A5085076976- 2D Materials and Applications
- Graphene research and applications
- MXene and MAX Phase Materials
- Perovskite Materials and Applications
- Nanowire Synthesis and Applications
- Advanced Electron Microscopy Techniques and Applications
- SARS-CoV-2 and COVID-19 Research
- Advanced Thermoelectric Materials and Devices
- Virus-based gene therapy research
- Molecular Junctions and Nanostructures
- Ga2O3 and related materials
- Photosynthetic Processes and Mechanisms
- Chalcogenide Semiconductor Thin Films
- COVID-19 diagnosis using AI
- Enzyme Structure and Function
- Thermal properties of materials
- Advanced Sensor and Energy Harvesting Materials
- Animal Virus Infections Studies
- RNA and protein synthesis mechanisms
- Quantum Dots Synthesis And Properties
- Quantum and electron transport phenomena
- Carbon Nanotubes in Composites
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Viral Infections and Outbreaks Research
Diamond Light Source
2020-2025
Nanjing University of Posts and Telecommunications
2025
University of Oxford
2015-2021
Research Complex at Harwell
2021
Centro Laser
2021
Central Laser Facility
2021
University of Pittsburgh
2021
University of Cambridge
2021
Appleton Public Library
2021
Since the outbreak of SARS-CoV-2 pandemic, there have been intense structural studies on purified viral components and inactivated viruses. However, ultrastructural evidence how infection progresses in native cellular context is scarce, a lack comprehensive knowledge replicative cycle. To correlate cytopathic events induced by with virus replication processes frozen-hydrated cells, we established unique multi-modal, multi-scale cryo-correlative platform to image Vero cells. This combines...
Abstract A demonstration is presented of how significant improvements in all‐2D photodetectors can be achieved by exploiting the type‐II band alignment vertically stacked WS 2 /MoS semiconducting heterobilayers and finite density states graphene electrodes. The photoresponsivity heterobilayer devices increased more than an order magnitude compared to homobilayer two orders monolayer MoS , reaching 10 3 W −1 under illumination power 1.7 × mW cm −2 . massive improvement performance due strong...
Understanding the stability of monolayer transition metal dichalcogenides in atmospheric conditions has important consequences for their handling, life-span, and utilization applications. We show that cryogenic photoluminescence spectroscopy (PL) is a highly sensitive technique to detection oxidation induced degradation tungsten disulfide (WS2) caused by exposure ambient conditions. Although long-term causes massive from optically visible, short-term produces no obvious changes PL or Raman...
We show that reducing the degree of van der Waals overlapping in all 2D ultrathin lateral devices composed graphene:WS2:graphene leads to significant increase photodetector responsivity. This is achieved by directly growing WS2 using chemical vapor deposition (CVD) prepatterned graphene gaps create epitaxial interfaces. Direct-CVD-grown photodetecting transistors exhibit high photoresponsivities reaching 121 A/W under 2.7 × 105 mW/cm2 532 nm illumination, which around 2 orders magnitude...
A chemical vapor deposition method is developed for thickness-controlled (one to four layers), uniform, and continuous films of both defective gallium(II) sulfide (GaS): GaS0.87 stoichiometric GaS. The unique degradation mechanism with X-ray photoelectron spectroscopy annular dark-field scanning transmission electron microscopy studied, it found that the poor stability weak optical signal from GaS are strongly related photo-induced oxidation at defects. An enhanced demonstrated under laser...
We show how an oxide passivating layer on the Cu surface before growth of h-BN by chemical vapor deposition (CVD) can lead to increased domain sizes from 1 20 μm reducing nucleation density 106 103 mm–2. The domains within each grain are well-oriented, indicating epitaxial relationship between crystals and substrates that leads larger crystal film ∼100 μm. Continuous films grown a high degree monolayer uniformity. This CVD approach removes need for low pressures, electrochemical polishing,...
The solid progress in the study of a single two-dimensional (2D) material underpins development for creating 2D assemblies with various electronic and optoelectronic properties. We introduce an asymmetric structure by stacking monolayer semiconducting tungsten disulfide, metallic graphene, insulating boron nitride to fabricate numerous red channel light-emitting devices (LEDs). All crystals were grown chemical vapor deposition (CVD), which has great potential future industrial scale-up. Our...
Monolayer transition metal dichalcogenides (TMDs) are direct band gap semiconductors, and their 2D structure results in large binding energies for excitons, trions, biexcitons. The ability to explore many-body effects these monolayered structures has made them appealing future optoelectronic photonic applications. changes bilayer TMDs with increased contributions from indirect transitions, this limited similar in-depth studies of Here, we study biexciton emission WS2 grown by chemical vapor...
Although it was demonstrated that discrete molecular levels determine the sign and magnitude of thermoelectric effect in single-molecule junctions, full electrostatic control these has not been achieved to date. Here, we show graphene nanogaps combined with gold microheaters serve as a testbed for studying thermoelectricity. Reduced screening gate electric field compared conventional metal electrodes allows position dominant transport orbital by hundreds meV. We find power factor...
The 2D semiconductor monolayer transition metal dichalcogenides, WS2 and MoS2 , are grown by chemical vapor deposition (CVD) assembled sequential transfer into vertical layered heterostructures (VLHs). Insulating hBN, also produced CVD, is utilized to control the separation between adjusting layer number, leading fine-scale tuning of interlayer interactions within VLHs. studied photoluminescence (PL) spectroscopy demonstrated be highly sensitive input excitation power. For thin hBN...
The influence of nanostructuring and quantum confinement on the thermoelectric properties materials has been extensively studied. While this made possible multiple breakthroughs in achievable figure merit, classical confinement, its effect local Seebeck coefficient mostly neglected, as Peltier general due to complexity measuring small temperature gradients locally. Here we report that reducing width a graphene channel 100 nm changes by orders magnitude. Using scanning thermal microscope...
