Article
Chemistry, Physical
Nadire Nayir, Mert Y. Sengul, Anna L. Costine, Petra Reinke, Siavash Rajabpour, Anushka Bansal, Azimkhan Kozhakhmetov, Joshua Robinson, Joan M. Redwing, Adri van Duin
Summary: This study investigates the defect-mediated surface interactions of gallium metals and trimethyl-gallium molecules with graphene using a combination of theory and experiments. The results reveal the presence of defects in graphene, which act as pathways for gallium intercalation. The study shows that the adsorption of gallium and trimethyl-gallium on graphene is strongly influenced by the presence and size of defects, and these defects catalyze surface reactions.
Article
Chemistry, Physical
Francois Aguillon, Andrei G. Borisov
Summary: In this work, the impact of atomic scale lattice imperfections on the nonlinear response of graphene nanoflakes enhanced by resonance between electromagnetic fields and localized plasmon is investigated theoretically. Using the many-body time-dependent density matrix approach, it is found that a single defect in nanoflakes with thousands of carbon atoms can significantly affect the nonlinear hyperpolarizability and override symmetry constraints. This effect cannot be captured by the relaxation time approximation in quantum or classical frameworks. The results of this study have important implications for the design of nonlinear graphene devices.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ali Mostaed, Brant Walkley, Monica Ciomaga Hatnean, Geetha Balakrishnan, Martin R. Lees, Richard Beanland, Derek C. Sinclair, Ian M. Reaney
Summary: This study demonstrates the analysis of oxides using aberration corrected scanning transmission electron microscopy and reveals that the shape and contrast of visible atomic columns in annular dark-field images are affected by the presence of nearby low atomic number atoms. In addition, the resolution of light atoms in oxides using this method is successful and applicable to materials containing both light and heavy elements.
Article
Chemistry, Physical
Rina Ibragimova, Patrick Rinke, Hannu-Pekka Komsa
Summary: This study investigates the formation energies of metal, carbon, and nitrogen vacancies in MXene materials using first-principles calculations. The results show significant differences in the formation energies of metal vacancies under different surface functionalizations and environments. Carbon and nitrogen vacancies are found to be more prevalent in oxygen-functionalized surfaces. The study also highlights the influence of pH value and electrode potential on vacancy formation.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Liu Chu, Jiajia Shi, Eduardo Souza de Cursi
Summary: In this paper, a method for identifying atomic vacancy defects in graphene based on resonant frequency fingerprints is provided. The study establishes the implicit relationship between the locations of atomic vacancy defects and the resonant frequencies of graphene using a sample database. The work aims to explore the feasibility of atomic vacancy defects identification and provides supplementary information for non-destructive defect detection and identification in nanomaterials.
Article
Chemistry, Multidisciplinary
Anna Roslawska, Pablo Merino, Abhishek Grewal, Christopher C. Leon, Klaus Kuhnke, Klaus Kern
Summary: By using a low-temperature scanning tunneling microscope, fluctuations in plasmonic electroluminescence at the single-atom limit were studied, revealing changes in electroluminescence intensity due to spontaneous modifications from minute atomic rearrangements at or near the contact. This research is relevant for understanding the processes leading to spontaneous intensity variations in plasmon-enhanced atomic-scale spectroscopies.
Article
Chemistry, Multidisciplinary
Ryo Ishikawa, Riku Tanaka, Kazuaki Kawahara, Naoya Shibata, Yuichi Ikuhara
Summary: The text discusses the importance of metal oxide surfaces and the direct determination of 3D atomic structures using depth sectioning of atomic-resolution annular dark-field scanning transmission electron microscopy. By statistically analyzing column by column depth profiles, researchers achieved high depth resolution at the entrance surface, providing fertile ground for advancements in surface science.
