Article
Physics, Multidisciplinary
A. Schmitt, P. Vallet, D. Mele, M. Rosticher, T. Taniguchi, K. Watanabe, E. Bocquillon, G. Feve, J. M. Berroir, C. Voisin, J. Cayssol, M. O. Goerbig, J. Troost, E. Baudin, B. Placais
Summary: Researchers have achieved a mesoscopic variant of the Schwinger effect in graphene transistors, which involves the creation of matter by electric fields. By conducting transport measurements, they observed universal one-dimensional Schwinger conductance at the pinch-off of the transistors. These findings enhance our understanding of current saturation limits in ballistic graphene and open up new directions for quantum electrodynamic experiments in the laboratory.
Article
Chemistry, Multidisciplinary
Tianzeng Hong, Chan Guo, Yu Zhang, Runze Zhan, Peng Zhao, Baohong Li, Shaozhi Deng
Summary: This study investigates the nucleation and growth mechanism of vertical few-layer graphene (VFLG) on different substrates and finds that the properties of substrates have a significant impact on the initial nucleation and growth of VFLG. The quality of VFLG is less related to the substrate and more influenced by growth conditions. Additionally, the study shows that the conductivity of VFLG is similar on different substrates, but the interfacial contact resistance varies greatly. Stainless-steel substrate is found to be the most favorable for electrical applications.
Article
Chemistry, Multidisciplinary
Aiwei Wang, Jiuzhou Zhao, Ke Chen, Zhenjun Li, Chi Li, Qing Dai
Summary: A single-electron emitter is developed based on a quantized energy level, which offers high temporal and spatial coherence, as well as a large emission current, ideal for atomic-resolution electron probes. By utilizing carbon nanotubes (CNTs) as the emitter, a current of up to 1.5 nA is achieved, thanks to the double barrier structure with a smaller barrier width. The emitter demonstrates high temporal coherence (energy dispersion around 10 meV) and spatial coherence (effective source radius approximately 0.85 nm), providing a highly coherent electron source for simplifying electron optics systems in atomic-resolution electron microscopy and sub-10 nm electron beam lithography.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Girish Rughoobur, Lay Jain, Akintunde Akinwande
Summary: Experimental demonstration of electron transmission through suspended graphene layers with significant increase in current, possibly due to generation of secondary electrons by primary electrons. Monolayer graphene shows highest output current at approximately 90 eV, up to 1.7 times the incident current, offering potential for low-voltage field emission electron sources in less stringent vacuum environments.
Article
Physics, Applied
M. Oleszko, A. Felix, R. Tomala, M. Chaika, W. Strek
Summary: This study investigates the effect of vacuum level on laser induced white emission (LIWE) of graphene foam and compares it with the electric incandescence of tungsten wire. The increase in pressure inside the dynamic vacuum chamber reduces the emission intensity of LIWE, while it has no effect on the emission of the electrically driven tungsten wire. A similar dependency is observed in the case of field emission (FE) of carbon cathodes. This analogy confirms that white emission and FE are coincident processes occurring during laser excitation of graphene foam.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Michael Davidovich, Igor S. Nefedov, Olga E. Glukhova, Michael M. Slepchenkov
Summary: A static model is proposed for calculating tunneling current in vacuum resonant tunneling triodes and tetrodes with control grids. The model allows for the inclusion of one or two grids in the structure, particularly those under the same voltage. It demonstrates the possibility of high current densities up to 10^(13) A/m(2) in structures with double quantum wells.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Tianzeng Hong, Runze Zhan, Yu Zhang, Shaozhi Deng
Summary: This study successfully grew high crystallinity VFLG using a template method, showing excellent field emission performance and current density. It provides a simple and effective method for realizing the pattern growth of VFLG.
Article
Materials Science, Multidisciplinary
Dali Wang, Anqi Hu, Jian-Ping Lv, Guojun Jin
Summary: We investigate the electronic transport properties of a tilted n-p-n junction in monolayer 1T'-MoS2 under a vertical electric field. Our analytical and numerical results demonstrate that the electric field E-z lifts the spin degeneracy of the anisotropic bands in monolayer 1T'-MoS2, leading to electrically tunable valley-and spin-dependent electron retroreflection in the tilted n-p-n junction. We also observe valley-and spin-dependent Klein tunneling in the n-p-n junction when the electric field E-z reaches a critical value E-c, and the incident angle of Klein tunneling depends on the tilt angle of the junction. Furthermore, we find that only spin-up electrons from the K valley can undergo Klein tunneling for a certain specific tilt angle under normal incidence. Our study provides an efficient mechanism to manipulate valley-and spin-dependent electron retroreflection and Klein tunneling in anisotropic tilted Dirac systems.
