Yang Xu

Zhejiang University, School of Micro-Nano Electronics, Faculty Member

Zhejiang University, Isee, Faculty Member

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Prof. Yang Xu is an IEEE NTC Distinguished Lecturer, Fellow of the Institute of Physics (FInstP, IOP Fellow), Fellow of Royal Society of Chemistry (FRSC), Fellow of the Institute of Materials, Minerals and Mining (FIMMM), Fellow of Institute of Engineering and Technology (FIET) , and IEEE Senior Member of the Electron Devices Society. He received his B.S. degree in Institute of Microelectronics at Department of ECE from Tsinghua University, M.S. and Ph.D. degrees in ECE from the University of Illinois Urbana-Champaign (UIUC), USA. He is now a full professor at the School of Micro-Nano Electronics, Zhejiang University, China. He was also a visiting by-Fellow of Churchill College at the University of Cambridge, UK, and a visiting professor at the University of California Los Angles (UCLA). He has published more than 120 papers including Nature Nanotechnology, Nature Electronics, Nature Photonics, Chemical Reviews, Advanced Materials, Chemical Society Reviews, Nature Communications, Nano Letters, ACS Nano, and IEDM. He holds over 30 granted patents and gave more than 50 talks in international conferences. He is also served as Associate Editor of IEEE T-ED, IEEE Nanotechnology Magazine, Photonics Research, Nanotechnology, and was TPC committee members of IEEE-EDTM, IEEE-IPFA, and IEEE-EDAPS conferences. His research interests include emerging 2D/3D integrated optoelectronic devices for Internet-of-Things and Post-Moore Ubiquitous Electronics.
Supervisors: Advisors of PhDs and Postdocs, Full Professor, and We are hiring excellent postdocs now, please feel free to contact us.

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A VERSATILE AND ENVIRONMENTALLY FRIENDLY MICROFABRICATION PROCESS FOR PRODUCING MICRO-BASIN ARRAY FOR SINGLE CELL ANALYSIS

2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS) (2021).DOI:10.1109/MEMS51782.2021.9375448 , 2021

This paper reports a low-cost and versatile micro-basin array fabrication approach for single mam... more This paper reports a low-cost and versatile micro-basin array fabrication approach for single mammalian cell and single bacterial analysis. This approach is based on optical lithography, material sputtering, and lift off. The pitch, size, height, thickness, inclination angle and material type of the micro-basins can be adjusted controllably. The whole fabrication process does not require any strong chemical etching process and is environmentally friendly and costeffective. Finite element analysis was applied to obtain optimal dimensions of micro-basins. Preliminary results show successful isolation of single bacterium within microbasins. Ongoing work focuses on improving the isolation efficiency through hydrophobic and hydrophilic patterning.

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Twist angle dependent absorption feature induced by interlayer rotations in CVD bilayer graphene

Nanophotonics, 2021

Bilayer graphene (BLG) grown via chemical vapor deposition (CVD) tends to exhibit twisted stackin... more Bilayer graphene (BLG) grown via chemical vapor deposition (CVD) tends to exhibit twisted stacking. The twist angle θ t in twisted BLG (tBLG) provides a new degree of freedom for engineering its electronic and optical properties. In this paper, we investigate the θ t-dependent optical absorption in tBLG and deeply understand the electronic structure-optical properties correlations. New absorption peaks, whose wavelengths are modified by θ t , are observed on the feature of optical contrast (OC) in tBLG. Under the corresponding energy excitation, the Raman G mode in tBLG exhibits a significant enhancement. Furthermore, the results of θ t obtained by OC absorption peak are verified to be consistent with those by the Raman R mode. All these properties are proved to be related to the energy difference between low-energy Van Hove singularities (E VHS) in the density of states of tBLGs. This work builds a relation between optical absorption and twist angle, providing a viable method to identifying twist angles in tBLGs.

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Macroscopic-Assembled-Graphene Nanofilms/Germanium Broadband Photodetectors

2021 IEEE International Electron Devices Meeting (IEDM), 2021

Germanium (Ge) based devices are widely used in optical communications and image sensors due to t... more Germanium (Ge) based devices are widely used in optical communications and image sensors due to the brilliant properties of Ge (high carrier mobility, excellent CMOS compatibility). Here, by integrating Ge with the nanofilms of macroscopic-assembled-graphene (nMAG)-large-scale highly crystalline graphene nanofilm, we demonstrated a highperformance Schottky diode. The device shows a detection bandwidth of 1.5 to 4 μm with responsivities ranging from 1.1 A/W to 40 mA/W and specific detectivity between 10 11 to 10 9 Jones, and a rising time of ~80 ns at room temperature. Such performance is a result of the broadband and strong absorption, the long carrier relaxation time (20 ps) of nMAG, and the low Schottky barrier of nMAG/Ge junction. The broadband detection range of this detector is comparable to the state-ofthe-art Ge-based IR photodiodes.

