A5057939435- 2D Materials and Applications
- Graphene research and applications
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- MXene and MAX Phase Materials
- Surface and Thin Film Phenomena
- ZnO doping and properties
- Advanced Electron Microscopy Techniques and Applications
- Force Microscopy Techniques and Applications
- Advanced Memory and Neural Computing
- Nanopore and Nanochannel Transport Studies
- Molecular Junctions and Nanostructures
- Superconducting and THz Device Technology
- Anodic Oxide Films and Nanostructures
- Electrochemical Analysis and Applications
- Superconductivity in MgB2 and Alloys
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- nanoparticles nucleation surface interactions
- Quantum Dots Synthesis And Properties
- GaN-based semiconductor devices and materials
- Graphene and Nanomaterials Applications
- Dielectric materials and actuators
- Physics of Superconductivity and Magnetism
Massachusetts Institute of Technology
2020-2024
IIT@MIT
2023
IBM Research - Thomas J. Watson Research Center
2020
University of Cambridge
2020
Harvard University
2020
Technical University of Denmark
2020
Brookhaven National Laboratory
2020
Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but remnant polarization has hindered effective deployment in energy storage applications. Previous methodologies have encountered problems because the deteriorated crystallinity ferroelectric materials. We introduce an approach control relaxation time using...
Abstract The atomic structure at the interface between two-dimensional (2D) and three-dimensional (3D) materials influences properties such as contact resistance, photo-response, high-frequency electrical performance. Moiré engineering is yet to be utilized for tailoring this 2D/3D interface, despite its success in enabling correlated physics 2D/2D interfaces. Using epitaxially aligned MoS 2 /Au{111} a model system, we demonstrate use of advanced scanning transmission electron microscopy...
Understanding the stability limitations and defect formation mechanisms in 2D magnets is essential for their utilization spintronic memory technologies. Here, we correlate defects mono- to multilayer CrSBr with structural, vibrational magnetic properties. We use resonant Raman scattering reveal distinct signatures. In pristine CrSBr, show that bromine atoms mediate interlayer coupling, allowing distinguishing between surface bulk modes. environmental exposure causes drastic degradation...
Abstract Ultra-fast single-photon detectors with high current density and operating temperature can benefit space ground applications, including quantum optical communication systems, lightweight cryogenics for crafts, medical use. Here we demonstrate magnesium diboride (MgB 2 ) thin-film superconducting microwires capable of detection at 1.55 μ m wavelength. We used helium ions to alter the properties MgB , resulting in microwire-based exhibiting sensitivity across a broad range up 20 K,...
Understanding structure at the interface between two-dimensional (2D) materials and 3D metals is crucial for designing novel 2D/3D heterostructures improving performance of many 2D material devices. Here, we quantify discuss morphology in several systems. We first deposit facetted Au nanoislands on graphene transition metal dichalcogenides, using measurements equilibrium island shape to determine values 2D/Au energies examining role surface reconstructions, chemical identity, defects grown...
Oxidation of transition metal dichalcogenides (TMDs) occurs readily under a variety conditions. Therefore, understanding the oxidation processes is necessary for successful TMD handling and device fabrication. Here, we investigate atomic-scale mechanisms most widely studied TMD, MoS2. We find that thermal results in α-phase crystalline MoO3 with sharp interfaces, voids, crystallographic alignment underlying Experiments remote substrates prove proceeds via vapor-phase mass transport...
Extraordinary optoelectronic properties of van der Waals (vdW) heterostructures can be tuned via strain caused by mechanical deformation. Here, we demonstrate strong and localized luminescence in the ultraviolet region from interface bubbles between stacked multilayers hexagonal boron nitride (hBN). Compared to monolayers, formed stacking vdW show distinct behavior. We use this behavior elucidate radius- thickness-dependent bubble geometry resulting across bubble, which establish bending...
Abstract The method of salt‐assisted vapor–liquid–solid (VLS) growth is introduced to synthesize 1D nanostructures trichalcogenide van der Waals (vdW) materials, exemplified by niobium trisulfide (NbS 3 ). uses a unique catalyst consisting an alloy Au and alkali metal halide (NaCl) enable rapid directional growth. High yields two types NbS nanostructures, nanowires nanoribbons, each with sub‐ten nanometer diameter, tens micrometers length, distinct morphology orientation are demonstrated....
