A5052450821- Graphene research and applications
- 2D Materials and Applications
- Surface and Thin Film Phenomena
- Topological Materials and Phenomena
- Electronic and Structural Properties of Oxides
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Quantum and electron transport phenomena
- Molecular Junctions and Nanostructures
- Advancements in Battery Materials
- Physics of Superconductivity and Magnetism
- Hydrogen Storage and Materials
- Machine Learning in Materials Science
- Iron-based superconductors research
- Particle accelerators and beam dynamics
- Graphene and Nanomaterials Applications
- Advanced Thermoelectric Materials and Devices
- Inorganic Chemistry and Materials
- Diamond and Carbon-based Materials Research
- Advanced Photocatalysis Techniques
- Strong Light-Matter Interactions
- Superconducting Materials and Applications
- Advanced Condensed Matter Physics
- MXene and MAX Phase Materials
- Rare-earth and actinide compounds
Center for Nanotechnology Innovation
2016-2025
Italian Institute of Technology
2015-2025
Lawrence Berkeley National Laboratory
2019-2024
University of California, Davis
2019-2022
National Enterprise for NanoScience and NanoTechnology
2014-2021
European Organization for Nuclear Research
2021
Istituto Nanoscienze
2017-2021
Istituto Officina dei Materiali
2021
Scuola Normale Superiore
2016-2020
University of Pisa
2015-2018
We use time- and angle-resolved photoemission spectroscopy (tr-ARPES) to investigate ultrafast charge transfer in an epitaxial heterostructure made of monolayer WS2 graphene. This combines the benefits a direct-gap semiconductor with strong spin-orbit coupling light-matter interaction those semimetal hosting massless carriers extremely high mobility long spin lifetimes. find that, after photoexcitation at resonance A-exciton WS2, photoexcited holes rapidly into graphene layer while electrons...
Abstract Charge transfer processes in two-dimensional van der Waals heterostructures enable upconversion of low energy photons and efficient charge carriers extraction. Here we use broadband ultrafast optical spectroscopy to track dynamics large-area 2D made epitaxial single-layer tungsten disulfide (WS 2 ) grown by chemical vapour deposition on graphene. Selective carrier photoexcitation graphene, with tunable near-infrared photon energies as 0.8 eV (i.e. lower than half the bandgap WS ),...
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...
We report the superlubric sliding of monolayer tungsten disulfide (WS2) on epitaxial graphene (EG) grown silicon carbide (SiC). Single-crystalline WS2 flakes with lateral size hundreds nanometers are obtained via chemical vapor deposition (CVD) EG. Microscopic and diffraction analyses indicate that WS2/EG stack is predominantly aligned zero azimuthal rotation. The present experiments show that, when perturbed by a scanning probe microscopy (SPM) tip, prone to slide over surfaces at room...
Stacking van der Waals crystals allows for the on-demand creation of a periodic potential landscape to tailor transport quasiparticle excitations. We investigate diffusion photoexcited electron–hole pairs, or excitons, at interface WS2/WSe2 heterostructure over wide range temperatures. observe appearance distinct interlayer excitons parallel and antiparallel stacking track their through spatially temporally resolved photoluminescence spectroscopy from 30 250 K. While measured exciton...
This work reports an electronic and micro-structural study of appealing system for optoelectronics: tungsten disulphide (WS<sub>2</sub>) on epitaxial graphene (EG) SiC(0001).
Pt-functionalized graphene shows promise for near-ambient hydrogen storage due to graphene's potential as a host and platinum's role catalyst the evolution reaction spillover effect. This study explores Pt cluster formation on epitaxial its suitability storage. Scanning Tunneling Microscopy reveals two growth pathways. Initially, up ∼1 ML of coverage, tends randomly disperse cover surface, whereas height remains unchanged. Beyond coverage 3 ML, nucleation new layers existing clusters becomes...
Graphene rippled at the nanoscale level is gathering attention for advanced applications, especially in field of nanoelectronics and hydrogen storage. Convexity enhanced reactivity toward H was demonstrated on naturally corrugated graphene grown by Si evaporation SiC, which makes this system a platform fundamental studies effects rippling. In work, we report density functional theory study model specifically designed to mimic SiC. We first supercell geometry configuration that better...