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2D Heterostructures for Ubiquitous Electronics and Optoelectronics: Principles, Opportunities, and Challenges

Chemical Reviews, 2022

A grand family of two-dimensional (2D) materials and their heterostructures have been discovered ... more A grand family of two-dimensional (2D) materials and their heterostructures have been discovered through the extensive experimental and theoretical efforts of chemists, material scientists, physicists, and technologists. These pioneering works contribute to realizing the fundamental platforms to explore and analyze new physical/chemical properties and technological phenomena at the micro−nano−pico scales. Engineering 2D van der Waals (vdW) materials and their heterostructures via chemical and physical methods with a suitable choice of stacking order, thickness, and interlayer interactions enable exotic carrier dynamics, showing potential in high-frequency electronics, broadband optoelectronics, lowpower neuromorphic computing, and ubiquitous electronics. This comprehensive review addresses recent advances in terms of representative 2D materials, the general fabrication methods, and characterization techniques and the vital role of the physical parameters affecting the quality of 2D heterostructures. The main emphasis is on 2D heterostructures and 3D-bulk (3D) hybrid systems exhibiting intrinsic quantum mechanical responses in the optical, valley, and topological states. Finally, we discuss the universality of 2D heterostructures with representative applications and trends for future electronics and optoelectronics (FEO) under the challenges and opportunities from physical, nanotechnological, and material synthesis perspectives.

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Macroscopic assembled graphene nanofilms based room temperature ultrafast mid-infrared photodetectors

InfoMat, 2022

Graphene with linear energy dispersion and weak electron-phonon interaction is highly anticipated... more Graphene with linear energy dispersion and weak electron-phonon interaction is highly anticipated to harvest hot electrons in a broad wavelength range. However, the limited absorption and serious backscattering of hot-electrons result in inadequate quantum yields, especially in the mid-infrared range. Here, we report a macroscopic assembled graphene (nMAG) nanofilm/silicon heterojunction for ultrafast mid-infrared photodetection. The assembled Schottky diode works in 1.5-4.0 μm at room temperature with fast response (20-30 ns, rising time, 4 mm 2 window) and high detectivity (1.6 Â 10 11 to 1.9 Â 10 9 Jones from 1.5 to 4.0 μm) under the pulsed laser, outperforming single-layer-graphene/silicon photodetectors by 2-8 orders. These performances are attributed to the greatly enhanced Li Peng and Lixiang Liu contributed equally to this work.

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Graphene charge injection photodetectors

Nature Electronics, 2022

Charge-coupled devices are widely used imaging technologies. However, their speed is limited due ... more Charge-coupled devices are widely used imaging technologies. However, their speed is limited due to the complex readout process, which involves sequential charge transfer between wells, and their spectral bandwidth is limited due to the absorption limitations of silicon. Here we report graphene charge-injection photodetectors. The devices have a deep-depletion silicon well for charge integration, single-layer graphene for non-destructive direct readout and multilayer graphene for infrared photocharge injection. The photodetectors offer broadband imaging from ultraviolet (around 375 nm) to mid-infrared (around 3.8 μm), a conversion gain of 700 pA per electron, a responsivity above 0.1 A W−1 in the infrared region and a fast response time under 1 μs.

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Intralayer Phonons in Multilayer Graphene Moiré Superlattices

Research, 2022

Moiré pattern in twisted multilayers (tMLs) induces many emergent phenomena by subtle variation o... more Moiré pattern in twisted multilayers (tMLs) induces many emergent phenomena by subtle variation of atomic registry to modulate quasiparticles and their interactions, such as superconductivity, moiré excitons, and moiré phonons. The periodic superlattice potential introduced by moiré pattern also underlies patterned interlayer coupling at the interface of tMLs. Although this arising patterned interfacial coupling is much weaker than in-plane atomic interactions, it is crucial in moiré systems, as captured by the renormalized interlayer phonons in twisted bilayer transitional metal dichalcogenides. Here, we determine the quantitative relationship between the lattice dynamics of intralayer out-of-plane optical (ZO) phonons and patterned interfacial coupling in multilayer graphene moiré superlattices (MLG-MS) by the proposed perturbation model, which is previously challenging for MLGs due to their out-of-phase displacements of adjacent atoms in one atomic plane. We unveil that patterned interfacial coupling introduces profound modulations on Davydov components of nonfolded ZO phonon that are localized within the AB-stacked constituents, while the coupling results in layer-extended vibrations with symmetry of moiré pattern for moiré ZO phonons. Our work brings further degrees of freedom to engineer moiré physics according to the modulations imprinted on the phonon frequency and wavefunction.

