A5053064070- Graphene research and applications
- 2D Materials and Applications
- Magnetic properties of thin films
- Topological Materials and Phenomena
- Carbon Nanotubes in Composites
- Rare-earth and actinide compounds
- Advanced Condensed Matter Physics
- Perovskite Materials and Applications
- Magnetic Properties of Alloys
- Molecular Junctions and Nanostructures
- Surface and Thin Film Phenomena
- Electrohydrodynamics and Fluid Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Advanced Memory and Neural Computing
- Semiconductor materials and devices
- Physics of Superconductivity and Magnetism
- Ion-surface interactions and analysis
- Heusler alloys: electronic and magnetic properties
- Magnetic Properties and Applications
- Iron-based superconductors research
- Multiferroics and related materials
- Quantum and electron transport phenomena
- Force Microscopy Techniques and Applications
- Nanopore and Nanochannel Transport Studies
- Advancements in Semiconductor Devices and Circuit Design
Korea Institute of Science and Technology
2014-2025
University of Maryland, College Park
2007-2010
Korea University
2009
National Cheng Kung University
2007-2008
Layered transition metal dichalcogenides (TMDs) draw much attention as the key semiconducting material for two-dimensional electrical, optoelectronic, and spintronic devices. For most of these applications, both n- p-type materials are needed to form junctions support bipolar carrier conduction. However, typically only one type doping is stable a particular TMD. example, molybdenum disulfide (MoS2) natively an n-type presumably due omnipresent electron-donating sulfur vacancies,...
Irradiation of graphene on ${\mathrm{SiO}}_{2}$ by 500 eV Ne and He ions creates defects that cause intervalley scattering as is evident from a significant Raman $D$ band intensity. The defect gives conductivity proportional to charge carrier density, with mobility decreasing the inverse ion dose. decrease 4 times larger than for similar concentration singly charged impurities. minimum decreases values lower $4{e}^{2}/\ensuremath{\pi}h$, theoretical value free scattering. Defected shows...
We reduce the dimensionless interaction strength alpha in graphene by adding a water overlayer ultrahigh vacuum, thereby increasing dielectric screening. The mobility limited long-range impurity scattering is increased over 30%, due to background constant enhancement leading reduced of electrons with charged impurities. However, carrier-density-independent conductivity short-range impurities decreased almost 40%, screening potential conduction electrons. minimum nearly unchanged, canceling...
Flexible and transparent electronic devices with extremely high mobilities are fabricated from a graphene sheet, single atomic layer of graphite, by using the transfer printing method. "Printed" circuits achieve field effect up to 10000 cm2/Vs at room temperature. Our technique is scaleable more chemically-gentle process for fabricating quality graphene, nanoscale in general.
Identifying material parameters affecting properties of ferromagnets is key to optimized materials that are better suited for spintronics. Magnetic anisotropy particular importance in van der Waals magnets, since it not only influences magnetic and spin transport properties, but also essential stabilizing order the two-dimensional limit. Here, we report hole doping effectively modulates a ferromagnet explore physical origin this effect. Fe3-xGeTe2 nanoflakes show significant suppression with...
Spin–torque nano–oscillators (STNOs) have outstanding advantages of a high degree compactness, high–frequency tunability and good compatibility with the standard complementary metal–oxide–semiconductor process, which offer prospects for future wireless communication. There as yet been no reports on communication using STNOs, since STNOs also notable disadvantages such lower output power poorer spectral purity in comparison those LC voltage–controlled oscillators. Here we show that is...
High-resolution noncontact atomic force microscopy of ${\mathrm{SiO}}_{2}$ reveals previously unresolved roughness at the few-nm length scale, and scanning tunneling graphene on shows to be slightly smoother than supporting substrate. A quantitative energetic analysis explains observed as extrinsic, a natural result highly conformal adhesion. Graphene conforms substrate down smallest features with nearly 99% fidelity, indicating adhesion can effective for strain engineering graphene.
Dzyaloshinskii-Moriya interaction (DMI), which arises from the broken inversion symmetry and spin-orbit coupling, is of prime interest as it leads to a stabilization chiral magnetic order provides an efficient manipulation nanostructures. Here, we report all-electrical measurement DMI using propagating spin wave spectroscopy based on collective with well-defined vector. We observe substantial frequency shift waves depending chirality in Pt/Co/MgO structures. After subtracting contribution...
van der Waals (vdW) magnetic materials provide an ideal platform to study low-dimensional magnetism. However, observations of characteristics these layered truly distinguishing them from conventional thin film systems have been mostly lacking. In effort investigate properties unique vdW materials, we examine the exchange bias effect, a phenomenon emerging at ferromagnetic-antiferromagnetic interface. Exchange is observed in naturally oxidized ferromagnet Fe3GeTe2, owing antiferromagnetic...
