Article
Chemistry, Multidisciplinary
Bingyao Liu, Qi Chen, Zhaolong Chen, Shenyuan Yang, Jingyuan Shan, Zhetong Liu, Yue Yin, Fang Ren, Shuo Zhang, Rong Wang, Mei Wu, Rui Hou, Tongbo Wei, Junxi Wang, Jingyu Sun, Jinmin Li, Zhongfan Liu, Zhiqiang Liu, Peng Gao
Summary: This study demonstrates the successful fabrication of low-strain single-crystalline nitride films on highly mismatched substrates via graphene-assisted remote heteroepitaxy. By weakening the interface potential and smoothing the atomic steps with graphene, the dislocation density caused by lattice mismatches is significantly reduced, leading to the fabrication of a yellow light-emitting diode.
Article
Physics, Applied
Sevil Sarikurt, Yusuf Zuntu Abdullahi, Engin Durgun, Fatih Ersan
Summary: This study investigates the thermal expansion coefficients of group III-Nitride monolayers with temperature, revealing high negative values below room temperature and a convergence to zero for certain monolayers above room temperature. The highest contribution to negative thermal expansion comes from the ZA phonon mode. These findings are important for the design of nanoscale heat devices.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Manali Nandy, Agnieszka Paszuk, Markus Feifel, Christian Koppka, Peter Kleinschmidt, Frank Dimroth, Thomas Hannappel
Summary: The study demonstrates the use of high-quality virtual substrates, such as GaP/AlP pulsed nucleation layers, to improve the crystalline quality and reduce crystal defects in III-V multilayer structures grown on Si(100) wafers, ultimately enhancing device performance.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Multidisciplinary Sciences
Xuexi Yan, Yixiao Jiang, Qianqian Jin, Tingting Yao, Weizhen Wang, Ang Tao, Chunyang Gao, Xiang Li, Chunlin Chen, Hengqiang Ye, Xiu-Liang Ma
Summary: By combining transmission electron microscopy, first-principles calculations, and cathodoluminescence spectroscopy, we demonstrate unexpected strong interfacial interactions at the incoherent AlN/Al2O3 (0001) interface with a large mismatch, which result in the formation of misfit dislocation networks and stacking faults rarely observed at other incoherent interfaces. The strong interfacial interactions significantly tailor the interfacial atomic structure and electronic properties, leading to a reduced band gap and strong interfacial ultraviolet light emission. These findings suggest the potential of incoherent interfaces in developing novel heterojunction materials and devices.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Hesham El-Sherif, Natalie Briggs, Brian Bersch, Minghao Pan, Mahdi Hamidinejad, Siavash Rajabpour, Tobin Filleter, Ki Wook Kim, Joshua Robinson, Nabil D. Bassim
Summary: In this study, the thickness of 2D-Ga heterostructures was resolved and measured using scanning electron microscopy (SEM), with the SEM image contrast directly related to the presence of uniform bilayer Ga at the interface and variation of graphene layers. By utilizing multiple correlative methods, the researchers investigated the origin of SEM contrast and found that a carbon buffer layer detached due to gallium intercalation, increasing the surface potential as an indication of the 2D-Ga presence. The study also successfully scaled up heterostructure characterization over a few-square millimeter area by segmenting SEM images with nanometer-scale in-plane resolution, leveraging the spectroscopic imaging capabilities of SEM for tracking intercalants, identifying relative surface potentials, determining the number of 2D layers, and further characterizing scalability and uniformity of low-dimensional materials.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Bruno Daudin, Alexandra-Madalina Siladie, Marion Gruart, Martien den Hertog, Catherine Bougerol, Benedikt Haas, Jean-Luc Rouviere, Eric Robin, Maria-Jose Recio-Carretero, Nuria Garro, Ana Cros
Summary: The spontaneous growth of GaN nanowires in the absence of catalyst is controlled by Ga flux, with diffusion barriers causing an uneven distribution of Ga adatoms at the top surface leading to GaN accumulation in the periphery. This promotes the formation of superlattices in InGaN and AlGaN nanowires, while the presence of Mg enhances Al diffusion length along the sidewalls in AlN nanowires, inducing the formation of AlN nanotubes.
