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Topological interface modes in photonic superlattices containing negative-index materials
摘要： We study the topological properties of one-dimensional photonic superlattices consisting of alternating layers of positive- and negative-index materials. We find that Zak phases of photonic bands of such superlattices are related to the signs of the spatial average of their permittivity and permeability, and the polarization of incident light. Specifically, the Zak phases for transverse electric (TE) waves (transverse magnetic (TM) waves) are determined by only the sign of the spatially averaged permittivity (permeability) of the lattices. Only a single-polarized (TM or TE) topological interface mode occurs at the interface between air and the superlattice with single-negative average permittivity or permeability. The crucial dependence of the topological property of the superlattice on the light polarization suggests a polarization filter application. The topologically protected interface modes for both TM and TE polarizations can coexist at the interface separating air and the superlattices with simultaneously negative signs of averaged permittivity and permeability. The robustness of such topological interface modes for both TM and TE polarizations is also demonstrated.
关键词： polarization filter,negative-index materials,photonic superlattices,Zak phase,topological interface modes
更新于2025-09-23 15:22:29
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Effects of nitrogen-dopant bonding states on liquid-flow-induced electricity generation of graphene: A comparative study
摘要： We fabricate, measure and compare the effects of the bonding states of dopant nitrogen atoms in graphene devices, specifically on the liquid-flow-induced electricity by these devices. We find that nitrogen doping enhances the voltage induced by liquid flow regardless of the nitrogen bonding state. However, different nitrogen bonding states affect graphene’s conductivity differently: while graphitic nitrogen is suitable for electricity-generation applications, pyridinic nitrogen is hopeless for this purpose, due to the formation of symmetry-breaking defects of the latter.
关键词： Water-graphene interface,Nitrogen doped graphene,Flow-induced electricity generation
更新于2025-09-23 15:22:29
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<i>Operando</i> diagnostic detection of interfacial oxygen ‘breathing’ of resistive random access memory by bulk-sensitive hard X-ray photoelectron spectroscopy
摘要： The HfO2-based resistive random access memory (RRAM) is one of the most promising candidates for non-volatile memory applications. The detection and examination of the dynamic behavior of oxygen ions/vacancies are crucial to deeply understand the microscopic physical nature of the resistive switching (RS) behavior. By using synchrotron radiation based, non-destructive and bulk-sensitive hard X-ray photoelectron spectroscopy (HAXPES), we demonstrate an operando diagnostic detection of the oxygen ‘breathing’ behavior at the oxide/metal interface, namely, oxygen migration between HfO2 and TiN during different RS periods. The results highlight the significance of oxide/metal interfaces in RRAM, even in filament-type devices.
关键词： resistive switching,HfO2,HAXPES,RRAM,interface
更新于2025-09-23 15:22:29
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A camera based human computer interaction through virtual keyboard assistant
摘要： Human Computer Interaction has evolved with time and exploited almost all the possible relationships that human can have with computers. The present scenario of using the computer is often inaccessible to people with severe motor impairment, which cannot inhabit the traditional keyboard and mouse, and require another specialized input device. A Camera mouse Human-Computer Interface (HCI) based virtual assistant is designed and planned to be evaluated with 15 subjects and hoped to work for individuals with advanced Amyotrophic Lateral Sclerosis (ALS), all of whom were given tasks to execute through the virtual assistant. In the proposed system, this includes primarily, a virtual keyboard with an embedded Internet browser. The virtual keyboard allows users with movement impairments, basically hand movement issues, to directly interact with the computer. The keyboard has varied functions, apart from just typing; namely, searching anything on google, login to social media and checking emails, text to speech facilities and has a database that holds all the basic helper commands for the person. The camera mouse is software that allows people to interact with the computer by registering any part of their body and then using that part as the pointing device to work on the computer system. The participants of the evaluation will be both, subjects that have knowledge about the HCI interface and those completely new to it. We define additional criteria for unrestricted internet access for evaluation of the presented and future internet browsers, Camera based browser provides unrestricted access and enables free web surfing for individuals with motor impairments. This system improves the subject’s quality of life and provides uninterrupted access for the subject to use the computer.
关键词： Camera,Virtual keyboard,Graphical User Interface,Human computer Interaction
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Human-Machine Interface for Remote Training of Robot Tasks.
摘要： Regardless of their industrial or research application, the streamlining of robot operations is limited by the proximity of experienced users to the actual hardware. Be it massive open online robotics courses, crowd-sourcing of robot task training, or remote research on massive robot farms for machine learning, the need to create an apt remote Human-Machine Interface is quite prevalent. The paper at hand proposes a novel solution to the programming/training of remote robots employing an intuitive and accurate user-interface which offers all the benefits of working with real robots without imposing delays and inefficiency. The system includes: a vision-based 3D hand detection and gesture recognition subsystem, a simulated digital twin of a robot as visual feedback, and the “remote” robot learning/executing trajectories using dynamic motion primitives. Our results indicate that the system is a promising solution to the problem of remote training of robot tasks.
