Article
Chemistry, Physical
V. Carnevali, A. Sala, P. Biasin, M. Panighel, G. Comelli, M. Peressi, C. Africh
Summary: The electronic properties of graphene can be modified by local interaction with a metal substrate. This article proposes a reliable method of evaluating the interaction between graphene and substrate by testing the tunneling current. This method expands the capabilities of standard STM systems for studying graphene/substrate complexes.
Article
Chemistry, Multidisciplinary
Yi-Ying Sung, Harmina Vejayan, Christopher J. Baddeley, Neville V. Richardson, Federico Grillo, Renald Schaub
Summary: On-surface synthesis with designer precursor molecules is an effective method for preparing graphene nanoribbons (GNRs) with tunable electronic properties. The band gap of GNRs doped with heteroatoms remains unchanged, but hydrogenation can engineer a tunable band gap. Surface-confined hydrogenation studies on 7-armchair GNRs grown on Au(111) surfaces reveal a self-limited hydrogenation process. The electronic properties of the GNR/Au(111) system can be modified by edge and basal-plane hydrogenation, and a mechanism for the hydrogenation process is proposed.
Article
Physics, Multidisciplinary
Fumiya Mukai, Kota Horii, Ryoya Ebisuoka, Kenji Watanabe, Takashi Taniguchi, Ryuta Yagi
Summary: The study focuses on the Moire superlattice of twisted h-BN/AB-stacked tetralayer graphene heterostructures, revealing that band gaps arise due to Fermi surface nesting at specific angles. The Moire superlattice of multilayer graphene exhibits features influenced by the anisotropic Fermi surface affected by the superlattice structure, with resistivity peaks showing a complex dependence on the perpendicular electric field.
COMMUNICATIONS PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Frederic Joucken, Cristina Bena, Zhehao Ge, Eberth Quezada-Lopez, Sarah Pinon, Vardan Kaladzhyan, Takashi Taniguchi, Kenji Watanabe, Aires Ferreira, Jairo J. R. Velasco
Summary: Graphite commonly used for preparing graphene devices contains a significant amount of native defects, impacting the electronic properties of Bernal-stacked bilayer graphene. The distribution of scattering vectors shows a clear carrier density dependence. The dilute native defects identified in the study are found to be an important extrinsic source of scattering, influencing charge carrier mobility at low temperatures.
Article
Chemistry, Physical
Yin Yin, Guanyong Wang, Chen Liu, Haili Huang, Jiayi Chen, Jiaying Liu, Dandan Guan, Shiyong Wang, Yaoyii Li, Canhua Liu, Hao Zheng, Jinfeng Jia
Summary: A moire superlattice has been discovered in topological insulators, showing a periodic modulation on the electronic structure. This study demonstrates that the rotation angles between Sb2Te3 film and graphene substrate can be strongly influenced by substrate temperature, leading to different moire patterns with varying levels of complexity. Comparing dI/dV curves from Sb2Te3 films with different moire patterns suggests that the superstructure can provide degrees of freedom in modifying electronic structure, stimulating further research on the moire modulation in topological insulators.