Article
Materials Science, Ceramics
Lingfeng He, Tiankai Yao, Kaustubh Bawane, Miaomiao Jin, Chao Jiang, Xiang Liu, Wei-Ying Chen, J. Matthew Mann, David H. Hurley, Jian Gan, Marat Khafizov
Summary: The early stage of microstructural evolution of ThO2 under krypton irradiation was studied using in situ transmission electron microscopy (TEM). The growth rate and density of dislocation loops were investigated with changing irradiation temperature and ion dose. Different types of dislocation loops were determined using various TEM techniques, and diffusion coefficients of different defects were extracted using a rate theory model.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Review
Physics, Multidisciplinary
Wenliang Wang, Hongsheng Jiang, Linhao Li, Guoqiang Li
Summary: This review focuses on the theoretical and experimental studies on 2D group-III nitride materials and devices, outlining various properties determined using simulations and theoretical calculations, breakthroughs in synthesis methods, and discussions on devices. The review also speculates on the prospect for the further development of 2D group-III nitride materials and devices based on recent progress.
REPORTS ON PROGRESS IN PHYSICS
(2021)
Article
Agricultural Engineering
L. Kozlova, A. Petrova, A. Chernyad'ev, V Salnikov, T. Gorshkova
Summary: Quantitative estimation of dislocations in flax bast fibers revealed that defects mainly occur during scutching, with no dislocations found in fibers within the stem. This suggests that disruption of flax stem integrity and mechanical treatments are the main factors in fiber deformation.
INDUSTRIAL CROPS AND PRODUCTS
(2022)
Article
Chemistry, Physical
Ning Wang, Peng Wang, Fengzhi Wang, Haiping He, Jinyun Huang, Xinhua Pan, Guangming Zhu, Jiangbo Wang, Zhizhen Ye
Summary: This study investigates the growth of ZnO film on a graphene-buffered sapphire substrate using plasma-assisted molecular beam epitaxy (PAMBE). The results show that the crystal quality of ZnO film can be improved by buffering it with double-layer graphene (DLG), leading to the formation of symmetric pits on the film surface. The findings have implications for the development of simplified growth technology for ZnO-based films and devices.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Junyang An, Jean-Luc Maurice, Valerie Depauw, Pere Roca i Cabarrocas, Wanghua Chen
Summary: This study explores the impact of two plasma-based surface engineering methods on the crystalline quality of epitaxial Si layers grown at different temperatures. It was found that the addition of a SiGe heteroepitaxial layer resulted in higher interfacial hydrogen content and better overall epitaxial Si quality compared to using a homoepitaxial Si layer at the interface.
APPLIED SURFACE SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
L. Jaloustre, S. Le Denmat, T. Auzelle, M. Azadmand, L. Geelhaar, F. Dahlem, R. Songmuang
Summary: This study demonstrates semi-quantitative PFM can be achieved on low piezocoefficient III-nitrides in high-aspect-ratio nanostructures, and improved electric field distribution in nanowires minimizes measurement artifacts. Contrary to previous reports, giant piezoelectricity was not observed in III-N nanowires with diameters ranging from 30-80 nm.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Qi Chen, Kailai Yang, Bo Shi, Xiaoyan Yi, Junxi Wang, Jinmin Li, Zhiqiang Liu
Summary: Beyond traditional heteroepitaxy, 2D-materials-assisted epitaxy opens opportunities to revolutionize future material integration methods. However, basic principles in 2D-material-assisted nitrides' epitaxy remain unclear, which impedes understanding the essence, thus hindering its progress. Here, the crystallographic information of nitrides/2D material interface is theoretically established, which is further confirmed experimentally. It is found that the atomic interaction at the nitrides/2D material interface is related to the nature of underlying substrates. For single-crystalline substrates, the heterointerface behaves like a covalent one and the epilayer inherits the substrate's lattice. Meanwhile, for amorphous substrates, the heterointerface tends to be a van der Waals one and strongly relies on the properties of 2D materials. Therefore, modulated by graphene, the nitrides' epilayer is polycrystalline. In contrast, single-crystalline GaN films are successfully achieved on WS2. These results provide a suitable growth-front construction strategy for high-quality 2D-material-assisted nitrides' epitaxy. It also opens a pathway toward various semiconductors heterointegration.