We investigate the voltage control of magnetism in a van der Waals (vdW) heterostructure device consisting two distinct vdW materials, ferromagnetic Fe3-xGeTe2 and ferroelectric In2Se3. It is observed that gate voltages applied to Fe3-xGeTe2/In2Se3 modulate magnetic properties with significant decrease coercive field for both positive negative voltages. Raman spectroscopy on shows voltage-dependent increase in-plane In2Se3 lattice constants polarities. Thus, field, regardless polarity, can...
Abstract The Berry curvature dipole (BCD) serves as a one of the fundamental contributors to emergence nonlinear Hall effect (NLHE). Despite intense interest due its potential for new technologies reaching beyond quantum efficiency limit, interplay between BCD and NLHE has been barely understood yet in absence systematic study on electronic band structure. Here, we report realized NbIrTe 4 that persists above room temperature coupled with sign change conductivity at 150 K. First-principles...
Halide perovskite (HP) composites with transition metal dichalcogenides (TMDs) have attracted attention as promising photocatalysts for hydrogen production through solar-driven water splitting but their working mechanism is yet unclear. Here, we propose novel heterostructures composed of all-inorganic HP β-CsPbI3 and metallic TMD 1T-MoS2 investigate the influence interfacial vacancies on properties using first-principles calculations. Using CsPbI3(001)/MoS2(001) interface slab models a...
Two-dimensional (2D) van der Waals semiconductors show promise for atomically thin, flexible, and transparent optoelectronic devices in future technologies. However, developing high-performance field-effect transistors (FETs) based on 2D materials is...
A hydrodynamic phenomenon is used to assemble a large-scale conductive nanomesh of single-walled carbon nanotubes (SWNTs) with exceptional control the nanostructure. This accomplished by biological material nanoscale features and strong binding affinity toward SWNTs. The also presents unique glue effect for assembly. Unprecedented characteristics are observed nanomesh. As service our authors readers, this journal provides supporting information supplied authors. Such materials peer reviewed...
We report on temperature-dependent charge and magneto transport of chemically doped MoS2, p-type molybdenum disulfide degenerately with niobium (MoS2:Nb). The temperature dependence the electrical resistivity is characterized by a power law, ρ(T) ∼ T−0.25, which indicates that system resides within critical regime metal-insulator (M-I) transition. By applying high magnetic field (∼7 T), we observed 20% increase in at 2 K. positive magnetoresistance shows this governed Mott-like...
Electric-field-induced modification of magnetic anisotropy is studied using tunnel magnetoresistance the Co40Fe40B20/ MgO/ Co40Fe40B20 and Hf (0.08 nm)/ junctions. In both systems, interfacial perpendicular increased with increasing electron density at MgO interface. A quantitative comparison between two systems reveals that change energy electric field significantly enhanced in Hf/ compared to Co40Fe40B20. The sub-monolayer insertion Co40Fe40B20/MgO interface turns out be critical control...
The Kondo insulator compound $\mathrm{Sm}{\mathrm{B}}_{6}$ has emerged as a strong candidate for the realization of topologically nontrivial state in strongly correlated system, topological insulator, which can be novel platform investigating interplay between topology and emergent correlation-driven phenomena solid-state systems. Electronic transport measurements on this material, however, so far showed only robust surface-dominated charge conduction at low temperatures, lacking evidence...
We present a post-growth ex-situ annealing method to control the Curie temperature and magnetic anisotropy of Cr2Te3 van der Waals ferromagnetic thin films. The as-grown films exhibit ∼ 170 K with an out-of-plane easy axis. Upon high (300–400 °C) annealing, phase film changes: is significantly increased 300 axis reoriented in-plane direction. Electronic, chemical, structural analyses suggest that c-axis lattice constant expansion, accompanying process, origin ex-situ-annealing-induced...
Abstract Room-temperature magnetism and its stability upon miniaturization are essential characteristics required for materials spintronic devices information storage. Among various candidates, Fe 3 GaTe 2 stands out due to high Curie temperature strong perpendicular magnetic anisotropy (PMA), recently gaining large attention as one of the promising candidate spintronics applications. In this study, we measured thickness-dependent ferromagnetic properties (Fe 1 − x Ni ) (with = 0.1) flakes....