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Two-dimensional ferroelectricity and antiferroelectricity for next-generation computing paradigms

by Yang Xu and Fei Xue

Matter, 2022

Ferroelectricity (FE) and antiferroelectricity (AFE) are correlated physical phenomena that, in t... more Ferroelectricity (FE) and antiferroelectricity (AFE) are correlated physical phenomena that, in the two-dimensional (2D) limit, exhibit unprecedented rich physics in terms of polarization creation, stabilization, and switching. By modulating the proximity effect of polarization, 2D FE and AFE can unexpectedly demonstrate reversible transformations. Moreover, these fundamental physics can spur innovation in memory devices toward emerging computation paradigms, including neuromorphic computing and sensing. In this perspective, we discuss the emergent physics of 2D FE and AFE and highlight phase transitions with different approaches between them. We also outline advanced device applications for next-generation computing and provide possible future research lines.

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High-performance silicon photonic filters based on all-passive tenth-order adiabatic elliptical-microrings

APL Photonics, 2022

Ultra-compact silicon photonic filters with box-like responses and high extinction ratios are pro... more Ultra-compact silicon photonic filters with box-like responses and high extinction ratios are proposed and demonstrated by introducing tenth-order adiabatic elliptical-microrings (AEMs) with bent directional couplers. For the AEMs, the waveguides in the non-coupling regions are wide and have a minimal bending radius, while the waveguides in the coupling regions are narrowed and have a maximal bending radius. The present silicon photonic filters based on tenth-order AEMs show a free spectral range as large as 37 nm for the first time. Even fabricated with commercial complementary metal-oxide-semiconductor-compatible 248 nm deep-ultraviolet lithography processes, the present devices show high performances with excess losses as low as ∼1 dB and extinction ratios as high as >60 dB. More importantly, the present silicon photonic filters work very well all-passively without any thermal control for calibration.

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Defect-induced photocurrent gain for carbon nanofilm-based broadband infrared photodetector

Carbon, 2022

Broad-spectrum detection and large-scale integration are the inevitable trends in the current evo... more Broad-spectrum detection and large-scale integration are the inevitable trends in the current evolution of infrared photodetectors. New materials were integrated with existing platforms to further improve the performance of infrared photodetectors. Here, we reported a defective macro-assembled graphene nanofilm (D-nMAG)/Silicon (Si) photodetector using trap-assisted gain to optimize the photoelectric response. This waferscale environmentally friendly carbon material can be easily compatible with the complementary-metal-oxidesemiconductor (CMOS) technical. Noteworthy, the defective states in D-nMAG trap carriers and then enter the conduction (CB) and valence band (VB) again to be thermalized, generating a gain in photocurrent. Thus, our D-nMAG-based line array image sensor exhibits high-resolution infrared imaging of the target. This device displays a high responsivity at room temperature within a broad-spectrum region, i.e., 0.156 A/W @ 900 nm in the nearinfrared (NIR) region and 3.7 mA/W @ 4 μm in the mid-infrared (MIR) region. Our work provides a carbon nanofilm for IR detection at a broad-spectrum region, with tunable defective structure, uniform thickness, and wafer-scale production.

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Graphene Nanofilms/Silicon Near-Infrared Avalanche Photodetectors

by Yang Xu, Xinyu Liu, and Xiaochen Wang

IEEE Transactions on Nanotechnology, 2022

Graphene/silicon Schottky junction diodes have been extensively studied and widely used in photod... more Graphene/silicon Schottky junction diodes have been extensively studied and widely used in photodetection. However, limited to the low light absorption of single-layer graphene and bandgap of silicon, graphene/silicon devices exhibit low quantum efficiency in the infrared region. Here, we demonstrate a highperformance near-infrared Schottky diode by integrating silicon with the macroscopic assembled graphene nanofilms (nMAG). Because of the intense light absorption, low work function, and long carrier lifetime of nMAG, the device shows a detection spectra range up to 1870 nm with the responsivity of 0.4 mA/W and response speed of 371 ns. By driving the device into avalanche multiplication, 10 4-10 5 of avalanche gain has been obtained, and the responsivity at 1870 nm increases to 10 A/W. The device structure in this report could be compatible with the semiconductor process so that silicon-based infrared photodetectors with high performance and low cost could be potentially realized.