Article
Multidisciplinary Sciences
Song Jiang, Tomas Neuman, Alex Boeglin, Fabrice Scheurer, Guillaume Schull
Summary: In this study, the intrinsic optoelectronic properties of graphene nanoribbons (GNRs) were explored using a scanning tunneling microscope-based method. By transferring the GNRs onto a partially insulating surface, luminescence quenching effects were prevented and localized dark excitons associated with the topological end states of the GNRs were observed.
Article
Materials Science, Multidisciplinary
R. Eddhib, S. Ayari, A. Hichri, S. Jaziri
Summary: Structural defects can significantly affect the optical response of monolayer materials and lead to the formation of single-photon emitters (SPEs). This study outlines the criteria for enabling single-photon emissions in two-dimensional materials and explores how they can be achieved in atomically thin transition-metal dichalcogenides (TMD). By modeling the effect of defects and using hybrid heterostructures, it is possible to control the radiative lifetime of these emissions.
Article
Chemistry, Physical
Victor Kleshch, Vitali Porshyn, Anton S. Orekhov, Andrey S. Orekhov, Dirk Luetzenkirchen-Hecht, Alexander N. Obraztsov
Summary: Researchers successfully created a stable point electron source composed of a carbon nanowire and a diamond nanotip electrically coupled through a tunnel junction. Using energy spectroscopy analysis, they characterized the electrons released from nanometer-scale carbon heterostructures. The experimental results demonstrate promising characteristics for practical realization of coherent single-electron guns.
Article
Engineering, Electrical & Electronic
Chengke Chen, Binjie Tang, Hui Xu, Jinping Pan, Meiyan Jiang, Xiao Li, Xiaojun Hu
Summary: In this study, a low-pressure annealing treatment was used to enhance the EFE properties of UNCD films without doping. The improved EFE current densities were attributed to the refinement of diamond grains and the formation of a conductive network.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Geosciences, Multidisciplinary
Zhigang Yuan, Yue Dong, Shiyong Huang, Zuxiang Xue, Xiongdong Yu
Summary: We report direct observations of the detailed processes for the acceleration and thermalization of beam electrons in the plasma sheet (PS) of the Earth's magnetotail. The potential of a double layer (DL) structure is found to be mostly consistent with enhancements of the averaged parallel energy of the beam electrons passing through the DL structure, demonstrating that beam electrons are accelerated by the DL structure. Debye-scale parallel electric field turbulences and an increase of the parallel temperature are simultaneously observed, implying that electrostatic parallel turbulences thermalize beam electrons. These observations imply that the DL is a key process controlling the acceleration and thermalization of beam electrons in the PS of the Earth's magnetotail.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Physics, Applied
Bruno Lepetit
Summary: A new time-independent perturbative quantum method was used to quantitatively study electron field emission from two dimensional materials, showing that emission from graphene follows a modified FN law with a low current level mostly resulting from defects in the material. Our study provides insight into the emission mechanism in graphene.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Alexander Voznyakovskii, Georgii Fursei, Aleksei Vozniakovskii, Mikhail Polyakov, Anna Neverovskaya, Ildar Zakirov
Summary: This study presents the results of field electron emission from two-dimensional graphene-like nanostructures synthesized using self-propagating high-temperature synthesis method. It demonstrates the creation of efficient large-area field emitters with low-threshold field emission effect, capable of generating high-current electron beams in pulsed electric fields.
FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES
(2022)
Article
Physics, Fluids & Plasmas
Ying Bin Zhu, Pan Zhao, Mei Yan Liao, Ruo He Yao, L. K. Ang
Summary: This study presents an electron acceleration model based on Bloch surface waves (BSWs), which generates BSWs by depositing a dielectric multilayer on a prism substrate. The research discusses various aspects of the acceleration mechanism, providing an all-optical method for electron acceleration. The model is numerically solved to explain the phenomenon in space and time domain.