关键词： Human-Machine Interface,Robot Tasks,Hand Detection,Remote Robots,Remote Training,Dynamic Motion Primitives
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Shenzhen, China (2018.6.6-2018.6.8)] 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Characterization of Transient Threshold Voltage Shifts in Enhancement- and Depletion-mode AlGaN/GaN Metal-Insulator-Semiconductor (MIS)-HEMTs
摘要： Both enhancement- and depletion-mode AlGaN/GaN metal-insulator-semiconductor HEMTs were fabricated with Al2O3 as the gate dielectric formed by atomic layer deposition (ALD). With the common problems of threshold voltage hysteresis in AlGaN/GaN MIS-HEMTs, DC I-V and fast transient frequency-dependent C-V measurements were performed to characterize the threshold voltage shifts ?Vth and hence to systematically study the underlying mechanism. The experimental results reveal that ?Vth can be as high as 1.0 V at VG,max = 5 V in transient I-V measurements despite the much lower values of 0.42 V in static and CV measurements. This has significant implications in using AlGaN/GaN MIS-HEMTs for high voltage switching applications. Besides, multi-frequency C-V measurements show that the primary ?Vth is frequency independent but the second onset of voltage shifts (?V2) shows obvious frequency dependence. These results imply the likely mechanism of slow (deep) Al2O3 interface traps accounting for ?V1 hysteresis, and fast (shallow) interface traps accounting for ?V2.
关键词： AlGaN/GaN MIS-HEMT,Al2O3/III-N interface traps (fast and slow) and threshold voltage hysteresis.
更新于2025-09-23 15:21:21
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Accurate <i>ab initio</i> determination of ballistic electron emission spectroscopy: Application to Au/Ge
摘要： Ab initio nonequilibrium Keldysh formalism based on an N -order renormalization technique is used to compute I (V ) ballistic electron emission microscopy characteristics at the Au/Ge(001) interface. Such a formalism quantitatively reproduces precise experimental measurements under ultrahigh vacuum and low-temperature conditions. At T = 0 K, the ballistic current follows the law (V ? VSB)2.1, VSB being the Schottky barrier. At T > 0 K, temperature effects become signi?cant near the onset and must be taken into account to identify an accurate value for VSB from a best-?t procedure. We ?nd two values for VSB, 0.67 and 0.75 eV, which we associate with two different atomic registries at the interface.
关键词： Au/Ge interface,ab initio,nonequilibrium Keldysh formalism,ballistic electron emission microscopy,Schottky barrier
更新于2025-09-23 15:21:21
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Effect of Post Oxide Annealing on the Electrical and Interface 4H-SiC/Al<sub>2</sub>O<sub>3</sub> MOS Capacitors
摘要： This paper reports on the effect of forming gas annealing on the C-V characteristics and stability of Al2O3/SiC MOS capacitors deposited by atomic layer deposition, (ALD). C-V and I-V measurements were performed to assess the quality of the Al2O3 layer and the Al2O3/SiC interface. In comparison to as-deposited sample, the post oxide annealing (POA) in forming gas at high temperatures has improved the stability of C-V characteristic and the properties at the interface of Al2O3/SiC capacitors. However, the oxide capacitance and oxide breakdown electric field degrade with increased annealing temperature. The results provide indications to improve the performance of Al2O3/SiC capacitors 4H-SiC devices by optimizing the annealing temperature.
关键词： forming gas,Al2O3,atomic layer deposition,interface state density,4H-SiC
更新于2025-09-23 15:21:21
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A Fluidic Interface with High Flow Uniformity for Reusable Large Area Resonant Biosensors
摘要： Resonant biosensors are known for their high accuracy and high level of miniaturization. However, their fabrication costs prevent them from being used as disposable sensors and their effective commercial success will depend on their ability to be reused repeatedly. Accordingly, all the parts of the sensor in contact with the ?uid need to tolerate the regenerative process which uses different chemicals (H3PO4, H2SO4 based baths) without degrading the characteristics of the sensor. In this paper, we propose a ?uidic interface that can meet these requirements, and control the liquid ?ow uniformity at the surface of the vibrating area. We study different inlet and outlet channel con?gurations, estimating their performance using numerical simulations based on ?nite element method (FEM). The interfaces were fabricated using wet chemical etching on Si, which has all the desirable characteristics for a reusable biosensor circuit. Using a glass cover, we could observe the circulation of liquid near the active surface, and by using micro-particle image velocimetry (μPIV) on large surface area we could verify experimentally the effectiveness of the different designs and compare with simulation results.
关键词： micro-machining,microengineering,biosensor,?uidic interface,planar ?ow
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) - Interface Control for Enhancing Field Emission Properties from Single-Crystalline Molybdenum Nanopyramid Emitters
摘要： Interface control is an effective way to improve the field emission performance for an existing cold cathode. In this study, a series of pre- and post-treatments have been carried out to reduce the thickness of mid-layer, from over 30 nm to 3 nm, for the single-crystalline molybdenum nanopyramid emitters. Consequently, enhanced field emission properties have been achieved.
关键词： Molybdenum nanopyramid,Single crystalline,Field emission,Interface control
更新于2025-09-23 15:21:21