Article
Multidisciplinary Sciences
Alexander Kerelsky, Carmen Rubio-Verdu, Lede Xian, Dante M. Kennes, Dorri Halbertal, Nathan Finney, Larry Song, Simon Turkel, Lei Wang, Kenji Watanabe, Takashi Taniguchi, James Hone, Cory Dean, Dmitri N. Basov, Angel Rubio, Abhay N. Pasupathy
Summary: This study demonstrates the formation of emergent correlated phases in multilayer rhombohedral graphene without the need for twisted van der Waals layers. The study shows that two layers of bilayer graphene twisted by a tiny angle can host large regions of uniform rhombohedral four-layer graphene with a sharp van Hove singularity. Furthermore, the study suggests that the broken symmetry state in ABCA graphene could be attributed to a charge-transfer excitonic insulator or a ferrimagnet.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Multidisciplinary
Ya-Ning Ren, Mo-Han Zhang, Chao Yan, Yu Zhang, Lin He
Summary: This study focuses on magneto-oscillations in 2D electron systems and their application in different stacked graphene layers. It demonstrates that STM can locally measure these oscillations, providing a convenient and effective method for studying such materials.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Article
Electrochemistry
Thi Mien Trung Huynh, Tan Lam Nguyen, Thanh Hai Phan
Summary: Robust engineering of surface properties is crucial for improving the overall physicochemical behaviors of layered materials like graphene for high-end applications. In this study, covalent functionalization of graphitic surfaces was achieved through electrografting with 4-(1H-1,2,4-triazol-1-ylmethyl) diazonium. The degree of functionalization depended on the concentration of 4-TYD, with full monolayer coverage achieved at 1 mM concentration. The electrografted layer could be removed by thermal annealing, providing a controlled approach for anchoring bioactive compounds onto graphene and other 2D materials.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Yohan Kim, Huijun Han, Da Luo, Rodney S. Ruoff, Hyung-Joon Shin
Summary: The structural and electronic properties of graphene grown on catalytic metal surfaces are significantly modified due to the interaction between graphene and the substrate. To minimize the influence of the metal substrate, NaCl thin films can be introduced as intercalation layers to decouple graphene from the metal substrate, resulting in quasi-freestanding graphene.
Article
Chemistry, Multidisciplinary
Daniel J. Rizzo, Sara Shabani, Bjarke S. Jessen, Jin Zhang, Alexander S. McLeod, Carmen Rubio-Verdu, Francesco L. Ruta, Matthew Cothrine, Jiaqiang Yan, David G. Mandrus, Stephen E. Nagler, Angel Rubio, James C. Hone, Cory R. Dean, Abhay N. Pasupathy, D. N. Basov
Summary: The researchers successfully created nanometer-scale lateral p-n junctions using graphene/alpha-RuCl3 heterostructure near graphene nanobubbles. Through STM/STS and s-SNOM techniques, they investigated the electronic and optical responses of nanobubble p-n junctions, achieving p-n junctions with a width of around 3 nm and an electric field of approximately 10(8) V/m. The study also utilized ab initio density functional theory calculations to corroborate experimental data and provide insights into charge transfer mechanisms in 2D materials.
Article
Chemistry, Multidisciplinary
Qiucheng Li, Xiaolong Liu, Eden B. Aklile, Shaowei Li, Mark C. Hersam
Summary: The study reports the self-assembly of mixed-dimensional lateral heterostructures consisting of 2D metallic borophene and 1D semiconducting armchair-oriented graphene nanoribbons (aGNRs). The systematic study and refinement of on-surface polymerization process from monomers to organometallic intermediates to demetallization result in borophene/aGNR lateral heterojunctions with structurally and electronically abrupt interfaces, providing insight for precise nanoelectronics.
Article
Chemistry, Multidisciplinary
Leonard Desvignes, Vasily S. Stolyarov, Marco Aprili, Freek Massee
Summary: The text highlights the importance of manipulating individual atoms and molecules using a scanning tunneling microscope for the development of atomic-scale devices and structures, particularly molecular motors. It also introduces the controlled manipulation of a rotor in Fe doped Bi2Se3, where current into the rotor is finely tuned with voltage to achieve directional switching.
Article
Chemistry, Multidisciplinary
Jesse Balgley, Jackson Butler, Sananda Biswas, Zhehao Ge, Samuel Lagasse, Takashi Taniguchi, Kenji Watanabe, Matthew Cothrine, David G. Mandrus, Jairo Velasco, Roser Valenti, Erik A. Henriksen
Summary: In this study, we demonstrate ultrasharp lateral p-n junctions in graphene using electronic transport, scanning tunneling microscopy, and first-principles calculations. These junctions are formed at the boundary between differently doped regions of a graphene sheet, with one side being intrinsic and the other side being charge-doped by proximity to an alpha-RuCl3 flake. Our results show potential variations on a sub 10 nm length scale in heterostructures of graphene, hexagonal boron nitride, and alpha-RuCl3. First-principles calculations reveal a sharp decay of charge-doping from the edge of the alpha-RuCl3 flake within just a few nanometers.
