Article
Physics, Applied
Sander Smink, Wilson Lin, Jochen Mannhart, Wolfgang Braun
Summary: We investigated the stoichiometry of a TiO2-rich SrTiO3(001) surface by depositing less than one monolayer of SrO. Our results show that this deposition leads to atomically flat islands on the step-and-terrace surface with a height of exactly one full SrTiO3 unit cell. The presence of a TiO2 double layer on the as-prepared SrTiO3(001) surface and the rearrangement of the top layer with deposited SrO are proposed to explain these findings.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Hojoon Lim, Chanyang Song, Minsik Seo, Dongwoo Kim, Moonjung Jung, Habin Kang, Seunghwan Kim, Kyung-Jae Lee, Youngseok Yu, Geonhwa Kim, Ki-Jeong Kim, Bongjin Simon Mun
Summary: Precise characterization of surface/interfacial properties of SrTiO3, a popular substrate for heterostructures, is crucial for understanding exotic physical phenomena related to electron/ion exchanges. Under different pressure conditions, the undoped SrTiO3 (001) surface forms different oxide structures, affecting its electronic properties and band bending.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Physical
Wenxuan Zhang, Xutao Wang, Ningning Liu, Jinyue Wang, Yueqiao Qu, Shiyong Wang, Hao Zheng, Yao-Yi Li, Canhua Liu, Jin-Feng Jia
Summary: Using scanning tunneling microscopy and spectroscopy, the molecular arrangement and electronic structure of C60 ultrathin films grown on a SrTiO3(0 0 1) surface were investigated. The monolayer C60 exhibited a short-range ordered molecular arrangement with disordered molecular orientation and a substantially large HOMO-LUMO gap (-4.1 eV). In contrast, C60 in the 2nd and 3rd layers self-assembled into hexagon lattices with a quasi-(2 x 2) superstructure, resulting in a chiral pinwheel structure.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Liangguang Jia, Fei Gao, Yu Zhang, Yaoyao Chen, Baofei Hou, Zeping Huang, Quanzhen Zhang, Xu Wu, Liwei Liu, Shiwu Gao, Mads Brandbyge, Hong-Jun Gao, Yeliang Wang
Summary: This study reports the influence of defects in vdW crystals on the local atomic configurations and interlayer coupling. The findings show that Se vacancies in few-layer NbSe2 can cause atomic distortions and generate in-gap states in single-layer NbSe2. Moreover, these vacancies lead to a significant suppression of interlayer coupling in the bilayer system.
Article
Physics, Condensed Matter
Mark J. Haastrup, Marco Bianchi, Lutz Lammich, Jeppe Lauritsen
Summary: In this study, an in-situ physical vapor deposition (PVD) method was used to investigate the structure and epitaxial alignment of single-layer MoS2 on SrTiO3 (STO) substrates. It was found that four distinct rotational domains of MoS2 formed on the STO(001) substrate, while only two formed on the STO(111) substrate. This methodology can be extended to other systems to explore pristine two-dimensional transition metal dichalcogenide/STO systems in general.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Physical
B. V. Andryushechkin, T. V. Pavlova, V. M. Shevlyuga
Summary: The atomic structure of the Ag(111)-p(4 x 4)-O phase was reexamined and two phases with the same periodicity were discovered. It was demonstrated that the accepted Ag6 model is incompatible with high-resolution oxygen-sensitive STM images.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Shigeru Kaku, Kota L. Hiwatari, Junji Yoshino
Summary: By optimizing the surface cleaning procedures and growth conditions, we investigated the surface structure of strained-alpha-Sn layers grown on InSb(001) surfaces, revealing that the (2 x 2) diffraction patterns are attributed to double domain (2 x 1) reconstructed surfaces rotated 90 degrees with respect to each other.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Analytical
Yufei Wang, Mingyang Li, Emma Gordon, Zhijiang Ye, Hang Ren
Summary: Understanding the structure-activity relationship in electrochemical metal dissolution reactions is crucial for designing higher density batteries and mitigating corrosions. The kinetics of metal dissolution is strongly influenced by surface structures, such as grain boundaries and defects. However, directly probing the electrochemical activity at these sites is challenging due to the limitation of conventional bulk electrochemistry. In this study, the colocalized mapping of an electrochemical metal dissolution reaction using Ag as a model system is reported. The local dissolution kinetics is measured using scanning electrochemical cell microscopy (SECCM) and correlated with the local structures obtained via colocalized electron backscattering diffraction (EBSD). The findings reveal the importance of nanoscale local electrochemical mapping and colocalized microscopic measurement in understanding the structure-activity relationship for electrochemical reactions at complex interfaces.
ANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Nicolas Neel, Joerg Kroeger
Summary: The study revealed that the formation of a chemical bond between a CO molecule and a Cu(111) surface is accompanied by bending of the molecular probe due to van der Waals attraction and Pauli repulsion, resulting in characteristic changes in the vertical force between CO and Cu(111) as a function of molecule-surface distance. Experimental data were successfully reproduced by model calculations, shedding new light on vertical-force extrema in scanning probe experiments.
Article
Chemistry, Multidisciplinary
Yuhiro Segawa, Kenji Yamazaki, Jun Yamasaki, Kazutoshi Gohara
Summary: A new method for measuring the 3D atomic structure of free-standing graphene ripples using TEM is proposed and experimentally validated. The specimen in the experiment was found to be moving upward, and the ripple was approximated as a composite of sinusoidal waves while measuring the time dependence of its height and lateral size.
Article
Chemistry, Multidisciplinary
Kaihui Li, Feiping Xiao, Wen Guan, Yulong Xiao, Chang Xu, Jinding Zhang, Chenfang Lin, Dong Li, Qingjun Tong, Si-Yu Li, Anlian Pan
Summary: Moire superlattices exhibit a magnification effect and are sensitive to both external disturbances and internal atomic reconstructions. Long-wavelength WS2 superlattices can be reconstructed into various moire morphologies, ranging from regular hexagons to heavily deformed shapes. The interaction between external nonuniform heterostrain and intrinsic atomic reconstruction is responsible for this interesting evolution of moire structures.
Article
Chemistry, Physical
Nyamaa Tsogtbaatar, Bolortsetseg Tuvdendorj, Altaibaatar Lkhagvasuren, Jae M. Seo, Myung-Whun Kim, Hidong Kim
Summary: The effect of Sn atoms on the C-incorporated Si(001)-4 degrees off surface was investigated. The deposition of 0.6-ML Sn atoms on the surface with subsurface C atoms resulted in a c(4x 4) reconstruction, where each Sn addimer bridges two Si dimers. This is in contrast to the c(8 x 4) reconstruction formed on the clean Si(001) terraces without subsurface C atoms, where Sn dimers replace Si dimers and every fourth dimer is vacant. The change in reconstruction is attributed to the smaller surface stress exerted by subsurface C atoms compared to Si atoms.
Article
Chemistry, Physical
Guan-Yu Chen, Chia-Hsiu Hsu, Bo-You Liu, Li-Wei Chang, Deng-Sung Lin, Feng-Chuan Chuang, Pin-Jui Hsu
Summary: The growth and quantum well electronic states of 2D Pb nanoislands on Nb-doped SrTiO3(001) were investigated using scanning tunneling microscopy and spectroscopy. Unlike other substrates, isolated Pb nanoislands with a height of 4 atomic layers were formed on the Nb-doped SrTiO3(001) surface as the building blocks for island growth. Energy-dependent scattering phase shift shows a metallic-like interface similar to Pb/Ag(1 1 1).
APPLIED SURFACE SCIENCE
(2021)
Review
Chemistry, Physical
Chunlei Yang, Tianhui Su, Yanbo Hua, Liming Zhang
Summary: This review summarizes the latest results of electrochemical scanning probe microscopy techniques in studying the interfacial properties of electrocatalysts and photoelectrodes, and offers some perspectives on future research directions.
Article
Optics
Raja S. R. Gajjela, Arthur L. Hendriks, James O. Douglas, Elisa M. Sala, Petr Steindl, Petr Klenovsky, Paul A. J. Bagot, Michael P. Moody, Dieter Bimberg, Paul M. Koenraad
Summary: By using X-STM and APT, the study of (InGa)(AsSb)/GaAs/GaP quantum dots grown by metal-organic vapor phase epitaxy revealed truncated pyramid shape structures with high GaAs content and lower In and Sb quantities. The composition of the QDs was estimated to be similar to InxGa1 - xAs1 - ySby, where x = 0.25-0.30 and y = 0.10-0.15, which was in agreement with experimental results.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Stuart R. Miller, Matthew S. J. Marshall, Megan Wart, Hassina Z. Bilheux, Louis J. Santodonato, Rick Riedel, Vivek V. Nagarkar
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2019)
Article
Engineering, Electrical & Electronic
Stuart R. Miller, Charles Brecher, Matthew S. J. Marshall, Megan Wart, Vivek V. Nagarkar
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2019)
Article
Engineering, Electrical & Electronic
Matthew S. J. Marshall, Peter Kenesei, Zsolt Marton, Charles Sosa, Charles Brecher, Megan Wart, Stuart Miller, Bipin Singh, Antonino Miceli, Vivek V. Nagarkar
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2020)
Article
Physics, Applied
Peiyu Chen, Yakun Gao, Martin R. Castell
APPLIED PHYSICS LETTERS
(2020)
Article
Engineering, Electrical & Electronic
Stuart R. Miller, Matthew S. J. Marshall, Megan Wart, Jan Crha, Pavel Trtik, Vivek V. Nagarkar
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2020)
Article
Chemistry, Physical
Yakun Gao, Peiyu Chen, Martin R. Castell
Summary: The study reveals the formation of a complex TiOx monolayer superstructure on palladium (Pd) crystal islands, consisting of two periodicities and requiring a formation area of at least 100 nm(2).
