A5062092411- Rare-earth and actinide compounds
- Iron-based superconductors research
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Nuclear Materials and Properties
- Magnetic Properties of Alloys
- Plasmonic and Surface Plasmon Research
- Inorganic Chemistry and Materials
- Photonic and Optical Devices
- Advancements in Semiconductor Devices and Circuit Design
- Magnetic and transport properties of perovskites and related materials
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Inorganic Fluorides and Related Compounds
- Superconductivity in MgB2 and Alloys
- Superconducting Materials and Applications
- Thermodynamic and Structural Properties of Metals and Alloys
- Crystallization and Solubility Studies
- Semiconductor Quantum Structures and Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Low-power high-performance VLSI design
- 3D IC and TSV technologies
- Gold and Silver Nanoparticles Synthesis and Applications
- Crystal Structures and Properties
- ZnO doping and properties
Fudan University
2015-2025
Commercial Aircraft Corporation of China (China)
2025
State Key Laboratory of Surface Physics
2015-2024
Taiwan Semiconductor Manufacturing Company (Taiwan)
2011-2024
Lawrence Livermore National Laboratory
2021-2023
University of California, San Diego
2011-2021
NARI Group (China)
2021
Florida State University
2017-2020
National High Magnetic Field Laboratory
2017-2020
Nankai University
2018
We report on violet-emitting III-nitride light-emitting diodes (LEDs) grown bulk GaN substrates employing a flip-chip architecture. Device performance is optimized for operation at high current density and temperature, by specific design consideration the epitaxial layers, extraction efficiency, electrical injection. The power conversion efficiency reaches peak value of 84% 85 °C remains density, owing to low current-induced droop series resistance.
Polycrystalline samples of F-substituted LnOBiS2 (Ln = La, Ce, Pr, Nd, Yb) compounds were synthesized by solid-state reaction. The characterized x-ray diffraction measurements and found to have the ZrCuSiAs crystal structure. Electrical resistivity magnetic susceptibility performed on all specific heat made those with Ln Yb. All these exhibit superconductivity in range 1.9 K - 5.4 K, which has not previously been reported for based YbO0.5F0.5BiS2 was also order at ~2.7 that apparently...
We report a strategy to induce superconductivity in the BiS$_2$-based compound LaOBiS$_2$. Instead of substituting F for O, we increase charge-carrier density (electron dope) via substitution tetravalent Th$^{+4}$, Hf$^{+4}$, Zr$^{+4}$, and Ti$^{+4}$ trivalent La$^{+3}$. It is found that both LaOBiS$_2$ ThOBiS$_2$ parent compounds are bad metals induced by electron doping with \emph{T$_c$} values up 2.85 K. The superconducting normal states were characterized electrical resistivity, magnetic...
This work presents a novel method to introduce sustainable biaxial tensile strain larger than 1% in thin Ge membrane using stressor layer integrated on Si substrate. Raman spectroscopy confirms 1.13% and photoluminescence shows direct band gap reduction of 100meV with enhanced light emission efficiency. Simulation results predict that combination 1.1% heavy n(+) doping reduces the required injected carrier density for population inversion by over factor 60. We also present first highly...
Heavy-fermion systems share some of the strange metal phenomenology seen in other unconventional superconductors, providing a unique opportunity to set metals broader context. Central understanding heavy-fermion is interplay localization and itinerancy. These materials acquire high electronic masses concomitant Fermi volume increase as $f$ electrons delocalize at low temperatures. However, despite wide-spread acceptance this view, direct microscopic verification has been lacking. Here we...
Electrical resistivity measurements as a function of temperature between 1 K and 300 were performed at various pressures up to 3 GPa on the superconducting layered compounds Ln(O0.5F0.5)BiS2 (Ln = La, Ce). At atmospheric pressure, La(O0.5F0.5)BiS2 Ce(O0.5F0.5)BiS2 have critical temperatures, Tc, 3.3 2.3 K, respectively. For both compounds, Tc initially increases, reaches maximum value 10.1 for 6.7 CeO(0.5F0.5)BiS2, then gradually decreases with increasing pressure. Both samples also exhibit...
We demonstrate room-temperature electroluminescence (EL) from light-emitting diodes (LED) on highly strained germanium (Ge) membranes. An external stressor technique was employed to introduce a 0.76% bi-axial tensile strain in the active region of vertical PN junction. Electrical measurements show an on-off ratio increase one order magnitude membrane LEDs compared bulk. The EL spectrum Ge LED shows 100nm redshift center wavelength because strain-induced direct band gap reduction. Finally,...