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Neuromorphic device based on silicon nanosheets

Nature Communications, 2022

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Charge Sampling Photodetector Based on van der Waals Heterostructures

by Yang Xu and Xiaomu Wang

Advanced Optical Materials, 2022

advantages of low cost and high speed due to its simple fabrication process, low power consumptio... more advantages of low cost and high speed due to its simple fabrication process, low power consumption, and random-access readout, thus occupying the majority of current commercial markets. [1-3] In comparison, the CCD image sensor, outperforms the CMOS image sensor in terms of imaging fidelity owing to its high fill factor, high sensitivity, and low noise. [4]

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A super high aspect ratio atomic force microscopy probe for accurate topography and surface tension measurement

by Yang Xu and Zhibin Wang

Sensors and Actuators A: Physical, 2022

This work presents a methodology for fabricating high aspect ratio atomic force microscopy (HAR-A... more This work presents a methodology for fabricating high aspect ratio atomic force microscopy (HAR-AFM) probes and its applications in high aspect ratio nanostructure topography and liquid surface tension measurement. The focus ion beam (FIB) precisely positions and grows HAR tips of controlled diameter, height, and tilting angle, which can fabricate robust, repeatable, and multi-angled HAR tips. Through ion beam etching, the probe tip was further sharpened, which helped to achieve a high resolution of topography scanning. We achieved HAR probes fabrication with an aspect ratio of 5-40, a maximum height of 20 µm, a minimum diameter of less than 100 nm, and a tilting angle range of 0-15 •. The actual superior performance of FIB-fabricated probes is demonstrated by observing the topography of nano-trenches by HAR AFM probes and compared with commercial pyramid-shaped AFM probes. An additional application is demonstrated that surface tension of micron/nanodroplets could be measured accurately by HAR AFM probes.

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Multi-Stimuli-Responsive Synapse Based on Vertical van der Waals Heterostructures

ACS Appl. Mater. Interfaces, 2022

Brain-inspired intelligent systems demand diverse neuromorphic devices beyond simple functionalit... more Brain-inspired intelligent systems demand diverse neuromorphic devices beyond simple functionalities. Merging biomimetic sensing with weight-updating capabilities in artificial synaptic devices represents one of the key research focuses. Here, we report a multiresponsive synapse device that integrates synaptic and optical-sensing functions. The device adopts vertically stacked graphene/h-BN/WSe 2 heterostructures, including an ultrahighmobility readout layer, a weight-control layer, and a dual-stimuliresponsive layer. The unique structure endows synapse devices with excellent synaptic plasticity, short response time (3 μs), and excellent optical responsivity (10 5 A/W). To demonstrate the application in neuromorphic computing, handwritten digit recognition was simulated based on an unsupervised spiking neural network (SNN) with a precision of 90.89%, well comparable with the state-of-the-art results. Furthermore, multiterminal neuromorphic devices are demonstrated to mimic dendritic integration and photoswitching logic. Different from other synaptic devices, the research work validates multifunctional integration in synaptic devices, supporting the potential fusion of sensing and self-learning in neuromorphic networks.

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Bio-Inspired Hierarchical Micro-/Nanostructures for Anti-Icing Solely Fabricated by Metal-Assisted Chemical Etching

Micromachines, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more

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Determining layer number of micro-mechanical exfoliated and CVD grown ultrathin graphenes by the methods of Raman intensity ratio

Optik, 2022

How to determine layer number (N) of graphene materials is of primary importance for practical ap... more How to determine layer number (N) of graphene materials is of primary importance for practical applications. In this work, with 532 nm and 633 nm excitation wavelengths, we used the methods of Raman intensity ratio to identify the layers (N ≤ 4) of ultrathin graphenes prepared by micromechanical exfoliation and chemical vapor deposition (CVD). We also analyzed the effects of excitation wavelength and sample preparation method on identification of N. The following results were obtained. The intensity ratio of G mode from graphenes and Si mode from substrate underneath graphenes (I(G)/I G (Si)) increases monotonically with the increase of N, which is affected not only by excitation wavelength but also by sample preparation method. However, the intensity ratio of Si mode from substrate underneath graphenes and Si mode from bare substrate (I G (Si)/I 0 (Si)) decreases monotonically with the increase of N, which is only affected by excitation wavelength but almost not affected by sample preparation method. By contrast, the I G (Si)/I 0 (Si) method using 532 nm laser is a good option for N identification of 1LG-4LG whether the sample preparation method is micro-mechanical exfoliation or CVD.

