A5009284437- Molecular Junctions and Nanostructures
- 2D Materials and Applications
- Quantum Dots Synthesis And Properties
- Surface and Thin Film Phenomena
- Nanowire Synthesis and Applications
- Electronic and Structural Properties of Oxides
- Graphene research and applications
- Surface Chemistry and Catalysis
- Biblical Studies and Interpretation
- X-ray Diffraction in Crystallography
- Machine Learning in Materials Science
- Pentecostalism and Christianity Studies
- Crystallization and Solubility Studies
- MXene and MAX Phase Materials
- Mormonism, Religion, and History
- Advanced Materials Characterization Techniques
- Christian Theology and Mission
- Advanced Electron Microscopy Techniques and Applications
- Advanced biosensing and bioanalysis techniques
- Force Microscopy Techniques and Applications
- Nanocluster Synthesis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Advanced Condensed Matter Physics
- Religion, Spirituality, and Psychology
- Neural Networks and Reservoir Computing
Lawrence Berkeley National Laboratory
2021-2025
Dartmouth College
2023
California NanoSystems Institute
2012-2020
University of California, Los Angeles
2012-2020
California Institute of Technology
2015
The University of Texas at San Antonio
2011
Pennsylvania State University
2010
We employ mixed self-assembled monolayers of carboranethiols to alter the work function gold and silver systematically. use isomers symmetric carboranethiol cage molecules vary molecular dipole moments directions, which enable tunability over a wide range with minimal alterations in surface energy. Mixed provide an ideal platform for study fabrication solution-processed organic field-effect transistors; improved device performance is demonstrated by interface engineering.
Abstract Point defects in two-dimensional materials are of key interest for quantum information science. However, the parameter space possible is immense, making identification high-performance very challenging. Here, we perform high-throughput (HT) first-principles computational screening to search promising within WS 2 , which present localized levels band gap that can lead bright optical transitions visible or telecom regime. Our computed database spans more than 700 charged formed...
Abstract Forming heavily‐doped regions in 2D materials, like graphene, is a steppingstone to the design of emergent devices and heterostructures. Here, selective‐area approach presented tune work‐function carrier density monolayer graphene by spatially synthesizing sub‐monolayer gallium beneath 2D‐solid. The localized metallic formed via precipitation from an underlying diamond‐like carbon (DLC) film that implanted with gallium‐ions. By controlling interfacial process annealing temperature,...
When alkanethiolate self-assembled monolayers on Au{111} are exchanged with alkaneselenols from solution, replacement of thiolates by selenols is rapid and complete, well described perimeter-dependent island growth kinetics. The monolayer structures change as selenolate coverage increases, being epitaxial consistent the initial thiolate structure to characteristic structures. At room temperature at positive sample bias in scanning tunneling microscopy, selenolate–gold attachment labile,...
Abstract Individual atomic defects in 2D materials impact their macroscopic functionality. Correlating the interplay is challenging, however, intelligent hyperspectral scanning tunneling spectroscopy (STS) mapping provides a feasible solution to this technically difficult and time consuming problem. Here, dense spectroscopic volume collected autonomously via Gaussian process regression, where convolutional neural networks are used tandem for spectral identification. Acquired data enable...
We demonstrate the use of "holey" graphene as a mask against molecular adsorption. Prepared porous is transferred onto Au{111} substrate, annealed, and then exposed to dilute solutions 1-adamantanethiol. In pores lattice, we find islands organized, self-assembled molecules. The bare Au in can be regenerated by postdeposition annealing, new molecules region. Graphene serve robust, patternable deposition monolayers.
We investigate the electronic properties of a graphene and α-ruthenium trichloride (α-RuCl3) heterostructure using combination experimental techniques. α-RuCl3 is Mott insulator Kitaev material. Its with has gained increasing attention due to its potential applicability in novel optoelectronic devices. By spatially resolved photoemission spectroscopy low-energy electron microscopy, we are able provide direct visualization massive charge transfer from α-RuCl3, which can modify both materials,...
Single-molecule measurements of complex biological structures such as proteins are an attractive route for determining the large number important biomolecules that have proved refractory to analysis through standard techniques X-ray crystallography and nuclear magnetic resonance. We use a custom-built low-current scanning tunneling microscope image peptide at single-molecule scale in model forms β sheets, structural motif common protein misfolding diseases. successfully differentiate between...
Carboranethiol molecules self-assemble into upright molecular monolayers on Au{111} with aligned dipoles in two dimensions. The positions and offsets of each molecule's geometric apex local dipole moment are measured correlated sub-Ångström precision. Juxtaposing simultaneously acquired images, we observe monodirectional between the apexes extrema. We determine orientations using efficient new image analysis techniques find to be highly defect tolerant, crossing domain boundaries substrate...
Tip-enhanced photoluminescence (TRPL) is a powerful technique for spatially and spectrally probing local optical properties of 2-dimensional (2D) materials that are modulated by the heterogeneities, revealing inaccessible dark states due to bright state overlap in conventional far-field microscopy at room temperature. While scattering-type near-field probes have shown potential selectively enhance reveal exciton emission, their technical complexity sensitivity can pose challenges under...