ADVANCED MATERIALS
(2023)
Article
Engineering, Mechanical
Zhihong Wu, Hongchao Kou, Jinshan Li, Samuel Hemery, Nana Chen, Junhui Tang, Fengming Qiang, Fan Sun, Frederic Prima
Summary: Dwell fatigue failure of titanium alloy components has been a major threat to aircraft safety for the past 50 years. Designing a microstructure with low primary alpha phase content can achieve high strength and low sensitivity to dwell loading. Cracking occurs primarily along preexisting slip bands and twist grain boundaries. Load holding plays a significant role in crack initiation and switching of crack modes.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Daniel Kiener, Amit Misra
Summary: This article provides an overview of recent developments in test methodologies for nanoindenter-based small-length-scale mechanical characterization. It emphasizes the possibilities offered by in situ testing in transmission and scanning electron microscopes, as well as the examination of strain rate and temperature dependence of mechanical strength. The versatility and growing impact of new nanomechanical characterization tools are highlighted through selected recent examples.
Article
Physics, Applied
Sean W. King, Robert J. Nemanich, Robert F. Davis
JOURNAL OF APPLIED PHYSICS
(2015)
Article
Materials Science, Coatings & Films
Sean W. King, Robert F. Davis, Richard J. Carter, Thomas P. Schneider, Robert J. Nemanich
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2015)
Article
Materials Science, Coatings & Films
Sean W. King, Satoru Tanaka, Robert F. Davis, Robert J. Nemanich
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2015)
Article
Materials Science, Multidisciplinary
Robert F. Davis
Article
Chemistry, Physical
Sean W. King, Robert J. Nemanich, Robert F. Davis
SURFACE AND INTERFACE ANALYSIS
(2015)
Article
Materials Science, Coatings & Films
Fang Liu, Li Huang, Lisa M. Porter, Robert F. Davis, Daniel K. Schreiber
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2016)
Article
Multidisciplinary Sciences
Michael Schmitt, Jianan Zhang, Jaejun Lee, Bongjoon Lee, Xin Ning, Ren Zhang, Alamgir Karim, Robert F. Davis, Krzysztof Matyjaszewski, Michael R. Bockstaller
Article
Materials Science, Coatings & Films
Sean W. King, Robert F. Davis, Robert J. Nemanich
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2014)
Article
Materials Science, Coatings & Films
Sean W. King, Robert F. Davis, Robert J. Nemanich
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2014)
Article
Physics, Condensed Matter
Sean W. King, Robert J. Nemanich, Robert F. Davis
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2015)
Article
Engineering, Electrical & Electronic
Krishna Shenai, Michael Dudley, Robert F. Davis
PROCEEDINGS OF THE IEEE
(2014)
Article
Materials Science, Coatings & Films
Philip M. Jean-Remy, Matthew J. Cabral, Robert F. Davis
Summary: Nanocrystalline sp(2)-BN thin films were successfully grown on SiC substrates via continuous flow and discontinuous flow-modulated chemical vapor deposition techniques. Stoichiometric BN was achieved in continuously grown films within a certain gas phase ratio range, while minimization of B2H6 flow rate and injection time was required for discontinuously grown films. Short injection times relative to NH3 resulted in partially ordered sp(2)-BN layers, whereas long injection times led to mixtures of amorphous and sp(2)-BN without any observed ordering.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Materials Science, Coatings & Films
Philip M. Jean-Remy, Matthew J. Cabral, Robert F. Davis
Summary: Nanocrystalline sp(2)-boron nitride (BN) thin films were grown on mechanically polished polycrystalline pyrolytic boron nitride substrates via chemical vapor deposition. The films exhibited a stoichiometric surface chemistry and an increase in roughness with growth time and thickness.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Proceedings Paper
Electrochemistry
Y. Yao, L. A. M. Lyle, J. A. Rokholt, S. Okur, G. S. Tompa, T. Salagaj, N. Sbrockey, R. F. Davis, L. M. Porter
GALLIUM NITRIDE AND SILICON CARBIDE POWER TECHNOLOGIES 7
(2017)
Article
Materials Science, Multidisciplinary
Justin P. Freedman, Xiaoxiao Yu, Robert F. Davis, Andrew J. Gellman, Jonathan A. Malen
Article
Materials Science, Multidisciplinary
Y. Liu, K. Zweiacker, C. Liu, J. T. McKeown, J. M. K. Wiezorek
Summary: The evolution of rapid solidification microstructure and solidification interface velocity of hypereutectic Al-20at.%Cu alloy after laser melting has been studied experimentally. It was found that the formation of microstructure was dominated by eutectic, alpha-cell, and banded morphology grains, and the growth modes changed with increasing interface velocity.