PHYSICS OF PLASMAS
(2022)
Article
Engineering, Electrical & Electronic
Yudi Fan, Da Li, Hanzhi Ma, Jiaqi Xing, Yijie Gu, Lay Kee Ang, Er-Ping Li
Summary: This communication proposes an ultrawideband dual-polarized frequency-selective absorber with a tunable reflective notch. The structure consists of a broadband absorber and a tunable lossless frequency-selective surface. The reflective notch can be tuned with varactors and a dc bias. The measured results of the prototype show good agreement with the simulated results.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Zhuoling Jiang, Tong Su, Cherq Chua, L. K. Ang, Chun Zhang, Liemao Cao, Yee Sin Ang
Summary: 2D layered dielectrics provide a compelling approach for designing next-generation compact nanoelectronics. We investigate the interface properties between LaOX and 2D semiconductors MS2 using DFT simulations, revealing large band offsets between 1.12 and 2.40 eV. Based on electron emission model, LaOX is shown to be an excellent companion dielectric for NMOS and PMOS applications with low leakage currents. The presence of interfacial tunneling potential barrier further suppresses the leakage current.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Physics, Applied
Zheng Feng, Dacheng Wang, Caihong Zhang, Song Sun, Xingcheng Xiang, Xiaoqing Jia, Biaobing Jin, Wei Tan
Summary: Active metasurfaces have gained attention for their function switching and wavefront shaping capabilities. This study introduces a new paradigm for controlling metasurfaces by integrating a tunable and programmable spintronic terahertz emitter. Compatibility with conventional materials enables passive metasurfaces to become active, as demonstrated in a quarter-wave plate design. The integration of the spintronic emitter opens possibilities for programmable metasurfaces using spatial light modulators, bridging metasurface and spintronic THz emitter research.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Jeremy Lim, Suraj Kumar, Yee Sin Ang, Lay Kee Ang, Liang Jie Wong
Summary: This study presents a general framework for describing quantum interference processes involving different fundamental particles or quasi-particles. The framework demonstrates that shaping input wavefunctions is a versatile and powerful tool for producing and controlling quantum interference between distinguishable pathways. Two examples of quantum interference enabled by shaping are discussed, including the vanishing of the zero-loss peak by destructive interference and the quantum interference between free electron and atomic spontaneous emission processes. The findings highlight the potential of emerging quantum wave-shaping techniques in enhancing light-matter interactions and other quantum processes.
Article
Physics, Applied
Wei Jie Chan, L. K. Ang, Yee Sin Ang
Summary: Two-dimensional semi-Dirac systems undergo topological phase transitions between insulating, semi-Dirac, and band inversion phases under external modulation. The behavior of quantum transport and shot noise signatures during these transitions is still unknown.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Chun Yun Kee, Yee Sin Ang, Er-Ping Li, L. K. Ang
Summary: This paper revises the Mark-Helfrich law for ultrathin trap-filled dielectrics, proposes a new scaling of current line density, and emphasizes the difference in current flow between strip contact and edge contact geometries. The developed model is important for the characterization of ultrathin dielectrics used in various electronic applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Multidisciplinary
Renji Bian, Guiming Cao, Er Pan, Qing Liu, Zefen Li, Lei Liang, Qingyun Wu, Lay Kee Ang, Wenwu Li, Xiaoxu Zhao, Fucai Liu
Summary: Sliding ferroelectricity associated with interlayer translation is a promising approach for miniaturizing ferroelectric devices. However, the weak polarization limits the performance of sliding ferroelectric transistors, leading to a low on/off ratio and a narrow memory window. To overcome this, we propose a simple strategy to regulate the Schottky barrier in sliding ferroelectric semiconductor transistors based on gamma-InSe, resulting in high performance with a large on/off ratio (106) and a wide memory window (4.5V). Furthermore, the memory window can be modulated by electrostatic doping or light excitation. These findings provide new opportunities for designing novel ferroelectric devices based on emerging sliding ferroelectricity.
