Article
Physics, Multidisciplinary
Pampa Sadhukhan, Shuvam Sarkar, Sunil Wilfred D'Souza, Andrei Gloskovskii, Sudipta Roy Barman
Summary: The bulk electronic structure of Mn2NiGa in the austenite and martensite phases has been investigated using Hard X-ray Photoelectron Spectroscopy (HAXPES). In the austenite phase, a wide valence band (VB) spectrum with several prominent features has been observed, and theoretical calculations confirm that it is dominated by Ni 3d and Mn, Ni, Ga 4s states. Furthermore, the presence of anti-site disorder in Mn2NiGa has been established through the combination of experimental VB and Density Functional Theory (DFT) calculations. In the martensite phase, a marginal decrease in the density of states below the Fermi level and a slight shift in the main peak have been observed, which can be explained by the tetragonally distorted structure with anti-site disorder.
Article
Multidisciplinary Sciences
Jean-Baptiste Vaney, Baptiste Vignolle, Alain Demourgues, Etienne Gaudin, Etienne Durand, Christine Labrugere, Fabio Bernardini, Andres Cano, Sophie Tence
Summary: This article introduces a topochemical method for intercalating fluorine atoms into intermetallics and demonstrates its potential by synthesizing non-stoichiometric mixed anion LaFeSiFx single crystals, which exhibit FeSi-based superconductivity. The study shows that fluorine topochemistry on intermetallics is an effective route for providing functional materials.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Chao Yue Zhang, Xuan Lu, Xu Han, Jing Yu, Chaoqi Zhang, Chen Huang, Lluis Balcells, Alba Garzon Manjon, Jordi Jacas Biendicho, Junshan Li, Jordi Arbiol, Gengzhi Sun, Jin Yuan Zhou, Andreu Cabot
Summary: This study investigates the influence of the geometric configuration and composition of ABX spinel catalysts on their catalytic mechanisms and polysulfide conversion. The results show that Co-oh (3+) serves as the active site for breaking S-S bonds, while Co-td (2+) functions as the active site for forming S-Na bonds. This research highlights the subtle relationship between the activity and geometric configuration of spinel catalysts, offering insights for the rational development of improved catalysts by optimizing their atomic geometric configuration.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Hua Zhou, Hui-Qiong Wang, Jin-Cheng Zheng, Xiao-Dan Wang, Yufeng Zhang, Junyong Kang, Lihua Zhang, Kim Kisslinger, Rui Wu, Jia-Ou Wang, Hai-Jie Qian, Kurash Ibrahim
Summary: The electronic structure of the STO/ZnO heterointerface was investigated using in situ photoemission spectroscopy and X-ray absorption spectroscopy, revealing the formation of polar interfaces and electron transfer phenomena.
RESULTS IN PHYSICS
(2021)
Article
Materials Science, Ceramics
Komal K. Jani, Pooja Y. Raval, Nimish H. Vasoya, Monika Nehra, Mamraj Singh, Narendra Jakhar, Sandeep Kumar, Kunal B. Modi, Dong-Kwon Lim, Rishi Kumar Singhal
Summary: X-ray photoelectron spectroscopy (XPS) was used to investigate the electronic structure of Zn0.3Mn0.7+xSixFe2-2xO4 ferrite series. The results revealed the presence of Si ions in the +4 valence state. Silicon-oxygen (Si-O) and suboxide SiOx were found to be present in the system, with an increase in Si-O content and a decrease in SiOx content upon Mn-Si substitution. The Fe2p XPS spectra indicated the co-occurrence of ferrous and ferric ions in the system, with ferrous ions occupying octahedral sites and ferric ions dwelling on both octahedral and tetrahedral sites. The O1s spectra showed an increase in oxygen defects with increasing Mn-Si substitution. The Mn2p XPS data showed an overall increasing trend in the Mn+2 states and an increment in the Mn+4/Mn+3 ratio with increasing Mn-Si substitution.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Multidisciplinary
Ziyi Chen, Andrew G. Walsh, Xiao Wei, Manzhou Zhu, Peng Zhang
Summary: This study investigates the electronic properties of Ag-25(SR)(18) and Au-25(SR)(18) and develops a unique method to analyze the charge transfer behavior of nanoclusters. Experimental X-ray spectroscopy is used to demonstrate the bonding properties of silver nanoclusters, with the staple motif shown to have a significant impact on their electronic properties. The effective X-ray analysis techniques developed here provide new opportunities for the site-specific study of other nanoclusters.