Article
Chemistry, Multidisciplinary
Renan Villarreal, Pin-Cheng Lin, Fahim Faraji, Nasim Hassani, Harsh Bana, Zviadi Zarkua, Maya N. Nair, Hung-Chieh Tsai, Manuel Auge, Felix Junge, Hans C. Hofsaess, Stefan De Gendt, Steven De Feyter, Steven Brems, E. Harriet Ahlgren, Erik C. Neyts, Lucian Covaci, Francois M. Peeters, Mehdi Neek-Amal, Lino M. C. Pereira
Summary: The study found that the size ratio of nanobubbles formed on graphene surfaces is influenced by the bubble radius, with larger ratios observed when the radius approaches 1 nm. The stability and size ratio of the bubbles are also dependent on the substrate and trapped elements, indicating a correlation with the atomic compressibility of the noble gases and adhesion energies between materials.
Article
Physics, Multidisciplinary
M. Omidian, J. Brand, N. Neel, S. Crampin, J. Kroeger
Summary: Epitaxially grown Fe nanostructures on Pb(111) were studied using low-temperature scanning tunneling microscopy and spectroscopy. The Fe assemblies were categorized into two groups based on their electronic behavior near the Fermi energy. One group exhibited a metallic behavior with a wide energy gap of 0.7 eV that remained temperature-independent. These Fe islands lacked the superconductivity proximity effect in their interior. The other group displayed a metallic behavior at the Fermi level, with the substrate superconducting phase locally entering these islands, evidenced by sharp resonance at the Fermi energy indicating possible Andreev reflection at the magnet-superconductor interface.
NEW JOURNAL OF PHYSICS
(2023)
Article
Chemistry, Physical
Barbara A. J. Lechner, Xiaofeng Feng, Peter J. Feibelman, Jorge I. Cerda, Miquel Salmeron
JOURNAL OF PHYSICAL CHEMISTRY B
(2018)
Article
Multidisciplinary Sciences
Jun Wang, Liang Yu, Lin Hu, Gang Chen, Hongliang Xin, Xiaofeng Feng
NATURE COMMUNICATIONS
(2018)
Article
Chemistry, Physical
Lin Hu, Asim Khaniya, Jun Wang, Gang Chen, William E. Kaden, Xiaofeng Feng
Article
Chemistry, Physical
Jun Wang, Asim Khaniya, Lin Hu, Melanie J. Beazley, William E. Kaden, Xiaofeng Feng
JOURNAL OF MATERIALS CHEMISTRY A
(2018)
Article
Chemistry, Physical
Lorianne R. Shultz, Lin Hu, Konstantin Preradovic, Melanie J. Beazley, Xiaofeng Feng, Titel Jurca
Review
Chemistry, Physical
Lin Hu, Zhuo Xing, Xiaofeng Feng
ACS ENERGY LETTERS
(2020)
Article
Chemistry, Physical
Lorianne R. Shultz, Lin Hu, Xiaofeng Feng, Titel Jurca
Article
Multidisciplinary Sciences
Zhuo Xing, Lin Hu, Donald S. Ripatti, Xun Hu, Xiaofeng Feng
Summary: The study found that a hydrophobic microenvironment can significantly enhance CO2 gas-diffusion electrolysis efficiency. Furthermore, a balanced gas/liquid microenvironment can reduce the diffusion layer thickness, accelerate CO2 mass transport, and increase CO2 local concentration for electrolysis.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Zhuo Xing, Xun Hu, Xiaofeng Feng
Summary: Tuning the microenvironment of Bi-based catalyst in a gas-diffusion-electrode (GDE) by adding hydrophobic polytetrafluoroethylene (PTFE) nanoparticles substantially enhances CO2 electrolysis, achieving high formate production rates and CO2 conversion efficiencies.