Article
Physics, Applied
Adrian Chmielewski, Ziling Deng, Muad Saleh, Jani Jesenovec, Wolfgang Windl, Kelvin Lynn, John McCloy, Nasim Alem
Summary: The study investigates the atomic and electronic structure of a Hf-doped beta-gallium oxide crystal and finds that Hf dopants prefer octahedral sites and have little impact on the crystal structure. The bandgap values of Hf-doped beta-Ga2O3 are similar to those of unintentionally doped crystals, making Hf an excellent dopant candidate.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Mojtaba Rezaei, Luis Francisco Villalobos, Kuang-Jung Hsu, Kumar Varoon Agrawal
Summary: This article reports a method for controlling graphene edges and vacancies, which is desired for various applications. The researchers found that CO2 can effectively control the etching rate without causing vacancy nucleation, showing great potential for practical applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Damla Yesilpinar, Martin Vondracek, Patrik Cermak, Harry Monig, Jaromir Kopecek, Ondrej Caha, Karel Carva, Cestmir Drasar, Jan Honolka
Summary: We investigated the effect of low concentrations of iron on the physical properties of SnS van der Waals crystals grown from the melt. Through scanning tunneling microscopy (STM) and photoemission spectroscopy, we studied Fe-induced defects and observed an electron doping effect in the band structure of the native p-type SnS semiconductor. Our results showed that Fe preferentially occupies donor-like interstitial Fe-int sites in close proximity to V-Sn defects along the high-symmetry c-axis of SnS, leading to a reduction of p-type carrier concentrations.
Article
Materials Science, Multidisciplinary
Yueqi Hu, Ping Huang, Fei Wang
Summary: This study investigates the influence of graphene microstructure on the irradiation resistance of graphene/metal composites using molecular dynamics simulation. The results show that the presence of intrinsic defects in multi-layer graphene enhances its ability to absorb irradiation-induced defects and store helium bubbles, compared to perfect single-layer graphene.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Sujuan Ding, Fang Lin, Chuanhong Jin
Summary: Quantitative and statistical analysis of intrinsic point defects in WSe2 monolayers revealed seven types of defects, with selenium mono-vacancy (V-Se) being the most dominant. The specific preparation method influences the exact content and diversity of point defects.
Article
Chemistry, Multidisciplinary
Hyoju Park, Gang Seob Jung, Khaled M. Ibrahim, Yang Lu, Kuo-Lun Tai, Matthew Coupin, Jamie H. Warner
Summary: This study investigates the atomic arrangements at the interfaces of mixed 2D heterostructures composed of Pd2Se3 and MoS2 semiconductors using atomic-resolution annular dark-field scanning transmission electron microscopy. The research finds that the similarity of geometry and the bonding between metal and chalcogen atoms are crucial factors in achieving lateral epitaxy. In addition, if the atomically stitched interface is of high quality and low defect density, the vertical van der Waal interactions can be overcome by in-plane forces.
Article
Materials Science, Multidisciplinary
Shuai Nan, Meng Xiao, Zhou Guan, Chuangshi Feng, Chao Huo, Gong Li, Pengfei Zhai, Fuxiang Zhang
Summary: Atomic-scale defects in ion irradiated 4H-SiC were identified using integrated differential phase contrast technique on aberration-corrected transmission electron microscopy and Raman scattering spectrometer. Si- and C-related vacancies and interstitials were imaged in 21 MeV Ni+ ions irradiated 4H-SiC, where electronic energy loss dominates the whole penetration depth. On the other hand, 900 keV Si+ ions produce more point defects, lattice distortions, and dislocations at the depth of damage peak. These point defects provide detailed information for the vibration modes in the Raman spectrum of damaged 4H-SiC. This study provides important fundamental information for nuclear and electronic applications.
MATERIALS CHARACTERIZATION
(2023)
Article
Chemistry, Multidisciplinary
Revannath Dnyandeo Nikam, Krishn Gopal Rajput, Hyunsang Hwang
Summary: The report introduces a quantized conductance atomic threshold switch (QCATS) using an atomically-thin hexagonal boron nitride (hBN) layer, which has applications in memory and logic devices. The device shows stable and reproducible conductance quantization state and operates by forming single-atom point contact through a monoatomic boron defect in the hBN layer. By implementing excellent switching characteristics with single-layer hBN, the possibility of stable and uniform atomic-switching devices for future memory and logic applications is confirmed.