Review
Physics, Condensed Matter
Curran Kalha, Nathalie K. Fernando, Prajna Bhatt, Fredrik O. L. Johansson, Andreas Lindblad, Hakan Rensmo, Leon Zendejas Medina, Rebecka Lindblad, Sebastian Siol, Lars P. H. Jeurgens, Claudia Cancellieri, Kai Rossnagel, Katerina Medjanik, Gerd Schonhense, Marc Simon, Alexander X. Gray, Slavomir Nemsak, Patrick Loemker, Christoph Schlueter, Anna Regoutz
Summary: Hard x-ray photoelectron spectroscopy (HAXPES) is a crucial technique for material characterization, with a growing number of specialized techniques utilizing hard x-rays to provide transformative insights into the nature of materials. This paper offers a historical perspective on HAXPES, from its early developments to state-of-the-art instrumentation, and aims to provide an overview of the technique in 2020 and potential future developments.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Multidisciplinary
Giovanni Chemello, Xenia Knigge, Dmitri Ciornii, Benjamen P. Reed, Andrew J. Pollard, Charles A. Clifford, Tom Howe, Neil Vyas, Vasile-Dan Hodoroaba, Joerg Radnik
Summary: The influence of the morphology of graphene particles on XPS results was studied. It was found that the size of the particles affects the degree of functionalization, and only the combination of XPS and HAXPES allows detection of the functionalization process and provides new insights.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Jumpei Yamada, Ichiro Inoue, Taito Osaka, Takato Inoue, Satoshi Matsuyama, Kazuto Yamauchi, Makina Yabashi
Summary: X-ray scientists are working to improve the quality of X-ray microscopy by proposing an innovative method for constructing an SXM equipped with a nanoprobe scanner, achieving single-nanometre accuracy in X-ray probe scanning. This method has been verified to be effective for achieving high resolution imaging with X-ray microscopy.
Article
Chemistry, Physical
Pramod Vishwakarma, Maheswar Nayak, V. R. Reddy, Andrei Gloskovskii, Wolfgang Drube, Ajay Gupta
Summary: The characteristics of the interfaces in the magnetic layer of the heterostructure Ta/Co2FeAl/MgO have been studied using HAXPES. It has been observed that the behavior of Co and Fe at the interfaces is different, with a higher percentage of Fe being oxidized or alloyed. The oxidation state of both Co and Fe decreases as the distance from the MgO interface increases, and Fe is further oxidized and Co is partially reduced after thermal annealing.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Applied
M. A. Khaled, D. C. Arnold, B. Dkhil, M. Jouiad, K. Hoummada, M. El Marssi, H. Bouyanfif
Summary: The use of nanoscale superlattices to design new anti-ferroelectric systems is an elegant strategy in the pursuit of high energy density capacitors. In-depth characterization of BiFeO3/NdFeO3 superlattices reveals that the stability of the anti-polar state within the superlattices is controlled by the thickness of the BiFeO3 layer and interlayer strain.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Hongchang Wang, Kawal Sawhney
Summary: Researchers have successfully generated omnidirectional differential phase images using X-ray differential phase contrast imaging, providing more information for studying complex samples and enabling simultaneous extraction of omnidirectional dark-field images to study ordered scattering structures.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Multidisciplinary Sciences
Hongchang Wang, Kawal Sawhney
Summary: This article introduces a method for generating omnidirectional differential phase images by scanning a randomly structured modulator, which provides more information than traditional imaging methods and allows the simultaneous extraction of omnidirectional dark-field images for studying strongly ordered scattering structures.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Applied
S. Magalhaes, M. Dias, B. Nunes, F. Oliveira, M. F. Cerqueira, E. Alves
Summary: This study presents a comprehensive and systematic study challenging the application of Vegard's rule to germanium tin solid solutions grown on different substrates. The results suggest that the germanium tin solid solutions follow Vegard's rule in the range of low tin molar fractions. Additionally, surface morphology issues were also observed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Makoto Takayanagi, Takashi Tsuchiya, Shigenori Ueda, Tohru Higuchi, Kazuya Terabe
Summary: The combination of in situ HAXPES and electrochemical measurements allows for the separation and quantitative evaluation of reversible Li+, irreversible Li2WO4 formation, and irreversible Li+ trapping. The inserted Li+ conversion ratios of reversible Li+, irreversible Li2WO4 formation, and irreversible Li+ trapping were clarified to be 41.4%, 50.9%, and 7.7%, respectively.