We present a systematical study via scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) on the effect of exposure lithium graphene silicon carbide (SiC). have investigated Li deposition both epitaxial monolayer buffer layer surfaces Si face SiC. At room temperature, immediately intercalates at interface between SiC substrate transforms into quasi-free-standing graphene. This conclusion is substantiated by LEED STM evidence. show that intercalation occurs through...
By exhibiting a measurable bandgap and exotic valley physics, atomically-thick tungsten disulfide (WS2) offers exciting prospects for optoelectronic applications. The synthesis of continuous WS2 films on other two-dimensional (2D) materials would greatly facilitate the implementation novel all-2D photoactive devices. In this work we demonstrate scalable growth graphene hexagonal boron nitride (h-BN) via chemical vapor deposition (CVD) approach. Spectroscopic microscopic analysis reveal that...
Unconventional superconductors have Cooper pairs with lower symmetries than in conventional superconductors. In most unconventional superconductors, the additional symmetry breaking occurs relation to typical ingredients such as strongly correlated Fermi liquid phases, magnetic fluctuations, or strong spin-orbit coupling noncentrosymmetric structures. this article, we show that time-reversal superconductor LaNiGa$_2$ is enabled by its previously unknown topological electronic band structure....
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 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,...
Discovery of 2D Rb-ordered interlayers between monolayer graphene and the buffer layer on SiC(0001): a multi-technique study morphology, properties, stability.
A patterned-growth, scalable fabrication strategy allows photodetectors with good electrical properties that show fast response red light and persistent photocurrent blue light.
Excitons are spin integer particles that predicted to condense into a coherent quantum state at sufficiently low temperature. Here by using photocurrent imaging we report experimental evidence of formation and efficient transport non-equilibrium excitons in Bi2-xSbxSe3 nanoribbons. The distributions independent electric field, indicating photoexcited electrons holes form excitons. Remarkably, these can over hundreds micrometers along the topological insulator (TI) nanoribbons before...
${\mathrm{Co}}_{3}{\mathrm{Sn}}_{2}{\mathrm{S}}_{2}$ is a magnetic Weyl semimetal, in which ferromagnetic ordering at 177 K predicted to stabilize points. We perform temperature and spatial dependent angle-resolved photoemission spectroscopy measurements through the Curie (${T}_{c}$), show large band shifts renormalization concomitant with onset of magnetism. argue that evolves from Mott ferromagnet below ${T}_{c}$ correlated metallic state above ${T}_{c}$. To understand magnetism, we derive...
Nickel nanoparticles (Ni NPs), thanks to their peculiar properties, are interesting materials for many applications including catalysis, hydrogen storage, and sensors. In this work, Ni NPs synthesized in aqueous solution by a simple rapid procedure with cetyltrimethylammonium bromide (CTAB) as capping agent, extensively characterized dynamic light scattering (DLS), scanning electron microscopy (SEM), atomic force (AFM). We investigated shape, dimension, distribution on the surfaces of SiO2...
Alkali metal intercalation of graphene layers has been particular interest due to potential applications in electronics, energy storage, and catalysis. Rubidium (Rb) is one the largest alkali metals less investigated as intercalant. Here, we report a systematic investigation, with multi-technique approach, phase formation Rb under epitaxial monolayer on SiC(0001). We explore wide space two control parameters: density (i.e., deposition time) sample temperature room- low-temperature). reveal...
OPINION article Front. Mater., 30 January 2015Sec. Mechanics of Materials Volume 2 - 2015 | https://doi.org/10.3389/fmats.2015.00003
Transparent conducting oxides (TCO) have integral and emerging roles in photovoltaic, thermoelectric energy conversion, more recently, photocatalytic systems. The functional properties of TCOs, thus their role these applications, are often mediated by the bulk electronic band structure but also strongly influenced native surface 2D electron gas (2DEG), particularly under operating conditions. This study investigates 2DEG, its response to changes chemistry, at (111) model TCO In2 O3 , through...
Efficient light harvesting devices need to combine strong absorption in the visible spectral range with efficient ultrafast charge separation. These features commonly occur novel ultimately thin van der Waals heterostructures type II band alignment. Recently, separation was also observed monolayer WS 2 /graphene I Here we use time- and angle-resolved photoemission spectroscopy show that occurs at interface between bilayer graphene indicating indirect gap of does not affect transfer layer....