We use simple acid-base chemistry to control the valency in self-assembled monolayers of two different carboranedithiol isomers on Au{111}. Monolayer formation proceeds via Au-S bonding, where manipulation pH prior or during deposition enables assembly dithiolate species, monothiol/monothiolate combination. Scanning tunneling microscopy (STM) images identify distinct binding modes each unmodified monolayer, simultaneous spectroscopic imaging confirms dipole offsets for mode. Density...
We report a complex, dynamic double lattice for 1-adamantaneselenolate monolayers on Au{111}. Two lattices coexist, revealing two different binding modes selenols gold: molecules at bridge sites have lower conductance than three-fold hollow sites. The monolayer is dynamic, with switching reversibly between the site-dependent states. Monolayer dynamics enable adsorbed to reorganize according underlying gold electronic structure over long distances, which facilitates emergence of...
The p-carborane cluster analogue of p-mercaptobenzoic acid, 1-HS-12-COOH-1,12-C2B10H10, has been synthesized and characterized using nuclear magnetic resonance spectroscopy, single-crystal X-ray diffraction analysis, quantum-chemical calculations, scanning tunneling microscopy. structure selected packing aspects are discussed presented in comparison with the two-dimensional periodic arrangements. Scanning micrographs, recorded under ambient conditions, used to compare pure monolayers...
We map buried hydrogen-bonding networks within self-assembled monolayers of 3-mercapto-N-nonylpropionamide on Au{111}. The contributing interactions include the S-Au bonds at substrate surface and plane linear hydrogen bonds. Both are simultaneously mapped with submolecular resolution, in addition to exposed interface, determine orientations molecular segments directional bonding. Two-dimensional mode-decomposition techniques used elucidate directionality these networks. find that...
Book Review| April 01 1993 Footwashing in John 13 and the Johannine Community Community, Christopher Thomas. Charles H. Talbert Search for other works by this author on: This Site Google Journal of Biblical Literature (1993) 112 (1): 156–158. https://doi.org/10.2307/3267889 Cite Icon Share Facebook Twitter LinkedIn MailTo Permissions Citation Talbert; Community. 1 January 1993; doi: Download citation file: Zotero Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex...
The structure and function of self-assembled monolayers (SAMs) at the nanoscale are determined by steric electronic effects their building blocks. Carboranethiol molecules form pristine that provide tunable two-dimensional systems to probe lateral interfacial interactions. Additional ω-functionality, such as carboxyl groups, can be introduced change properties exposed surfaces. Here, two geometrically similar isomeric m-carborane analogues m-mercaptobenzoic acid, 1-COOH-7-SH-1,7-C2B10H10...
Abstract Tomonaga-Luttinger liquid (TLL) behavior in one-dimensional systems has been predicted and shown to occur at semiconductor-to-metal transitions within two-dimensional materials. Reports of mirror twin boundaries (MTBs) hosting a Fermi or TLL have suggested dependence on the underlying substrate, however, unveiling physical details electronic contributions from substrate require cross-correlative investigation. Here, we study formation MTBs defectively engineered WS 2 atop graphene,...
<title>Abstract</title> Point defects in two-dimensional materials are of key interest for quantum information science. However, the space possible is immense, making identification high-performance extremely challenging. Here, we perform high-throughput (HT) first-principles computational screening to search promising within WS<sub>2</sub>, which present localized levels band gap that can lead bright optical transitions visible or telecom regime. Our computed database spans more than 700...
We have utilized tunneling electrons and thiophene adsorption to draw deuterium (D) from within the single-crystal bulk beneath Pd{110} up subsurface sites. found local faceting induced by this process, determined energy threshold of drawing D sites be 0.38 ± 0.02 eV. show that these facets propagate along ⟨11̅0⟩ direction substrate, adopts (1 × 1) surface reconstruction on facets, yet maintains paired row 2) structure unaffected regions. After producing D, facet plane tilts 3.2 0.8° off...
Abstract We investigate the interplay between vertical tunneling and lateral transport phenomena in electrically contacted van der Waals heterostructures made from monolayer MoS 2 , hBN, graphene. compare data taken by low-temperature scanning spectroscopy to results room-temperature conductive atomic force on with sulfur vacancies varying hBN layers. show that for thick barrier layers, where currents into substrate are suppressed, a side-contact still enables addressing defect states...
Paul S. Weiss and co-workers report on page 302 progress toward the precise assembly measurement of photoresponsive molecules in well-defined environments. The cover depicts coordinated photoisomerization a one-dimensional chain assembled within domain boundary self-assembled monolayer, measured with scanning tunneling microscope.
The Pd(II) atom in the complex cation of title compound, [PdCl(C(21)H(16)N(4))]Cl, is coordinated by three N atoms derived from terpyridine ligand and a chloride ion, which define distorted PdClN(3) square-planar coordination geometry. In crystal, presence N-H⋯Cl hydrogen bonds involving amino H anions link two cations into four-ion aggregate via centrosymmetric eight-membered [⋯H-N-H⋯Cl](2) synthons. Layers are inter-spersed with stabilization provided C-H⋯Cl inter-actions both Cl atoms, as...