Measurements of electrical resistivity were performed between 3 and 300 K at various pressures up to 2.8 GPa on the BiS2-based superconductors LnO0.5F0.5BiS2 (Ln = Pr, Nd). At lower pressures, PrO0.5F0.5BiS2 NdO0.5F0.5BiS2 exhibit superconductivity with critical temperatures Tc 3.5 and3.9 K, respectively. As pressure is increased, both compounds undergo a transition Pt from low superconducting phase high in which reaches maximum values 7.6 6.4 for NdO0.5F0.5BiS2, The pressure-induced...
The authors report experimental confirmation of backscattering enhancement induced by a photonic jet emerging from dielectric sphere, phenomenon recently predicted theoretical solutions Maxwell’s equations. To permit relatively straightforward laboratory measurements at microwave frequencies rather than visible light, they appropriately scaled the original conceptual dimensions microsphere and its adjacent perturbing nanoparticle (located within microsphere’s jet). Their experiments verified...
New plasmonic materials with tunable properties are in great need for nanophotonics and metamaterials applications. Here we present two-dimensional layered, metal chalcogenides as that feature both dielectric photonic modes across a wide spectral range from the infrared to ultraviolet. The anisotropic layered structure allows intercalation of organic molecules atoms at van der Waals gap host chalcogenide, presenting chemical route create heterostructures molecular atomic precision This marks...
Over the past decade, properties of plasmonic waveguides have extensively been studied as key elements in important applications that include biosensors, optical communication systems, quantum plasmonics, logic, and quantum-cascade lasers. Whereas their guiding are by now fairly well-understood, practical implementation chipscale systems is hampered lack convenient electrical excitation schemes. Recently, a variety surface plasmon lasers realized, but they not yet waveguide-coupled. Planar...
Muon relaxation experiments reveal a slowly fluctuating magnetic field in the pseudogap phase of cuprate superconductor.
At the nanoscale, semiconductor and metallic structures naturally exhibit strong, tunable optical resonances that can be utilized to enhance light-matter interaction dramatically increase performance of chipscale photonic elements. Here, we demonstrate leads used extract current from a Ge nanowire (NW) photodetector redesigned serve as antennas capable concentrating light in NW. The NW itself also made optically resonant an overall optimization involves careful tuning both resonances. We...
In order to address the issue of APU rotator overspeed, which can lead a hazardous failure condition, it is necessary develop an Electronics Control Unit (ECU) with Design Assurance Level (DAL) B. The development such unit essential for mitigating this risk. However, should be noted that cost and time required developing DAL B software or hardware are much higher compared non-DAL required. Therefore, paper aims propose method designing overspeed protection circuit using Simple Hardware (SEH)...
Lithium-ion battery cathode material Li3.2x(V1.xTix)2(PO4)3 was synthesized using sol-gel/carbothermal reduction method. Electrochemical properties of substituted samples were investigated, which showed the enhancement discharge capacity and cycle performance by substitution Ti4+. The pure Li3V2(PO4)3 presented three plateaus around 3.58, 3.67, 4.08 V, but first two slightly sloping in boundary gradually became ambiguous with increase ratio. differential thermal analysis (DTA) indicated that...
We report on the light extraction efficiency of III-Nitride violet light-emitting diodes with a volumetric flip-chip architecture. introduce an accurate optical model to account for extraction. fabricate series devices varying configurations and fit their measured performance our model. show importance second-order effects like photon recycling residual surface roughness data. conclude that reach 89%.
We have used high-resolution neutron spectroscopy experiments to determine the complete spin wave spectrum of heavy fermion antiferromagnet CeRhIn$_5$. The dispersion can be quantitatively reproduced with a simple $J_1$-$J_2$ model that also naturally explains magnetic spin-spiral ground state CeRhIn$_5$ and yields dominant in-plane nearest-neighbor exchange constant $J_0$ = 0.74 meV. Our results pave way quantitative understanding rich low-temperature phase diagram prominent Ce$T$In$_5$...
We experimentally investigate the symmetry in Hidden Order (HO) phase of intermetallic URu2Si2 by mapping lattice and magnetic excitations via inelastic neutron x-ray scattering measurements HO high-temperature paramagnetic phases. At all temperatures respect zone edges body-centered tetragonal phase, showing no signs reduced spatial symmetry, even phase. The originate from transitions between hybridized bands track Fermi surface, whose feature are corroborated phonon measurements. Due to a...
We have used specific heat and neutron diffraction measurements on single crystals of ${\mathrm{URu}}_{2\ensuremath{-}x}{\mathrm{Fe}}_{x}{\mathrm{Si}}_{2}$ for Fe concentrations $x\ensuremath{\le}0.7$ to establish that chemical substitution Ru with acts as ``chemical pressure'' ${P}_{ch}$ previously proposed by Kanchanavatee et al. [Phys. Rev. B 84, 245122 (2011)] based bulk polycrystalline samples. Notably, reveals a sharp increase the uranium magnetic moment at $x=0.1$, reminiscent...