A5009110706- Plasmonic and Surface Plasmon Research
- ZnO doping and properties
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Thermal properties of materials
- Multiferroics and related materials
- Metamaterials and Metasurfaces Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Thermal Radiation and Cooling Technologies
- Optical Coatings and Gratings
- Advanced Thermoelectric Materials and Devices
- Copper-based nanomaterials and applications
- Nanowire Synthesis and Applications
- Magnetic Properties and Synthesis of Ferrites
- Neural Networks and Reservoir Computing
- Magnetic properties of thin films
- Ga2O3 and related materials
- Optical Polarization and Ellipsometry
- Advanced materials and composites
- Machine Learning in Materials Science
- Semiconductor Quantum Structures and Devices
- Transition Metal Oxide Nanomaterials
- Advanced Memory and Neural Computing
- Advanced Semiconductor Detectors and Materials
Third Way
2020-2021
North Carolina State University
2012-2019
TU Wien
2011
Abstract Configurational disorder can be compositionally engineered into mixed oxide by populating a single sublattice with many distinct cations. The formulations promote novel and entropy-stabilized forms of crystalline matter where metal cations are incorporated in new ways. Here, through rigorous experiments, simple thermodynamic model, five-component formulation, we demonstrate beyond reasonable doubt that entropy predominates the landscape, drives reversible solid-state transformation...
This work introduces oxidative molecular layer deposition (oMLD) as a chemical route to synthesize highly conductive and conformal poly(3,4-ethylenedioxythiophene) (PEDOT) thin films via sequential vapor exposures of molybdenum(V) chloride (MoCl5, oxidant) ethylene dioxythiophene (EDOT, monomer) precursors. The growth temperature strongly affects PEDOT's crystalline structure electronic conductivity. Films deposited at ∼150 °C exhibit textured structure, with {010} planes aligned parallel...
In this report we demonstrate fluorine-doped CdO as a model infrared plasmonic material by virtue of its tunable carrier density, high mobility, and intense extreme-subwavelength plasmon–polariton coupling. Carrier concentrations ranging from 1019 to 1020 cm–3, with electron mobility values 473 cm2/V·s, are readily achieved in epitaxial films over thickness range spanning 50 500 nm. concentration is reactive sputtering an Ar/O2 atmosphere trace quantities CF4. Infrared reflectometry...
Surface plasmon resonance (SPR) in semiconducting materials at mid-infrared (mid-IR) energies offers the potential for new plasmonic functionalities and integration schemes. Mainstream semiconductors are transparent to mid-IR energies, thus a tightly integrated monolithic package SPR sensing becomes feasible. We report surface zinc oxide as model material with 4 × 1019 8 cm−3 carriers. The modes were characterized using spectroscopic IR-ellipsometry compared reflectivity simulation. data...
We present experimental measurements of the thermal boundary conductance (TBC) from 78–500 K across isolated heteroepitaxially grown ZnO films on GaN substrates. This data provides an assessment underlying assumptions driving phonon gas-based models, such as diffuse mismatch model (DMM), and atomistic Green's function (AGF) formalisms used to predict TBC. Our measurements, when compared previous data, suggest that TBC can be influenced by long wavelength, zone center modes in a material one...
Review of material properties conducting metal oxides that make them suitable for mid-infrared surface plasmon resonance applications.
Donor doped CdO thin films on c-plane sapphire are prepared by reactive co-sputtering from Cd-metal and Y-metal targets which driven using pulsed-dc RF power respectively. Intrinsic exhibits a carrier density of 1.8 × 1019 cm−3 mobility 330 cm2 V−1 s−1. By increasing the Y-flux, values can be increased smoothly reproducibly to maximum value 3.3 1020 cm−3. Mobility increases with Y flux, broad plateau between approximately 5 2 Higher concentrations produce sharp drop in mobility. The increase...
In this Letter, we demonstrate a new class of infrared nanophotonic materials based on monolithic, multilayered doped cadmium oxide (CdO) thin films, where each CdO layer is individually tuned to support separate epsilon-near-zero (ENZ) resonance. Infrared reflectivity measurements reveal that the optical response stack combines multiple discrete absorption events, associated with an individual ENZ plasmonic polaritonic mode. Structural and chemical characterization confirm multilayers are...
Controllable Ge doping in GaN is demonstrated for carrier concentrations of up to 2.4 × 1020 cm−3. Low temperature luminescence spectra from the highly doped samples reveal band gap renormalization and filling (Burstein-Moss shift) addition a sharp transition. Infrared ellipsometry demonstrate existence electron plasma with an energy around 3500 cm−1 surface 2000 cm−1. These findings open possibilities application plasmonic devices.