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Broadband Graphene Field-Effect Coupled Detectors: From Soft X-Ray to Near-Infrared

IEEE Electron Device Letters, 2022

Here, we report a broadband graphene-silicon field-effect coupled detector (FCD) sensitive to pho... more Here, we report a broadband graphene-silicon field-effect coupled detector (FCD) sensitive to photons spanning from soft X-ray to Near-Infrared region. Unlike traditional charge-coupled devices (CCD) relying on serial charge transfer between potential wells, the FCD integrates photo-sensing, charge integration, field-effect amplification, and random readout in one pixel. The charge integration in the potential well of the semiconductor substrate and field-effect coupled amplification in graphene transistor result in a highly sensitive broadband response. In the X-ray region, the device displays a high sensitivity of 1088 CGy air −1 cm −2 and a fast response time <∼5 ms. Linear array imaging reveals the potential of our devices for array-based broadband imaging. Our FCD offers a viable strategy to monolithically integrate 2D materials into conventional solid-state imaging technology, exploring the next-generation broadband photodetectors for high-quality imaging and super vision technology.

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Graphene photonic crystal fiber with large modulation depth

Science China Chemistry, 2020

Figure 1 (a) Schematics of graphene photonic crystal fibers grown by the CVD method; (b) schemati... more Figure 1 (a) Schematics of graphene photonic crystal fibers grown by the CVD method; (b) schematics of graphene growth on the walls of the micrometer size holes of PCF with LPCVD; (c) schematic of a Gr-PCF-based electro-optic modulator; (d) 2D mapping of transmission modulation (normalized by fibre length) of the Gr-PCF modulator as a function of gate voltage and optical wavelength (color online).

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High-performance silicon−graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm

Light: Science & Applications, 2020

Graphene has attracted much attention for the realization of high-speed photodetection for silico... more Graphene has attracted much attention for the realization of high-speed photodetection for silicon photonics over a wide wavelength range. However, the reported fast graphene photodetectors mainly operate in the 1.55 μm wavelength band. In this work, we propose and realize high-performance waveguide photodetectors based on bolometric/photoconductive effects by introducing an ultrathin wide silicon−graphene hybrid plasmonic waveguide, which enables efficient light absorption in graphene at 1.55 μm and beyond. When operating at 2 μm, the present photodetector has a responsivity of~70 mA/W and a setup-limited 3 dB bandwidth of >20 GHz. When operating at 1.55 μm, the present photodetector also works very well with a broad 3 dB bandwidth of >40 GHz (setup-limited) and a high responsivity of~0.4 A/W even with a low bias voltage of −0.3 V. This work paves the way for achieving highresponsivity and high-speed silicon-graphene waveguide photodetection in the near/mid-infrared ranges, which has applications in optical communications, nonlinear photonics, and on-chip sensing.

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A VERSATILE AND ENVIRONMENTALLY FRIENDLY MICROFABRICATION PROCESS FOR PRODUCING MICRO-BASIN ARRAY FOR SINGLE CELL ANALYSIS

2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS) (2021).DOI:10.1109/MEMS51782.2021.9375448 , 2021

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Twist angle dependent absorption feature induced by interlayer rotations in CVD bilayer graphene

Nanophotonics, 2021

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Macroscopic-Assembled-Graphene Nanofilms/Germanium Broadband Photodetectors

2021 IEEE International Electron Devices Meeting (IEDM), 2021

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2D Heterostructures for Ubiquitous Electronics and Optoelectronics: Principles, Opportunities, and Challenges

Chemical Reviews, 2022

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Macroscopic assembled graphene nanofilms based room temperature ultrafast mid-infrared photodetectors

InfoMat, 2022

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Graphene charge injection photodetectors

Nature Electronics, 2022

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Intralayer Phonons in Multilayer Graphene Moiré Superlattices

Research, 2022

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Two-dimensional ferroelectricity and antiferroelectricity for next-generation computing paradigms

by Yang Xu and Fei Xue

Matter, 2022

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High-performance silicon photonic filters based on all-passive tenth-order adiabatic elliptical-microrings

