A5088209484- 2D Materials and Applications
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Graphene research and applications
- Molecular Junctions and Nanostructures
- Quantum Dots Synthesis And Properties
- Quantum and electron transport phenomena
- Carbon Nanotubes in Composites
- Advanced Memory and Neural Computing
- Topological Materials and Phenomena
- Organic and Molecular Conductors Research
- Semiconductor Quantum Structures and Devices
- Phase-change materials and chalcogenides
- Advanced Sensor and Energy Harvesting Materials
- Strong Light-Matter Interactions
- Conducting polymers and applications
- Quantum Information and Cryptography
- Plasmonic and Surface Plasmon Research
- Astro and Planetary Science
- MXene and MAX Phase Materials
- Advanced NMR Techniques and Applications
- Inorganic Chemistry and Materials
- Semiconductor materials and devices
- Machine Learning in Materials Science
- Nanowire Synthesis and Applications
The University of Texas at Austin
2025
George Mason University
2016-2023
University of Maryland, College Park
2005-2022
National Institute of Standards and Technology
2022
Canadian Institute for Advanced Research
2022
University at Buffalo, State University of New York
2022
University of Fairfax
2020
United States Naval Research Laboratory
2013-2016
Trinity College Dublin
2016
University of Pennsylvania
2009-2015
We report broadband visible photoluminescence from solid graphene oxide, and modifications of the emission spectrum by progressive chemical reduction. The data suggest a gapping two-dimensional electronic system removal π-electrons. discuss possible mechanisms, propose that Kekule pattern bond distortions may account for observed behavior.
We study the crystal symmetry of few-layer 1T' MoTe2 using polarization dependence second harmonic generation (SHG) and Raman scattering. Bulk is known to be inversion symmetric; however, we find that broken for finite crystals with even numbers layers, resulting in strong SHG comparable other transition-metal dichalcogenides. Group theory analysis signals allows definitive assignment all modes clears up a discrepancy literature. The results were also compared density functional simulations...
Abstract Doping is a fundamental requirement for tuning and improving the properties of conventional semiconductors. Recent doping studies including niobium (Nb) molybdenum disulfide (MoS 2 ) tungsten (W) diselenide (MoSe have suggested that substitutional may provide an efficient route to tune type suppress deep trap levels 2D materials. To date, impact on structural, electronic, photonic in situ‐doped monolayers remains unanswered due challenges strong film substrate charge transfer,...
Background: Quantum information science and technology (QIST) has progressed significantly in the last decade, such that it is no longer solely domain of research labs, but now beginning to be developed for, applied in, industrial applications products. With emergence this new quantum industry, a workforce trained QIST skills knowledge needed. Research Questions: To help support education training workforce, universities colleges require type jobs available for their students what degrees...
Abstract The design and preparation of isotropic silver nanowire‐polystyrene composites is described, in which the nanowires have finite L/D (< 35) narrow distribution. These model allow dependence electrical percolation threshold, ϕ c , to be isolated for finite‐ particles. Experimental values decrease with increasing as predicted qualitatively by analytical models. However, quantitative agreement between experimental data both soft‐core core–shell models not achieved, because are...
Plasmon polaritons created by coupling optical cavity modes with plasmonic resonances offer widely tunable frequencies and strong light-matter interaction. While metallic nanocrystals (NCs) are compelling building blocks, existing approaches for their photonic integration not scalable, limiting systematic study potential applications. Here, we assemble colloidal tin-doped indium oxide NCs in a straightforward Salisbury screen configuration to realize an 'open' structure, where the infrared...
The structural polymorphism in transition metal dichalcogenides (TMDs) provides exciting opportunities for developing advanced electronics. For example, MoTe2 crystallizes the 2H semiconducting phase at ambient temperature and pressure, but transitions into 1T' semimetallic high temperatures. Alloying with WTe2 reduces energy barrier between these two phases, while also allowing access to Td Weyl semimetal phase. WxTe2 alloy system is therefore promising change memory technology. However,...
Phase-change memory (PCM) is a promising candidate for neuro-inspired, data-intensive artificial intelligence applications, which relies on the physical attributes of PCM materials including gradual change resistance states and multilevel operation with low drift. However, achieving these simultaneously remains fundamental challenge such as Ge2 Sb2 Te5 , most commonly used material. Here bi-directional changes ≈10× window using energy pulses are demonstrated in nanoscale devices based Ge4...
Traditionally, bulk nanocomposites of electrically conducting particles and insulating polymers have been categorized as either or when the nanoparticle concentration is below above percolation threshold, respectively. Meanwhile, thin-film polymer can exhibit resistive switching behavior appropriate for digital memory applications. Here, we present first report reversible in bulk, glassy nanocomposites. At compositions close to electrical threshold measured at low voltage, silver...
