scholarly journals Quantum plasmonic control of trions in a picocavity with monolayer WS2

2019 ◽  
Vol 5 (10) ◽  
pp. eaau8763 ◽  
Author(s):  
Zhe He ◽  
Zehua Han ◽  
Jiangtan Yuan ◽  
Alexander M. Sinyukov ◽  
Hichem Eleuch ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Hot Spots ◽  
High Performance ◽  
2D Materials ◽  
Spatial Location ◽  
Scanning Probe ◽  
Field Techniques ◽  
Enhanced Photoluminescence ◽  
Charged Exciton ◽  
Charge Tunneling

Monitoring and controlling the neutral and charged excitons (trions) in two-dimensional (2D) materials are essential for the development of high-performance devices. However, nanoscale control is challenging because of diffraction-limited spatial resolution of conventional far-field techniques. Here, we extend the classical tip-enhanced photoluminescence based on tip-substrate nanocavity to quantum regime and demonstrate controlled nano-optical imaging, namely, tip-enhanced quantum plasmonics. In addition to improving the spatial resolution, we use the scanning probe to control the optoelectronic response of monolayer WS2 by varying the neutral/charged exciton ratio via charge tunneling in Au-Ag picocavity. We observe trion “hot spots” generated by varying the picometer-scale probe-sample distance and show the effects of weak and strong coupling, which depend on the spatial location. Our experimental results are in agreement with simulations and open an unprecedented view of a new range of quantum plasmonic phenomena with 2D materials that will help to design new quantum optoelectronic devices.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Co-planar two-dimensional Metal-Insulator-Semiconductor Capacitor: Numerical study of the device electrostatics.

2017 ◽  
Author(s):  
Varun Bheemireddy
Keyword(s):  
Space Charge ◽  
High Performance ◽  
Numerical Study ◽  
2D Materials ◽  
Space Charge Density ◽  
Two Dimensional ◽  
Short Channel ◽  
Metal Insulator ◽  
Metal Insulator Semiconductor ◽  
New Family

The two-dimensional(2D) materials are highly promising candidates to realise elegant and e cient transistor. In the present letter, we conjecture a novel co-planar metal-insulator-semiconductor(MIS) device(capacitor) completely based on lateral 2D materials architecture and perform numerical study of the capacitor with a particular emphasis on its di erences with the conventional 3D MIS electrostatics. The space-charge density features a long charge-tail extending into the bulk of the semiconductor as opposed to the rapid decay in 3D capacitor. Equivalently, total space-charge and semiconductor capacitance densities are atleast an order of magnitude more in 2D semiconductor. In contrast to the bulk capacitor, expansion of maximum depletion width in 2D semiconductor is observed with increasing doping concentration due to lower electrostatic screening. The heuristic approach of performance analysis(2D vs 3D) for digital-logic transistor suggest higher ON-OFF current ratio in the long-channel limit even without third dimension and considerable room to maximise the performance of short-channel transistor. The present results could potentially trigger the exploration of new family of co-planar at transistors that could play a signi significant role in the future low-power and/or high performance electronics.<br>

scholarly journals Ultrafast mode-locking in highly stacked Ti3C2Tx MXenes for 1.9-μm infrared femtosecond pulsed lasers

Nanophotonics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1741-1751
Author(s):  
Young In Jhon ◽  
Jinho Lee ◽  
Young Min Jhon ◽  
Ju Han Lee
Keyword(s):  
High Performance ◽  
Density Functional ◽  
2D Materials ◽  
Density Functional Theory Calculations ◽  
Mode Locking ◽  
Infrared Range ◽  
Saturable Absorption ◽  
Pulsed Lasers ◽  
Saturable Absorbers ◽  
Layer Stacking

Abstract Metallic 2D materials can be promising saturable absorbers for ultrashort pulsed laser production in the long wavelength regime. However, preparing and manipulating their 2D structures without layer stacking have been nontrivial. Using a combined experimental and theoretical approach, we demonstrate here that a metallic titanium carbide (Ti3C2Tx), the most popular MXene 2D material, can have excellent nonlinear saturable absorption properties even in a highly stacked state due to its intrinsically existing surface termination, and thus can produce mode-locked femtosecond pulsed lasers in the 1.9-μm infrared range. Density functional theory calculations reveal that the electronic and optical properties of Ti3C2Tx MXene can be well preserved against significant layer stacking. Indeed, it is experimentally shown that 1.914-μm femtosecond pulsed lasers with a duration of 897 fs are readily generated within a fiber cavity using hundreds-of-layer stacked Ti3C2Tx MXene saturable absorbers, not only being much easier to manufacture than mono- or few-layered ones, but also offering character-conserved tightly-assembled 2D materials for advanced performance. This work strongly suggests that as-obtained highly stacked Ti3C2Tx MXenes can serve as superb material platforms for versatile nanophotonic applications, paving the way toward cost-effective, high-performance photonic devices based on MXenes.