For many industrial and manufacturing applications, detecting identifying low concentrations of harmful gases byproducts are performed using nondispersive infrared (NDIR) sensors. These simple devices utilize a broadband IR emitter, thermopile detector, spectrally narrow bandpass filter tuned to vibrational resonance the analyte interest. However, such filters expensive fabricate limit NDIR operation at only single frequency, unless wheels employed, which expand size complexity device...
Understanding the impact and complex interaction of thermal carrier scattering centers in functional oxide systems is critical to their progress application. In this work, we study interplay among electron phonon transport, mass-impurity scattering, phonon-vacancy interactions on conductivity cadmium oxide. We use time domain thermoreflectance measure a set CdO thin films doped with Dy up saturation limit. Using measurements at room temperature 80 K, our results suggest that enhancement low...
Indium tin oxide (ITO) has been the most widely studied conducting metal and serves as best candidate for proof-of-concept experiments in field of surface plasmon resonance studies electric confinement manipulation. ITO is chemically stable relatively easy to sputter. In this report, arrays nanostructures were produced using nanosphere lithography, which was originally developed plasmonic applications involving noble metals. However, presented here show that patterned with similar size shape...
Polycrystalline NiFe2O4 (NFO) thin films are grown on (111) platinized Si substrates via chemical solution processing. θ-2θ x-ray diffraction, pole figures and electron diffraction indicate that the NFO has a high degree of 〈111〉 uniaxial texture normal to film plane. The texturing is initiated by nucleation planes at Pt interface enhanced with decreasing thickness. As magnetic easy-axis 〈111〉, out-of-plane magnetization exhibits improved Mr/Ms coercivity respect randomly oriented silicon...
Chemical solution deposition is used to grow biaxially textured NiFe2O4 (NFO) thin films on (0001) sapphire substrates; a high degree of out-of-plane orientation in the 〈111〉 direction confirmed by θ–2θ X-ray diffraction and pole figures. φ-scanning indicates in-plane texture an epitaxial relationship between NFO (111) Al2O3 two crystallographic variants. The magnetization exhibits improved Mr/Ms from 0.5 110 nm-thick 0.8 60 films. Compared uniaxially platinized silicon, coercivity reduced...
The challenge of creating a graphene spin field effect transistor (spin-FET) demands magnetic gate dielectric material whose magnetization can be switched electrically. We have grown films Cr2O3 on top graphite and by pulsed laser deposition that shows this crucial functionality. demonstrate the are magnetoelectric poling them in combined electric fields then using force microscopy to observe spontaneous surface domain structure as function field. In addition, we show created conducting AFM...
We demonstrate the use of anomalous x-ray scattering constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively polar orientation polarity fraction unipolar mixed wurtzitic crystals. In one set experiments, gradual transition between c+ c− epitaxial ZnO films on sapphire as function MgO buffer layer thickness is monitored quantitatively, while second experiment, we map lateral homojunction GaN. The dispersion...
A two-step homoepitaxial growth process producing step-free surfaces on low dislocation density, Ga-polar ammonothermal GaN single crystals is described. Growth conducted under very supersaturation conditions where adatom incorporation occurs predominantly at step edges, and lateral strongly preferred. The achievable area limited by the substrate density. For with an average density of ∼1 × 104 cm−2, mesas up to 200 μm2 in size are achieved. These remarkable create a unique opportunity study...
Abstract
We determine the infrared absorption spectra of a gas due to evanescent plasmonic electromagnetic fields in system where surface interactions (physisorption and chemisorption) are demonstrably negligible. The host material, degenerate semiconductor CdO:Dy, has high mobility (366-450 cm2/(V s)) carrier density ((0.6-3.5) × 1020 cm-3), therefore supports low-loss plasmon resonances mid-IR. This high-mobility layer gives highest resolution observed conducting material infrared, higher than that...
We report the interface structures of CdO thin films on 001-MgO and 0001-Al2O3 substrates. Using aberration corrected scanning transmission electron microscopy, we show that epitaxial growth (001)-CdO∥(001)-MgO occurs with a lattice misfit greater than 10%. A high density dislocations is found to form. In combination molecular dynamics simulations, dislocation strain fields form overlap in very heterostructures MgO (<3 nm). On c-Al2O3 substrate, find grows surface normal 025. three...