Article
Physics, Fluids & Plasmas
L. K. Ang, Yee Sin Ang, Ching Hua Lee
Summary: We present the theory of out-of-plane (or vertical) electron thermal-field emission from two-dimensional (2D) semimetals. We show that the current-voltage-temperature characteristic is well captured by a universal scaling relation applicable for broad classes of 2D semimetals. Our findings reveal that band topologies in two spatial dimension are indistinguishable from each other and bear no special signature in electron emission characteristics. These findings provide theoretical foundations for the design of 2D-material-based vacuum nanoelectronics.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Applied
Hui Zhang, Zheng Feng, Guansong Li, Liang Zhang, Xiaobing Chen, He Bai, Song Sun, Jin Tang, Jine Zhang, Furong Han, Huaiwen Yang, Wei Tan, Yuansha Chen, Fengxia Hu, Jianwang Cai, Liang Guo, Sunmi Shin, Weisheng Zhao, Baogen Shen, Jirong Sun
Summary: Despite intensive research, the mechanism determining the terahertz (THz) emission of ferromagnetic (FM) metallic monolayers remains elusive. In this study, we found solid evidence that the THz emission is dominated by the anomalous Nernst effect (ANE), which is induced by an ultrafast electron temperature gradient, resulting in THz emission. The introduction of a SiO2 buffer layer led to a reversal in the polarity of the THz waveform, further confirming the importance of ANE.
APPLIED PHYSICS REVIEWS
(2023)
Article
Nanoscience & Nanotechnology
Zipei Zhang, Sitong Luo, Lu Yu, Sitong Wei, Zhen Ji, Wenhao Li, Lay Kee Ang, Shuqi Zheng
Summary: Optimizing thermoelectric materials' performance by reducing thermal conductivity is crucial for enhancing thermoelectric efficiency. This paper demonstrates that the introduction of AgCl can influence the thermal conductivity of CuGaTe2. The introduction of AgCl decreases the thermal conductivity of CuGaTe2 while maintaining good electrical properties, resulting in an ultra-high ZT value of 1.4 at 823 K for the (CuGaTe2)0.96(AgCl)0.04 sample.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Nam Thanh Trung Vu, Leyi Loh, Yuan Chen, Qingyun Wu, Ivan A. A. Verzhbitskiy, Kenji Watanabe, Takashi Taniguchi, Michel Bosman, Yee Sin Ang, Lay Kee Ang, Maxim Trushin, Goki Eda
Summary: Precisely controlled impurity doping is essential in modern semiconductor technologies, and desired properties can be achieved at very low concentrations. However, in two-dimensional semiconductors, the identification and quantification of impurities are challenging due to their dilute limit and the limitations of common analytical techniques. In this study, we utilize conductive atomic force microscopy to rapidly and accurately image dilute single atomic impurities. The local conductivity is enhanced by more than 100-fold due to resonance-assisted tunneling, and the imaging is selective for minority defects. We also demonstrate the detection of subsurface impurities with single monolayer depth resolution in multilayer materials.
Article
Physics, Fluids & Plasmas
Wei Jie Chan, Cherq Chua, Yee Sin Ang, Lay Kee Ang
Summary: This article reviews recent experimental studies on field emission in two-dimensional materials and summarizes and compares their emission characteristics. The importance of establishing consistent physics-based models to understand field emission from these quantum materials is emphasized, and possible future research directions are highlighted.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2023)
Article
Optics
Weifang Yang, L. K. Ang, Wentao Zhang, Jiaguang Han, Yi Xu
Summary: In this paper, the sub-wavelength transverse displacement of photonic spin Hall effect (PSHE) is significantly enhanced by the surface exciton polariton (SEP) for application in gas sensing. The transverse displacement of 14.4 times the wavelength of incident light is achieved with the SEP enhanced PSHE, which is about 3 times that of surface plasmon resonance enhanced PSHE. A gas sensor based on SEP enhanced PSHE is proposed for the detection of SO2, and the refractive index sensitivity of 6320.4 μm/RIU is obtained in the refractive index range from 1.00027281 to 1.00095981. These results undoubtedly demonstrate SEP to be a promising mechanism for PSHE enhancement, and open up new opportunities for highly sensitive gas sensing, biosensing, and chemical sensing.
Article
Nanoscience & Nanotechnology
Yew Von Lim, Sareh Vafakhah, Xue Liang Li, Zhuoling Jiang, Daliang Fang, Shaozhuan Huang, Ye Wang, Yee Sin Ang, Lay Kee Ang, Hui Ying Yang
Summary: This study involves a synthetic-based approach to improve the utilization and activation of active materials in lithium-sulfur batteries. By incorporating conductive, low-dimensional carbonaceous composites as containment hosts and catalysts, the issues of low activation, poor conductivity, and side reactions are effectively addressed. The use of CoS-based carbonaceous composites as catalysts enhances performance and alleviates side reactions. The results demonstrate high stability, strong polysulfide adsorption capability, large and workable areal capacity, and active materials loading.