Controllable Synthesis of Ultrathin Layered Transition Metallic Hydroxide/Zeolitic Imidazolate Framework-67 Hybrid Nanosheets for High-Performance Supercapacitors

2021 ◽  
Author(s):  
Chunli Liu ◽  
Yang Bai ◽  
Ji Wang ◽  
Ziming Qiu ◽  
Huan Pang
Keyword(s):  
Charge Transfer ◽  
Energy Conversion ◽  
High Performance ◽  
2D Materials ◽  
Two Dimensional ◽  
Controllable Synthesis ◽  
Zeolitic Imidazolate Framework ◽  
Fast Charge ◽  
Energy Conversion And Storage ◽  
And Storage

Two-dimensional (2D) materials with structures having diverse features are promising for application in energy conversion and storage. A stronger layered orientation can guarantee fast charge transfer along the 2D planes...

Measurement accuracy and Cerenkov removal for high performance, high spatial resolution scintillation dosimetry

2005 ◽  
Vol 33 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Louis Archambault ◽  
A. Sam Beddar ◽  
Luc Gingras ◽  
René Roy ◽  
Luc Beaulieu
Keyword(s):  
Spatial Resolution ◽  
High Performance ◽  
Measurement Accuracy ◽  
High Spatial Resolution

scholarly journals An ultrahigh-resolution soft x-ray microscope for quantitative analysis of chemically heterogeneous nanomaterials

2020 ◽  
Vol 6 (51) ◽  
pp. eabc4904
Author(s):  
David A. Shapiro ◽  
Sergey Babin ◽  
Richard S. Celestre ◽  
Weilun Chao ◽  
Raymond P. Conley ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Performance ◽  
Ultrahigh Resolution ◽  
High Brightness ◽  
X Ray ◽  
Correlative Analysis ◽  
Scanning Transmission ◽  
Chemical States ◽  
Scanning Mechanism ◽  
Performance Computing

The analysis of chemical states and morphology in nanomaterials is central to many areas of science. We address this need with an ultrahigh-resolution scanning transmission soft x-ray microscope. Our instrument provides multiple analysis tools in a compact assembly and can achieve few-nanometer spatial resolution and high chemical sensitivity via x-ray ptychography and conventional scanning microscopy. A novel scanning mechanism, coupled to advanced x-ray detectors, a high-brightness x-ray source, and high-performance computing for analysis provide a revolutionary step forward in terms of imaging speed and resolution. We present x-ray microscopy with 8-nm full-period spatial resolution and use this capability in conjunction with operando sample environments and cryogenic imaging, which are now routinely available. Our multimodal approach will find wide use across many fields of science and facilitate correlative analysis of materials with other types of probes.

Nanopillar modified high-sensitivity asymmetric Graphene-GaN photodetector

Nanoscale ◽  
2021 ◽  
Author(s):  
Chang Liu ◽  
Xiaodong Li ◽  
Tiangui Hu ◽  
Wenkai Zhu ◽  
Faguang Yan ◽  
...  
Keyword(s):  
Electrical Properties ◽  
High Performance ◽  
2D Materials ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Optical And Electrical Properties ◽  
Two Dimensional

Integration of two dimensional (2D) materials with three dimensional (3D) semiconductors reveals intriguing optical and electrical properties that surpass those of the original materials. Here we report the high performance...

scholarly journals Development of Low-Cost Fast Photoacoustic Computed Tomography: System Characterization and Phantom Study

2019 ◽  
Vol 9 (3) ◽  
pp. 374 ◽  
Author(s):  
Mohsin Zafar ◽  
Karl Kratkiewicz ◽  
Rayyan Manwar ◽  
Mohammad Avanaki
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
High Performance ◽  
Low Cost ◽  
Single Element ◽  
Tomography System ◽  
System Characterization ◽  
2D Images ◽  
Fast Rotating

A low-cost Photoacoustic Computed Tomography (PACT) system consisting of 16 single-element transducers has been developed. Our design proposes a fast rotating mechanism of 360o rotation around the imaging target, generating comparable images to those produced by large-number-element (e.g., 512, 1024, etc.) ring-array PACT systems. The 2D images with a temporal resolution of 1.5 s and a spatial resolution of 240 µm were achieved. The performance of the proposed system was evaluated by imaging complex phantom. The purpose of the proposed development is to provide researchers a low-cost alternative 2D photoacoustic computed tomography system with comparable resolution to the current high performance expensive ring-array PACT systems.

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