Article
Materials Science, Multidisciplinary
Bharat Gwalani, Julian Escobar, Miao Song, Jonova Thomas, Joshua Silverstein, Andrew Chihpin Chuang, Dileep Singh, Michael P. Brady, Yukinori Yamamoto, Thomas R. Watkins, Arun Devaraj
Summary: Castable alumina forming austenitic alloys exhibit superior creep life and oxidation resistance at high temperatures. This study reveals the mechanism behind the enhanced creep performance of these alloys by suppressing primary carbide formation and offers a promising alloy design strategy for high-temperature applications.
Article
Materials Science, Multidisciplinary
Jian Song, Qi Zhang, Songsong Yao, Kunming Yang, Houyu Ma, Jiamiao Ni, Boan Zhong, Yue Liu, Jian Wang, Tongxiang Fan
Summary: Recent studies have shown that achieving an atomically flat surface for metals can greatly improve their oxidation resistance and enhance their electronic-optical applications. Researchers have explored the use of graphene as a covering layer to achieve atomically flat surfaces. They found that high-temperature deposited graphene on copper surfaces formed mono-atomic steps, while annealed copper and transferred graphene on copper interfaces formed multi-atomic steps.
Article
Materials Science, Multidisciplinary
Jennifer A. Glerum, Jon-Erik Mogonye, David C. Dunand
Summary: Elemental powders of Al, Ti, Sc, and Zr are blended and processed via laser powder-bed fusion to create binary and ternary alloys. The microstructural analysis and mechanical testing show that the addition of Ti results in the formation of primary precipitates, while the addition of Sc and Zr leads to the formation of fine grain bands. The Al-0.25Ti-0.25Zr alloy exhibits comparable strain rates to Al-0.5Zr at low stresses, but significantly higher strain rates at higher stresses during compressive creep testing. Finite element modeling suggests that the connectivity of coarse and fine grain regions is a critical factor affecting the creep resistance of the alloys.
Article
Materials Science, Multidisciplinary
P. Jannotti, B. C. Hornbuckle, J. T. Lloyd, N. Lorenzo, M. Aniska, T. L. Luckenbaugh, A. J. Roberts, A. Giri, K. A. Darling
Summary: This work characterizes the thermo-mechanical behavior of bulk nanocrystalline Cu-Ta alloys under extreme conditions. The experiments reveal that the alloys exhibit unique mechanical properties, behaving differently from conventional nanocrystalline Cu. They do not undergo grain coarsening during extrusion and exhibit behavior similar to coarse-grained Cu.
Article
Materials Science, Multidisciplinary
Yiqing Wei, Jingwei Li, Daliang Zhang, Bin Zhang, Zizhen Zhou, Guang Han, Guoyu Wang, Carmelo Prestipino, Pierric Lemoine, Emmanuel Guilmeau, Xu Lu, Xiaoyuan Zhou
Summary: This study proposes a new strategy to modify microstructure by phase regulation, which can simultaneously enhance carrier mobility and reduce lattice thermal conductivity. The addition of Cu in layered SnSe2 induces a phase transition that leads to increased grain size and reduced stacking fault density, resulting in improved carrier mobility and lower lattice thermal conductivity.
Article
Materials Science, Multidisciplinary
Jia Chen, Zhengyu Zhang, Eitan Hershkovitz, Jonathan Poplawsky, Raja Shekar Bhupal Dandu, Chang-Yu Hung, Wenbo Wang, Yi Yao, Lin Li, Hongliang Xin, Honggyu Kim, Wenjun Cai
Summary: In this study, the structural origin of the pH-dependent repassivation mechanisms in multi-principal element alloys (MPEA) was investigated using surface characterization and computational simulations. It was found that selective oxidation in acidic to neutral solutions leads to enhanced nickel enrichment on the surface, resulting in reduced repassivation capability and corrosion resistance.
Article
Materials Science, Multidisciplinary
X. Y. Xu, C. P. Huang, H. Y. Wang, Y. Z. Li, M. X. Huang
Summary: The limited slip systems of magnesium (Mg) and its alloys hinder their wide applications. By conducting tensile straining experiments, researchers discovered a rate-dependent transition in the dislocation mechanisms of Mg alloys. At high strain rates, glissile dislocations dominate, while easy-glide dislocations dominate at low strain rates. Abundant glissile dislocations do not necessarily improve ductility.