The integration of metallic contacts with two-dimensional (2D) semiconductors is routinely required for the fabrication nanoscale devices. However, nanometer-scale variations in 2D/metal interface can drastically alter local optoelectronic properties. Here, we map excitonic changes 2D semiconductor MoS2 contact Au. We utilize a suspended and epitaxially grown platform that allows correlated electron energy-loss spectroscopy (EELS) angle resolved photoelectron (nanoARPES) mapping. Spatial...
Abstract The combination of imaging with electrochemical quantification in liquid cell transmission electron microscopy (TEM) provides opportunities for visualizing material processes good spatial and temporal resolution a way that is inaccessible bench‐top experiments. electrode used TEM determines the reliability consistency measurements also influences when on electrode. Here, arising from use 2D materials electrochemistry are explored. Through modeling, it demonstrated graphene...
The combination of electrochemical analysis, temperature control and <italic>in situ</italic> TEM imaging directly probes the etching Ni from bimetallic Ni–Pt nanoparticles.
The formation of well-controlled interfaces between materials different structure and bonding is a key requirement when developing new devices functionalities. Of particular importance are epitaxial or low defect density two-dimensional three-dimensional semiconductors metals, where an interfacial influences electrical conductivity in field effect optoelectronic devices, charge transfer for spintronics catalysis, proximity-induced superconductivity. Epitaxy hence well-defined has been...
Control of nucleation sites is an important goal in materials growth: nuclei regular arrays may show emergent photonic or electronic behavior, and once the coalesce into thin films, density influences parameters such as surface roughness, stress, grain boundary structure. Tailoring substrate properties to control therefore a powerful tool for designing functional films nanomaterials. Here, we examine metals deposited on two-dimensional (2D) situation where effects are absent heterogeneous...
Abstract The synthesis of large‐area TiS 2 thin films is reported at temperatures as low 500 °C using a scalable two‐step method metal film deposition followed by sulfurization in an H S gas furnace. It demonstrated that the lowest‐achievable temperature depends strongly on oxygen background during sulfurization. This dependence arises because TiO bonds present substantial kinetic and thermodynamic barrier to formation. Lowering important make smooth films, enable integration related...
We report the synthesis of large-area, high-Ti-content, Mo1−xTixS2 alloy thin films in 2H phase at temperature as low 500 °C using a scalable two-step method metal film deposition, followed by sulfurization H2S. Film processing higher accelerates Ti segregation, coarsening, and formation TiS2 1T phase. Crystal growth results multiple binary sulfide phases, agreement with equilibrium diagram. Making highly metastable, smooth, uniform single-phase films, therefore, hinges on developing...
Ultra-fast single-photon detectors with high current density and operating temperature can benefit space ground applications, including quantum optical communication systems, lightweight cryogenics for crafts, medical use. Here we demonstrate magnesium diboride (MgB$_2$) thin-film superconducting microwires capable of detection at 1.55 $\mu$m wavelength. We used helium ions to alter the properties MgB$_2$, resulting in microwire-based exhibiting sensitivity across a broad range up 20 K,...
Titanium (Ti) is an adhesion and contact metal commonly used in nanoelectronics two-dimensional (2D) materials research. However, when Ti deposited on graphene (Gr), we obtain dramatically different film morphology depending the experimental conditions. Through a combination of transmission electron microscopy, Raman spectroscopy, ab initio density functional theory calculations, show that most critical parameters are number Gr layers, nature support, deposition temperature. Particularly...
Beyond graphene, many two-dimensional materials (2DMs) have now been isolated with an exciting range of properties: insulators, semiconductors, metals, semimetals, superconductors, topological piezoresistors, and ferromagnets.More than 1800 these 2DMs predicted to exist [1].However, the full potential this diverse set can only be fully exploited if interfaced in a well-controlled fashion common 3DMs used technology, such as metals or either nanoscale crystals larger area contacts.The...
We have combined the benefits of two catalytic growth phenomena to form nanostructures transition metal trichalcogenides (TMTs), materials that are challenging grow in a nanostructured by conventional techniques, as required exploit their exotic physics. Our strategy combines vapor-liquid-solid (VLS) controlling dimension and location, salt-assisted for fast at moderate temperatures. This VLS is enabled through use catalyst includes Au an alkali halide. demonstrate high yields NbS3 1D with...
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