APPLIED SURFACE SCIENCE
(2021)
Article
Engineering, Electrical & Electronic
Jiangwei Liu, Hirotaka Ohsato, Bo Da, Yasuo Koide
Summary: The ohmic contact resistance, surface resistance, and channel resistance of H-terminated diamond MOSFETs were investigated. It was found that the surface resistance accounts for 75.3% of the total resistance in the planar-type H-diamond MOSFET, limiting its leakage current and extrinsic transconductance, while the ohmic contact resistance occupies 38.8% of the total resistance in the T-type H-diamond MOSFET.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Physics, Applied
Masaya Morita, Keiji Ishibashi, Kenichiro Takahashi, Shigenori Ueda, Jun Chen, Kota Tatejima, Toyohiro Chikyow, Atsushi Ogura, Takahiro Nagata
Summary: The effects of reactive gas flow conditions on the growth of nonpolar AlN films were investigated. It was found that low-temperature growth prevents unintentional nitridation and results in the crystallization of nonpolar AlN. Additionally, an appropriate N-2 flow improves the crystallinity and reduces defects, suppressing reactions at the interface.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Alexandra Papadogianni, Takahiro Nagata, Oliver Bierwagen
Summary: The alloying of In2O3 and Ga2O3 can modulate the properties of the parent compounds, such as the character of oxygen vacancies and the presence of a surface electron accumulation layer. The addition of Ga increases the electron density due to native defects, possibly caused by Ga-related unit-cell distortions. X-ray photoelectron spectroscopy measurements confirm the existence of a surface electron accumulation layer in all alloy films, and Hall and Seebeck measurements show negligible contribution of the surface electron accumulation layer to electron transport.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Huanying Sun, Liwen Sang, Xiulin Shen, Xuelin Yang, Tiefu Li, J. Q. You, Bo Shen, Meiyong Liao
Summary: This study demonstrates that highly stressed GaN on Si nanomechanical resonators exhibit high quality factor and low temperature coefficient of resonance frequency at elevated temperatures. This is achieved through the high stress and geometrical nonlinearity of dynamical strain in the GaN resonator, which compensates for the dissipation caused by the change of material properties with increasing temperature.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Takehiro Shimaoka, Meiyong Liao, Satoshi Koizumi
Summary: In this study, a phosphorus-doped n-type diamond MESFET device was developed, demonstrating clear pinch-off and saturation characteristics. The transconductance was significantly improved from room temperature to 300 degrees C.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Alexandra Papadogianni, Charlotte Wouters, Robert Schewski, Johannes Feldl, Jonas Lahnemann, Takahiro Nagata, Elias Kluth, Martin Feneberg, Rudiger Goldhahn, Manfred Ramsteiner, Martin Albrecht, Oliver Bierwagen
Summary: In this study, single-crystalline bixbyite (In1-xGax)(2)O-3 films were grown on (111)-oriented yttria-stabilized zirconia substrates using plasma-assisted molecular beam epitaxy. The addition of a pure In2O3 buffer layer between the substrate and (In1-xGax)(2)O-3 alloy improved the film surface smoothness and crystallinity. The distribution of Ga cations in the films was found to be non-uniform, with high Ga density inclusions observed at higher Ga content. The cubic bixbyite phase was preserved in both the matrix and the inclusions.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Ibrahima Gueye, Riku Kobayashi, Shigenori Ueda, Toshihide Nabatame, Kazuhito Tsukagoshi, Atsushi Ogura, Takahiro Nagata
Summary: The authors used operando-HAXPES with synchrotron radiation source to investigate the Au/InO1.16C0.04/Al2O3/p(+)-Si structure under bias voltage. They found that the InO1.16C0.04 layer removes oxygen from the Al2O3 layer and creates an oxygen depletion region in the Al2O3 film. The redox process mainly occurs near the Au/InO1.16C0.04 top interface.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Takahiro Nagata, Yuya Suemoto, Yoshihiro Ueoka, Masami Mesuda, Liwen Sang, Toyohiro Chikyow
Summary: The ability to control the polarity of an all-sputtered epitaxial GaN/AlN/Al film on a Si(111) substrate via intermediate oxidization was investigated. The results showed that by intentionally oxidizing the AlN layer, the polarity of the GaN surface can be changed from N-terminated to Ga-terminated. However, this intentional oxidation process may degrade the crystallinity of the GaN/AlN layer, which can be recovered through adjusting the oxidation point and repeating the growth process.