Article
Materials Science, Multidisciplinary
Peiyu Chen, Yakun Gao, Martin R. Castell
Summary: The SMSI process involves the encapsulation of metal particles by an oxide layer originating from the substrate, driven by a reduction in surface energy. Studies on epitaxial Pd nanocrystals grown on different substrates reveal that increasing crystal height results in a higher height-to-width ratio, but this increase is lower for encapsulated crystals due to modified interfacial structure during the SMSI process. The SMSI is preferentially observed on larger crystals, reducing the elastic strain energy and resulting in less strain in the encapsulated particles.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Shuqiu Wang, Xiao Hu, Jacek Goniakowski, Claudine Noguera, Martin R. Castell
Summary: Grain boundaries are important to understand polycrystalline materials and their properties. In 2D materials, grain boundaries can be described as line defects, and their atomic structures have been extensively studied. Zero-degree grain boundaries, called domain boundaries, where there is only a lattice offset between two grains without any rotation, are rare in 2D materials. By combining experimental and theoretical investigations, researchers observed and solved the atomic structures of four main domain boundaries in a monolayer of Ti2O3 supported on Au(111). The formation energies of these domain boundaries explain their different frequencies of occurrence. The strong epitaxial constraint from the Au(111) substrate stabilizes unique domain boundary structures that are not observed in van-der-Waals bonded 2D materials.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Analytical
Merel J. Lefferts, Martin R. Castell
Summary: Percolation networks of polypyrrole are used to detect buried ANFO in different types of soil, achieving reliable detection of low concentrations of ANFO, with clay acting as a significant barrier to NH3 permeability.
FORENSIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Merel J. Lefferts, Ben Armitage, Krishnan Murugappan, Martin R. Castell
Summary: This study demonstrates the use of PEDOT conducting polymer percolation networks for sensitive and reversible NO2 sensing. By adjusting the polymerization and doping conditions, control over sensing behavior is achieved, resulting in reversible NO2 sensors with higher sensitivity compared to traditional thin film sensors. A detection limit of 907 +/- 102 ppb was achieved.
Article
Chemistry, Analytical
Merel J. Lefferts, Lisa H. Humphreys, Nathalie Mai, Krishnan Murugappan, Ben Armitage, Jean-Francois Pons, Martin R. Castell
Summary: The development of ANFO vapour sensors for widespread IED detection faces challenges in achieving high sensitivity and low detection limits due to concealment and low vapour pressures. By using polymer percolation networks, ANFO chemiresistive vapour sensors show improved sensitivity compared to thin film sensors, detecting vapour concentrations emitted by various ammonium nitrate-containing fertilisers and fertiliser-diesel mixtures.
Article
Materials Science, Multidisciplinary
Nhlakanipho Mkhize, Krishnan Murugappan, Martin R. Castell, Harish Bhaskaran
Summary: Electrohydrodynamic Jet Printing (EHD) is capable of printing sub-micron structures with various materials, showing promising results in compared to traditional additive manufacturing techniques. By using EHD to print polyaniline-based chemiresistors, researchers achieved high detection sensitivity for ammonia gas sensors on both glass and flexible substrates. The study also highlighted the importance of dopant acids in polymer structure and sensing, paving the way for further development of miniaturized flexible polymer sensors.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Ben Armitage, Krishnan Murugappan, Merel J. Lefferts, Aditya Cowsik, Martin R. Castell
JOURNAL OF MATERIALS CHEMISTRY C
(2020)
Article
Energy & Fuels
Mauro Pasta, David Armstrong, Zachary L. Brown, Junfu Bu, Martin R. Castell, Peiyu Chen, Alan Cocks, Serena A. Corr, Edmund J. Cussen, Ed Darnbrough, Vikram Deshpande, Christopher Doerrer, Matthew S. Dyer, Hany El-Shinawi, Norman Fleck, Patrick Grant, Georgina L. Gregory, Chris Grovenor, Laurence J. Hardwick, John T. S. Irvine, Hyeon Jeong Lee, Guanchen Li, Emanuela Liberti, Innes McClelland, Charles Monroe, Peter D. Nellist, Paul R. Shearing, Elvis Shoko, Weixin Song, Dominic Spencer Jolly, Christopher Thomas, Stephen J. Turrell, Mihkel Vestli, Charlotte K. Williams, Yundong Zhou, Peter G. Bruce
JOURNAL OF PHYSICS-ENERGY
(2020)
Article
Chemistry, Physical
Peiyu Chen, Krishnan Murugappan, Martin R. Castell
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2020)