Two dimensional (2D) materials have found various applications because of their unique physical properties. For example, graphene has been used as the electron transparent membrane for liquid cell transmission microscopy (TEM) due to its high mechanical strength and flexibility, single-atom thickness, chemical inertness, etc. Here, we report using 2D MoS2 a functional substrate well window TEM, which is enabled by our facile polymer-free transfer process. This provides opportunity...
Methane-oxidizing bacteria play a central role in greenhouse gas mitigation and have potential applications biomanufacturing. Their primary metabolic enzyme, particulate methane monooxygenase (pMMO), is housed copper-induced intracytoplasmic membranes (ICMs), of which the function biogenesis are not known. We show by serial cryo-focused ion beam (cryoFIB) milling/scanning electron microscope (SEM) volume imaging lamellae-based cellular cryo-electron tomography (cryoET) that these ICMs...
We show that hexagonal domains of monolayer tungsten disulfide (WS2) grown by chemical vapor deposition (CVD) with powder precursors can have discrete segmentation in their photoluminescence (PL) emission intensity, forming symmetric patterns alternating bright and dark regions. Two-dimensional maps the PL reveal significant reduction within segments associated longest sides domains. Analysis spectra shows differences exciton to trion ratio, indicating variations recombination dynamics....
Graphene provides a two-dimensional platform for contacting individual molecules, which enables transport spectroscopy of molecular orbital, spin, and vibrational states. Here we report single-electron tunneling through molecule that has been anchored to two graphene leads. Quantum interference within the leads gives rise an energy-dependent transmission fluctuations in sequential tunnel-rates. The lead states are electrostatically tuned by global back-gate, resulting distinct pattern...
Large single-crystal domains of WS2 are grown by chemical vapor deposition, and their photoluminescent properties under a lateral electric field studied. We demonstrate that monolayer bilayer have opposite responses to fields, with photoluminescence (PL) substantially reduced in increased bilayers increasing strength. Temperature-dependent PL measurements also undertaken show behavior distinctly different than the effects, ruling out heating as cause changes. The variation both is attributed...
Heterophase homojunction formation in atomically thin 2D layers is of great importance for next-generation nanoelectronics and optoelectronics applications. Technologically challenging, controllable transformation between the semiconducting metallic phases transition metal chalcogenides particular importance. Here, we demonstrate that controlled laser irradiation can be used to directly ablate PdSe2 films using high power or trigger local into a phase PdSe2-x lower power. Such...
Monolayer tungsten disulfide (WS2) offers great prospects for use in optoelectronic devices due to its direct bandgap and high photoluminescence intensity. Here, we show how the controlled addition of hydrogen into chemical vapor deposition growth WS2 can lead formation centimeter scale continuous monolayer films at ambient pressure without need seed molecules, specially prepared substrates, or low vacuum systems. Modifications reaction conditions, including time argon ratio, allow control...
We show how control over the chemical vapor deposition (CVD) reaction chemistry of molybdenum disulfide (MoS2) by hydrogen addition can enable direct growth centimeter-scale continuous films vertically stacked MoS2 monolayer on graphene under atmospheric pressure conditions. Hydrogen enables longer CVD times at high temperature reducing oxidation effects that would otherwise degrade graphene. By careful nucleation density and time, high-quality could be formed graphene, realizing all...
Abstract Lead Iodide (PbI 2 ) is a large bandgap 2D layered material that has potential for semiconductor applications. However, atomic level study of PbI monolayer been limited due to challenges in obtaining thin crystals. Here, we use liquid exfoliation produce nanodisks (30-40 nm diameter and > 99% purity) deposit them onto suspended graphene supports enable structure . Strong epitaxial alignment monolayers with the underlying lattice occurs, leading phase shift from 1 T H increase...
We explore the use of stable, pre-formed, oligomeric aminoboranes as precursors for chemical vapour deposition growth few-layered hexagonal boron nitride (h-BN) films on Cu foils under atmospheric pressure conditions. Dimeric diborazane H3B·NH2BH2·NH3 (DAB), and trimeric triborazane H3B·(NH2BH2)2·NH3 (TAB), derivatives ammonia borane, H3B·NH3 (AB), are compared with AB, a commonly used precursor CVD h-BN. Both DAB TAB show similar effectiveness to AB in growing h-BN few layered films. Using...
UV-sensitive lateral all-two-dimensional (2D) photodetecting devices are produced by growing the large band gap layered GaS between graphene electrode pairs directly using chemical vapor deposition methods. The use of prepatterned on Si wafer enables more than 200 to be fabricated simultaneously. We show that surface chemistry substrate during leads selective growth in gaps, forming heterostructures, rather graphene. graphene/GaS/graphene demonstrated sensitive UV light only, with no...
Here we study the layer-dependent photoconductivity in Gr/WS2/Gr vertical stacked tunneling (VST) cross-bar devices made using two-dimensional (2D) materials all grown by chemical vapor deposition. The larger number of (>100) enables a statistically robust analysis on comparative differences photovoltaic response monolayer and bilayer WS2, which cannot be achieved small batch mechanically exfoliated materials. We show dramatic increase for Gr/WS2(2L)/Gr compared to monolayers because long...
Two-dimensional gallium sulfide (GaS) crystals are synthesized by a simple and efficient ambient pressure chemical vapor deposition (CVD) method using single-source precursor of Ga2S3. The GaS structures involve triangular monolayer domains multilayer flakes with thickness 1 15 nm, respectively. Regions continuous films also achieved about 0.7 cm2 uniform coverage. This is hydrogen carrier gas the horizontally placed SiO2/Si substrates. Electron microscopy spectroscopic measurements used to...