction photoanode exhibited a significant negative shift of 150 mV for the onset potential and an approximately 4-fold enhancement in the photocurrent at 1.23 V vs reversible hydrogen electrode (RHE) compared with those of pristine ZnO NRs. This work offers a facile strategy for preparing oxide-based p-n heterojunction photoanodes for enhanced PEC water splitting.
关键词： Water Splitting,Light Absorption,Photoelectrochemical (PEC),Heterojunction,Photoanode,P-N Junction
更新于2025-09-23 15:21:21