A5080201843- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Phase-change materials and chalcogenides
- Ferroelectric and Piezoelectric Materials
- Silicon Nanostructures and Photoluminescence
- Luminescence Properties of Advanced Materials
- Photonic and Optical Devices
- Plasmonic and Surface Plasmon Research
- Metamaterials and Metasurfaces Applications
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Acoustic Wave Resonator Technologies
- Multiferroics and related materials
- Photorefractive and Nonlinear Optics
- Solid-state spectroscopy and crystallography
- Glass properties and applications
- Molecular Junctions and Nanostructures
- Magnetic and transport properties of perovskites and related materials
- Semiconductor Lasers and Optical Devices
- Copper-based nanomaterials and applications
- ZnO doping and properties
- Advanced Fiber Laser Technologies
- High-pressure geophysics and materials
- Perovskite Materials and Applications
- Crystal Structures and Properties
MIT Lincoln Laboratory
2024-2025
Massachusetts Institute of Technology
2024-2025
Physical Sciences (United States)
2017
Harvard University
2015-2017
University of California, Berkeley
2011-2013
Lawrence Berkeley National Laboratory
2011-2012
Material Sciences (United States)
2012
Cornell University
2005-2006
Columbia University
2005
Queens College, CUNY
2005
Nanocrystals of the wide band gap semiconductor zinc oxide controllable morphologies were synthesized by a simple thermal decomposition method. The predominating factor in determining morphology (spheres, triangular prisms, and rods) was solvent, selected on basis coordinating power. nanoparticles structurally analyzed, photoluminescence each shape compared. intensity green emission, common to many ZnO structures, found vary with morphology. strongest corresponded largest surface/volume...
The question of the nature and stability polar ordering in nanoscale ferroelectrics is examined with colloidal nanocrystals germanium telluride (GeTe). We provide atomic-scale evidence for room-temperature individual using aberration-corrected transmission electron microscopy demonstrate a reversible, size-dependent polar-nonpolar phase transition displacive character nanocrystal ensembles. A substantial linear component distortion observed, which contrast theoretical reports predicting...
Pure crystals: Ion exchange of semiconductor nanocrystals yielded materials with poor optoelectronic properties such as low photoluminescence quantum yields. The reason for the yields these are impurities at level a few atoms per nanocrystal. Cation-exchanged nanostructures, however, could be purified post from resulting in high-quality (see picture). Detailed facts importance to specialist readers published ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or...
Germanium telluride (GeTe) exhibits interesting materials properties, including a reversible amorphous-to-crystalline phase transition and room-temperature ferroelectric distortion, has demonstrated potential for nonvolatile memory applications. Here, colloidal approach to the synthesis of GeTe nanocrystals over wide range sizes is demonstrated. These have size distributions 10-20% exist in rhombohedral structure characteristic low-temperature polar phase. The production widely varying...
Infrared absorption measurements of amorphous and crystalline nanoparticles GeTe reveal a localized surface plasmon resonance (LSPR) mode in the phase that is absent phase. The LSPR emerges upon crystallization nanoparticles. contrasting plasmonic properties are elucidated with scanning tunneling spectroscopy indicating Burstein-Moss shift band gap finite density electronic states throughout limits effective free carrier density.
Light sources and photodetectors operating in the far- to midinfrared (FIR/MIR) band (8--12 \textmu{}m, 0.15--0.1 eV) remain relatively poorly developed compared their counterparts visible near-infrared ranges, despite extensive application potential for thermal imaging, standoff sensing, other technologies. This is attributable part lack of narrow-gap materials (0.1 with high optical gain absorption. In this work, a semiconductor, ${\mathrm{Pb}}_{0.7}{\mathrm{Sn}}_{0.3}\mathrm{Se}$,...
Defect-based color centers in wide-bandgap crystalline solids are actively being explored for quantum information science, sensing, and imaging. Unfortunately, the luminescent properties of these emitters frequently degraded by blinking photobleaching that arise from poorly passivated host crystal surfaces. Here, a new method stabilizing photoluminescence charge state based on epitaxial growth an inorganic passivation layer is presented. Specifically, carbon antisite-vacancy pairs (CAV...
Tunable optical materials can enable more functionality while maintaining flexibility in a single aperture, which is relevant to making visible and infrared image sensing context aware. DARPA's Accelerating discovery of Optical Materials (ATOM) program exploring fundamental insights into the physics tunable with goal developing new for optic photonic applications. The specific characteristics interest are large change refractive index (Δn) delay light, low loss high transmissivity (k), fast...
Perovskite oxides exhibit rich structural complexity and a broad range of functional properties, including ferroelectricity, ferromagnetism, superconductivity. The development aberration correction for the transmission electron microscope concurrent progress in spectroscopy, holography, other techniques has fueled rapid understanding physics chemistry these materials. New based on are first surveyed, applications study structure, chemistry, electrostatics, dynamics perovskite then explored...
High quality epitaxial (SrTiO3∕NiO)n∕MgO thin film multiferroic heterostructures have been fabricated using reactive off-axis sputtering. Crystal is verified x-ray diffraction and ion channeling. These comprise of dielectric antiferromagnetic layers that exhibit resonance resonance, respectively, at terahertz frequencies. In order to achieve epitaxy despite the large lattice mismatch between SrTiO3 NiO or MgO, high processing temperature required. The has led a small amount interdiffusion...
We show experimentally that structural defects in metal thiophosphate AgScP 2 S 6 are prominent exhibiting photoluminescence, which is likely driven by the defect-state-to-bulk-band transitions and can be further tuned temperature-induced strain gradients.
Low‐resistance Ohmic contacts are necessary for high‐performance electronic devices. Ultrawide‐bandgap semiconductor materials typically have high‐resistance between the metal contact and semiconductor. For single‐crystal boron‐doped diamond, with a bandgap of 5.5 eV, reported specific resistance values vary from >10 −3 Ω cm 2 to lowest value × 10 −7 . To obtain this low‐resistance contact, high temperature, >500 °C, annealing is usually required, which can limit fabrication procedures...
A 50 mW 325 nm He:Cd laser was used to irradiate the fracture surface of a commercial alkaline‐earth boroaluminosilicate display glass (Corning Code 1737) held at temperatures above 800 K. After this treatment, found be conductive for several hours in temperature range between room and 850 The conductivity shows an activation energy 0.18 eV. Scanning tunneling spectroscopy measurements indicate that is semiconducting with bandgap ∼4.4 It possible form topographical images using electron...
Die Autoren dieser Zuschrift möchten darauf hinweisen, dass im oberen Teil von Abbildung 1 B die x-Achsen Diagramm und Einschub um 80 nm verschoben wiedergegeben wurden: x-Achse des Diagramms muss 420 bis 670 reichen nicht 500 750 nm. mit den korrekten sind hier gezeigt. Alle weiteren Resultate Schlussfolgerungen Beitrags diesem Versehen betroffen. […︁] B) Photoluminescence spectra of CdS nanorods (top), obtained from hot injection (red), cation exchange (green), and post-change purification...