Article
Materials Science, Multidisciplinary
M. S. Szczerba, M. J. Szczerba
Summary: Inverse temperature dependences of the detwinning stress were observed in face-centered cubic deformation twins in Cu-8at.%Al alloy. The detwinning stress increased with temperature when the pi detwinning mode was involved, but decreased when the pi/3 mode was involved. The dual effect of temperature on the detwinning stress was due to the reduction of internal stresses pre-existing within the deformation twins. The complete reduction of internal stresses at about 530 degrees C led to the equivalence of the critical stresses of different detwinning modes and a decrease in the yield stress anisotropy of the twin/matrix structure.
Article
Materials Science, Multidisciplinary
Taowen Dong, Tingting Qin, Wei Zhang, Yaowen Zhang, Zhuoran Feng, Yuxiang Gao, Zhongyu Pan, Zixiang Xia, Yan Wang, Chunming Yang, Peng Wang, Weitao Zheng
Summary: The interaction between the electrode and the electric double layer (EDL) significantly influences the energy storage mechanism. By studying the popular alpha-Fe2O3 electrode and the EDL interaction, we find that the energy storage mechanism of the electrode can be controlled by modulating the EDL.
Article
Materials Science, Multidisciplinary
Matthew R. Barnett, Jun Wang, Sitarama R. Kada, Alban de Vaucorbeil, Andrew Stevenson, Marc Fivel, Peter A. Lynch
Summary: The elastic-plastic transition in magnesium alloy Mg-4.5Zn exhibits bursts of deformation, which are characterized by sudden changes in grain orientation. These bursts occur in a coordinated manner among nearby grains, with the highest burst rate observed at the onset of full plasticity. The most significant burst events are associated with twinning, supported by the observation of twinned structures using electron microscopy. The bursts are often preceded and followed by a stasis in peak movement, indicating a certain "birth size" for twins upon formation and subsequent growth at a later stage.
Article
Materials Science, Multidisciplinary
Vaidehi Menon, Sambit Das, Vikram Gavini, Liang Qi
Summary: Understanding solute segregation thermodynamics is crucial for investigating grain boundary properties. The spectral approach and thermodynamic integration methods can be used to predict solute segregation behavior at grain boundaries and compare with experimental observations, thus aiding in alloy design and performance control.
Article
Materials Science, Multidisciplinary
Feiyu Qin, Lei Hu, Yingcai Zhu, Yuki Sakai, Shogo Kawaguchi, Akihiko Machida, Tetsu Watanuki, Yue-Wen Fang, Jun Sun, Xiangdong Ding, Masaki Azuma
Summary: This study reports on the negative and zero thermal expansion properties of Cd2Re2O7 and Cd1.95Ni0.05Re2O7 materials, along with their ultra-low thermal conductivity. Through investigations of their structures and phonon calculations, the synergistic effect of local structure distortion and soft phonons is revealed as the key to achieving these distinctive properties.
Article
Materials Science, Multidisciplinary
Thomas Beerli, Christian C. Roth, Dirk Mohr
Summary: A novel testing system for miniature specimens is designed to characterize the plastic response of materials for which conventional full-size specimens cannot be extracted. The system has an automated operation process, which reduces the damage to specimens caused by manual handling and improves the stability of the test results. The experiments show that the miniature specimens extracted from stainless steel and aluminum have high reproducibility, and the results are consistent with those of conventional-sized specimens. A correction procedure is provided to consider the influence of surface roughness and heat-affected zone caused by wire EDM.
Article
Materials Science, Multidisciplinary
Rani Mary Joy, Paulius Pobedinskas, Nina Baule, Shengyuan Bai, Daen Jannis, Nicolas Gauquelin, Marie-Amandine Pinault-Thaury, Francois Jomard, Kamatchi Jothiramalingam Sankaran, Rozita Rouzbahani, Fernando Lloret, Derese Desta, Jan D'Haen, Johan Verbeeck, Michael Frank Becker, Ken Haenen
Summary: This study investigates the influence of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond thin films. The results provide insights into the mechanical properties and intrinsic stress sources of these films, and demonstrate the potential for producing high-quality nanocrystalline diamond films under certain conditions.