APL Photonics, 2022

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Defect-induced photocurrent gain for carbon nanofilm-based broadband infrared photodetector

Carbon, 2022

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Graphene Nanofilms/Silicon Near-Infrared Avalanche Photodetectors

by Yang Xu, Xinyu Liu, and Xiaochen Wang

IEEE Transactions on Nanotechnology, 2022

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Neuromorphic device based on silicon nanosheets

Nature Communications, 2022

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Charge Sampling Photodetector Based on van der Waals Heterostructures

by Yang Xu and Xiaomu Wang

Advanced Optical Materials, 2022

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A super high aspect ratio atomic force microscopy probe for accurate topography and surface tension measurement

by Yang Xu and Zhibin Wang

Sensors and Actuators A: Physical, 2022

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Multi-Stimuli-Responsive Synapse Based on Vertical van der Waals Heterostructures

ACS Appl. Mater. Interfaces, 2022

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Bio-Inspired Hierarchical Micro-/Nanostructures for Anti-Icing Solely Fabricated by Metal-Assisted Chemical Etching

Micromachines, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more

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Determining layer number of micro-mechanical exfoliated and CVD grown ultrathin graphenes by the methods of Raman intensity ratio

Optik, 2022

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Broadband Graphene Field-Effect Coupled Detectors: From Soft X-Ray to Near-Infrared

IEEE Electron Device Letters, 2022

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Graphene photonic crystal fiber with large modulation depth

Science China Chemistry, 2020

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High-performance silicon−graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm

Light: Science & Applications, 2020

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A self-powered high-performance graphene/silicon ultraviolet photodetector with ultra-shallow junction: breaking the limit of silicon?.

npj 2d materials and applications, 2017

We present a self-powered, high-performance graphene-enhanced ultraviolet silicon Schottky photod... more We present a self-powered, high-performance graphene-enhanced ultraviolet silicon Schottky photodetector. Different from traditional transparent electrodes, such as indium tin oxides or ultra-thin metals, the unique ultraviolet absorption property of graphene leads to long carrier life time of hot electrons that can contribute to the photocurrent or potential carrier-multiplication. Our proposed structure boosts the internal quantum efficiency over 100%, approaching the upper-limit of silicon-based ultraviolet photodetector. In the near-ultraviolet and mid-ultraviolet spectral region, the proposed ultraviolet photodetector exhibits high performance at zero-biasing (self-powered) mode, including high photo-responsivity (0.2 A W −1
−1
), fast time response (5 ns), high specific detectivity (1.6 × 10 13
13
Jones), and internal quantum efficiency greater than 100%. Further, the photo-responsivity is larger than 0.14 A W −1
−1
in wavelength range from 200 to 400 nm, comparable to that of state-of-the-art Si, GaN, SiC Schottky photodetectors. The photodetectors exhibit stable operations in the ambient condition even 2 years after fabrication, showing great potential in practical applications, such as wearable devices, communication, and “dissipation-less” remote sensor networks.

Negative Differential Resistances Observed In Suspended‐Channel FETs

AIP Conference Proceedings, 2011

A new type of negative differential resistance (NDR) device based on the electro‐mechanical princ... more A new type of negative differential resistance (NDR) device based on the electro‐mechanical principle, named suspended‐channel FET (SC‐FET), is proposed. The FET channel is built up on a suspended nano‐bridge. When voltages are applied between the bridge and the substrate, the channel together with the bridge is pulled towards the substrate. The output and transfer characteristics of the SC‐FET are influenced by the vertical displacement and uniaxial strain near the channel. NDR is observed in the saturation region, which can be explained by an electromechanical coupling model.

Quantum Squeezing Effects of Monolayer Graphene NEMS

AIP Conference Proceedings, 2011

Quantum mechanical limit governed by Heisenberg uncertainty relation decides the ultimate precisi... more Quantum mechanical limit governed by Heisenberg uncertainty relation decides the ultimate precision of nanomechanical systems. Quantum squeezing can improve the precision by reducing quantum fluctuations in one desired amplitude of the two quadrature amplitudes. Traditional nanoelectromechanical systems (NEMS) hardly achieve quantum squeezing due to their thickness limits. We propose a scheme to obtain squeezed quantum states through typical experimental graphene NEMS structures taking advantages of its atomic scale thickness. The zero‐point displacement uncertainty Δxzp and quantum squeezing factor R of graphene NEMS have been studied.

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