Article
Chemistry, Physical
Zilong Zhang, Liwen Sang, Jian Huang, Linjun Wang, Yasuo Koide, Satoshi Koizumi, Meiyong Liao
Summary: The authors report the enhancement of magnetic sensitivity in a single-crystal diamond MEMS magnetic sensor by incorporating different interlayers between the diamond cantilever and the magnetostrictive Galfenol thin film. These interlayers greatly improve the thermal stability, phase structures, and magnetic properties of the FeGa thin film, leading to enhanced magnetic performance under high temperatures. The FeGa/WC/Ti/SCD structure exhibits the highest magnetic sensitivity among the tested structures. Overall, this work provides insights into tailoring the magnetic sensing properties of SCD MEMS for extreme conditions.
Article
Chemistry, Multidisciplinary
Zilong Zhang, Wen Zhao, Guo Chen, Masaya Toda, Satoshi Koizumi, Yasuo Koide, Meiyong Liao
Summary: This study demonstrates an integrated on-chip single-crystal diamond (SCD) micro-electromechanical system (MEMS) magnetic transducer at high temperatures by coupling SCD with a large magnetostrictive FeGa film. The FeGa film is multifunctionalized to actuate the resonator, self-sense the external magnetic field, and electrically readout the resonance signal. The on-chip SCD MEMS transducer shows high sensitivity and low noise levels, providing a basis for the development of magnetic image sensors.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jiangwei Liu, Masayuki Okamura, Hisanori Mashiko, Masataka Imura, Meiyong Liao, Ryosuke Kikuchi, Michio Suzuka, Yasuo Koide
Summary: Super-high dielectric constant (k) AlOx/TiOy nanolaminates (ATO NLs) are deposited through atomic layer deposition technique for application in next-generation electronics. The shape of the Raman spectrum tends to resemble that of a single AlOx layer as AlOx content increases in each ATO sublayer. The deposition conditions of ATO NLs have significant effects on the electrical properties of metal/ATO NL/metal capacitors.
Article
Multidisciplinary Sciences
Liwen Sang, Meiyong Liao, Masatomo Sumiya, Xuelin Yang, Bo Shen
Summary: We grew InGaN films with a thickness of 0.3-1 μm using a specially designed high-pressure MOCVD method at pressures up to 2.5 atm. The high-pressure MOCVD method enhanced In incorporation and inhibited phase separations, resulting in improved crystalline quality and surface morphologies, especially for In-rich InGaN. We further demonstrated In0.4Ga0.6N with a thickness of 300 nm as the active region of solar cells, achieving a wide photoresponse range from ultraviolet to more than 750 nm.
FUNDAMENTAL RESEARCH
(2023)
Review
Quantum Science & Technology
Huanying Sun, Zilong Zhang, Yulong Liu, Guo Chen, Tiefu Li, Meiyong Liao
Summary: This paper reviews the development of diamond-based micro/nanoelectromechanical systems (MEMS/NEMS) from classic devices to quantum systems. The fabrication process and classic applications of diamond MEMS/NEMS devices are first described. Then, the physical properties of nitrogen-vacancy defect center, as well as their application in hybrid systems with MEMS structures, strain-spin interaction, and diamond-based optomechanics are introduced. It is expected that diamond MEMS/NEMS will play a significant role in both high-performance classic MEMS devices and quantum sensing/information research.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
Keyun Gu, Zilong Zhang, Haofei Huang, Ke Tang, Jian Huang, Meiyong Liao, Linjun Wang
Summary: Self-powered solar-blind UV detectors with asymmetric electrode structures have been developed for a-Ga2O3 photodetectors, showing high responsivity, external quantum efficiency and detectivity. These detectors have different Schottky barrier heights in the electrode-film interfaces, enabling self-powered performance. They have fast photo-response speed, high stability and repeatability, providing a promising and facile route for high photodetection in a-Ga2O3 self-powered solar-blind UV detectors.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Correction
Engineering, Electrical & Electronic
Jingmin Tang, Soichiro Takeuchi, Masaki Tanaka, Hiroto Tomita, Yusuke Hashimoto, Takahiro Nagata, Jun Chen, Takuo Ohkochi, Yoshinori Kotani, Tomohiro Matsushita, Yoshiyuki Yamashita
ACS APPLIED ELECTRONIC MATERIALS
(2022)