A pilot study explores relative contributions of extra-cerebral (scalp/skull) versus brain (cerebral) tissues to the blood flow index determined by diffuse correlation spectroscopy (DCS). Microvascular DCS measurements were made on head during baseline and breath-holding/hyperventilation tasks, both with without pressure. Baseline (resting) data enabled estimation signals their pressure dependencies. simple two-component model was used derive activated cerebral (CBF) signals, indices also...
The integration of InAs/GaAs quantum dots into nanophotonic cavities has led to impressive demonstrations cavity electrodynamics. However, these are primarily based on two-level excitonic systems. Efforts couple long-lived dot electron spin states with a only now succeeding. Here we report two-spin-cavity system, achieved by embedding an InAs molecule within photonic crystal cavity. With this system obtain singlet-triplet Λ-system where the ground-state splitting exceeds linewidth order...
$2H\text{\ensuremath{-}}\mathrm{Ta}{\mathrm{S}}_{2}$ undergoes a charge density wave (CDW) transition at ${T}_{\mathrm{CDW}}\ensuremath{\sim}75$ K, however key questions regarding the onset of CDW order remain under debate. In this study, we explore through combination temperature and excitation-dependent Raman spectroscopy, angle resolved photoemission spectroscopy (ARPES), functional theory (DFT). Below ${T}_{\mathrm{CDW}}$ identify two amplitude modes that redshift broaden with increasing...
Neutral and charged excitons (trions) in atomically-thin materials offer important capabilities for photonics, from ultrafast photodetectors to highly-efficient light-emitting diodes lasers. Recent studies of van der Waals (vdW) heterostructures comprised dissimilar monolayer have uncovered a wealth optical phenomena that are predominantly governed by interlayer interactions. Here, we examine the properties NbSe$_2$ - MoSe$_2$ vdW heterostructures, which provide an model system study...
Plasmon polaritons created by coupling optical cavity modes with plasmonic resonances offer widely tunable frequencies and strong light–matter interaction. While metallic nanocrystals (NCs) are compelling building blocks, existing approaches for their photonic integration not scalable, limiting systematic study potential applications. Here, we assemble colloidal tin-doped indium oxide NCs in a straightforward Salisbury screen configuration to realize an 'open' structure, where the infrared...
DNA-scaffolded molecular photonic wires (MPWs) displaying prearranged donor–acceptor chromophore pairs that engage in extended Förster resonance energy transfer (FRET) cascades represent an emerging nanoscale material with numerous potential applications data storage, encryption, and communications. For translation to such applications, these devices must first demonstrate robust performance high efficiencies over distances. Here, we report the optimization of FRET a 6-helix DNA origami...
We examine anharmonic contributions to the optical phonon modes in bulk Td-MoTe2 through temperature-dependent Raman spectroscopy. At temperatures ranging from 100 K 200 K, we find that all redshift linearly with temperature agreement Grüneisen model. However, below observe nonlinear frequency shifts some modes. demonstrate this behavior is consistent decay of an into multiple acoustic phonons. Furthermore, highest show large changes intensity and linewidth near T ≈ 250 correlate well Td→1T′...
The optical quality of site-controlled quantum dots is typically assessed by off-resonant photoluminescence spectroscopy, and emission linewidth the most common figure merit. Here, we combine resonance fluorescence spectroscopy to obtain a more complete picture embedded in charge injection device. Although resonant non-resonant linewidths are nearly as small those randomly nucleated dots, other properties show clear evidence influence from defects introduced nanofabrication process. We...
We combine experimental and theoretical methods to understand the impact of long-range Coulomb interactions on phonons excitons in ZrS<sub>x</sub>Se<sub>2−x</sub>.
Titanium-carbide-derived carbons (TiC-CDCs) are porous $s{p}^{2}$-bonded networks synthesized by exposing TiC to chlorine gas at an elevated temperature. The latter ``chlorination temperature'' adjusts the size of pores and carbon domains within this material. We perform magnetoresistance, electronic transport, superconducting quantum interference device magnetization measurements on TiC-CDC samples prepared different chlorination temperatures. Transport reveals a metal-insulator transition...
Crystal growth anisotropy in molecular beam epitaxy usually prevents deterministic nucleation of individual quantum dots when a thick GaAs buffer is grown over nanopatterned substrate. Here, we demonstrate how this can actually be used to mold sites for single on much thicker than has been achieved by conventional techniques. This approach greatly suppresses the problem defect-induced line broadening charge-tunable device, giving state-of-the-art optical linewidths system widely studied as...
A thorough understanding of native oxides is essential for designing semiconductor devices. Here, we report a study the rate and mechanisms spontaneous oxidation bulk single crystals ZrSxSe2–x alloys MoS2. oxidize rapidly, increases with Se content. Oxidation basal surfaces initiated by favorable O2 adsorption proceeds mechanism Zr–O bond switching, that collapses van der Waals gaps, facilitated progressive redox transitions chalcogen. The rate-limiting process formation out-diffusion SO2....