ACS ENERGY LETTERS
(2021)
Article
Chemistry, Applied
Zhuo Xing, Kaige Shi, Xun Hu, Xiaofeng Feng
Summary: Electrochemical reduction of CO2 to value-added chemicals using renewable electricity is crucial for sustainable fuel production and carbon neutrality. This review highlights insights into the microenvironment in the catalyst layer for CO2 electrolysis, providing important guidelines for the design of key components in CO2 electrolysis.
JOURNAL OF ENERGY CHEMISTRY
(2022)
Article
Chemistry, Physical
Lin Hu, Hemanth Somarajan Pillai, Corbin Feit, Kaige Shi, Zhengning Gao, Parag Banerjee, Hongliang Xin, Xiaofeng Feng
Summary: In this study, Ru nanoparticles prepared by atomic layer deposition were found to exhibit size-dependent activity, with the highest specific activity observed on 3.8 nm particles and a 5-fold decrease in activity on 8.4 nm particles. Density functional theory calculations and free energy analysis identified the Ru D-5 step site on 4 nm particles as the active site for NRR on Ru.
ACS ENERGY LETTERS
(2022)
Article
Chemistry, Physical
Lorianne R. Shultz, Zackary S. Parsons, Melanie Beazley, Xiaofeng Feng, Titel Jurca
Summary: In this study, the mechanism of methylene blue reduction using Pt/C nanoparticles was investigated. Through a multiparametric study, the factors impacting the reaction were analyzed, including reaction kinetics, pH, dissolved oxygen, and catalyst and reductant loading. It was found that the H-2 evolution and reoxidation sequences were the limiting steps for the reduction of methylene blue. By optimizing the reductant concentration and catalyst loading, N-2 purging, and restricting O-2 redissolution, a highly competitive activity parameter of 25,740 min(-1) g(Pt)(-1) L was achieved.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Zhuo Xing, Kaige Shi, Zackary S. Parsons, Xiaofeng Feng
Summary: Heteroatom doping is widely used in electrocatalyst design to improve performance, but it can also affect the wetting properties of the catalyst microenvironment. This study investigates the interplay between active sites and microenvironment in the electrochemical synthesis of H2O2 on doped carbon. The results show that while doping increases the intrinsic activity for H2O2 production, the optimal production rate is achieved with a moderately doped carbon catalyst due to changes in wetting characteristics.
Article
Chemistry, Physical
Kaige Shi, Zackary S. Parsons, Xiaofeng Feng
Summary: The wetting properties of the catalyst microenvironment have a significant impact on the electrocatalytic performance of gas-evolving reactions. By controlling the microenvironment using oxygen-doped and fluorine-doped carbon supports, the activity of carbon-supported Pt nanocatalysts for N2H4 electro-oxidation was increased by 123% and 46% respectively.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Physical
Zhuanghe Ren, Kaige Shi, Xiaofeng Feng
Summary: Cu-based catalysts have been investigated for the electrochemical nitrate reduction reaction (NO3RR), but the activity and selectivity of Cu metal for the NO3RR are still unclear. This study reveals the significance of Cu facet exposure, nitrate concentration, and electrode surface area on the NO3RR. A polished Cu foil with more exposed Cu(100) facets exhibits higher activity and selectivity for the NO3RR to NH3 compared to a wet-etched Cu foil. The NH3 selectivity shows no dependence on nitrate concentration but increases with the Cu electrode area, attributed to the enhanced conversion of intermediately produced NO2(-) to NH3 on a larger electrode, as confirmed by isotope labeling experiments. Mechanistic insights from this work can guide the rational design of NO3RR electrocatalysts.
ACS ENERGY LETTERS
(2023)
