Article
Energy & Fuels
Aref Samadi, Alison Ciesla, Catherine Chan, Mattias Juhl
Summary: This study provides an alternative interpretation for the trapping-like behavior observed in materials with crystallographic defects. It suggests that the changes in the Fermi energy level at grain boundaries and the movement of majority carriers' quasi Fermi energy level during photoconductance measurement contribute to this behavior. Experimental results using cast-mono silicon wafers show variations in trapping signals and dark conductance that correlate with grain boundaries.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Materials Science, Multidisciplinary
Rita Maji, Eleonora Luppi, Nathalie Capron, Elena Degoli
Summary: This study investigates the effects of oxygen impurity segregation in Sigma 3{111} Si grain boundaries in the presence of strain and vacancies. The research provides insights into the complex mechanisms controlling oxygen atom segregation, offering a foundation for optimizing materials and improving solar cell efficiency.
Article
Chemistry, Multidisciplinary
Songhua Cai, Jun Dai, Zhipeng Shao, Mathias Uller Rothmann, Yinglu Jia, Caiyun Gao, Mingwei Hao, Shuping Pang, Peng Wang, Shu Ping Lau, Kai Zhu, Joseph J. Berry, Laura M. Herz, Xiao Cheng Zeng, Yuanyuan Zhou
Summary: This study resolves the atomic-scale structural information on three prototypical intragrain interfaces using scanning transmission electron microscopy and establishes models for the calculation of electronic properties. The results show that these intragrain interfaces are generally electronically benign, but their interaction with point defects can have detrimental effects. This research contributes to a better understanding of the microscopic structure-property-performance relationship in metal halide perovskites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Pengcheng Jia, Liang Qin, Di Zhao, Yang Tang, Bo Song, Junhan Guo, Xiaomeng Li, Ling Li, Qiuhong Cui, Yufeng Hu, Zhidong Lou, Feng Teng, Yanbing Hou
Summary: The performance of perovskite solar cells is greatly influenced by the crystallization of the perovskite active layer, with neatly arranged crystal grains promoting less residual charge and improved device performance. The testing of residual charge at grain boundaries provides insight into carrier trap and detrap characteristics in photovoltaic devices.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Cassidy M. Atkinson, Matthew C. Guziewski, Shawn P. Coleman, Sanjeev K. Nayak, S. Pamir Alpay
Summary: This study provides a detailed investigation on the formation energies of point defects and the stability of various dopants in bulk cubic silicon carbide and in grain boundaries, as well as the driving force of dopants towards grain boundaries. The results show different behaviors of dopants in grain boundaries, offering a chemical landscape for targeted materials development.
Article
Crystallography
A. G. Chueshova, L. A. Pavlova, S. M. Peshcherova, A. Nepomnyashchikh
Summary: The orientation of grains and the special boundaries in multicrystalline silicon were studied, revealing the existence of certain special boundaries in this material, though not yet experimentally investigated.
CRYSTALLOGRAPHY REPORTS
(2021)
Article
Materials Science, Multidisciplinary
Wei Wan, Changxin Tang
Summary: In this atomistic study, the structure-property correlations of Si (001) small angle mixed grain boundaries (SAMGBs) were investigated. It was found that the energy trends of SAMGBs followed the revised Read-Shockley relationship, and the structural transitions were determined by the dislocation core radii. The proportion, topology and structural signatures of different SAMGB types were also examined.
Article
Materials Science, Multidisciplinary
Masayuki Kamaya, Naoko Maekawa
Summary: Numerous studies have used electron backscatter diffraction to assess plastic strain in polycrystalline materials. However, it is difficult to quantitatively assess the misorientation between adjacent measurement points due to measurement conditions. This study proposes a method for estimating the correlation curve between local misorientation and plastic strain, called the master curve, based on the characteristics of the misorientation parameters under different conditions.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Xiaopu Zhang, Mengyuan Wang, Hailong Wang, Moneesh Upmanyu, John J. Boland
Summary: By using scanning tunneling microscopy and calculations, we investigated the structure of emergent grain boundaries at the surfaces of planar nanocrystalline copper films. We found that there is a strong energetic preference for boundary cores to lie along close-packed planes, which leads to the restructuring of emergent grain boundaries at free surfaces. This new universal mechanism of boundary relaxation at metal surfaces is expected to have an important impact on grain coalescence, film stress evolution, and the properties of nanoscale materials.
Article
Nanoscience & Nanotechnology
Heena Khanchandani, Rolf Rolli, Hans-Christian Schneider, Christoph Kirchlechner, Baptiste Gault
Summary: High-manganese TWIP austenitic steels, known for their exceptional strength and ductility, are susceptible to hydrogen embrittlement which can cause catastrophic failure of engineering parts.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Physical
Wei Wan, Changxin Tang, Wennan Zou
Summary: This study used a high efficient MC/MD approach to reproduce silicon [001] small angle symmetric tilt grain boundaries, focusing on the variations of grain boundary properties under different misorientation angles and the roles of dislocation stress fields in shaping special grain boundary properties. Calculations of key parameters for grain boundary structures and energies were conducted, which could benefit future grain boundary engineering.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
S. Hemery, J. C. Stinville, F. Wang, M. A. Charpagne, M. G. Emigh, T. M. Pollock, V. Valle
Summary: The study identified a unique crack nucleation mechanism involving strain localization at (0001) twist boundaries in titanium alloys, with crack initiation preferentially occurring at twist angles spanning the 10 degrees - 20 degrees range. The (0001) twist boundaries are preferred locations for early and intense strain localization, and deformation prior to crack initiation proceeds via shear along these boundaries.
Article
Chemistry, Multidisciplinary
Yusuke Fukuda, Kentaro Kutsukake, Takuto Kojima, Noritaka Usami
Summary: This study investigates the effects of grain boundary structure on the growth direction of grain boundaries and reveals different growth patterns for different orientations. It suggests that grain boundaries with shallow energy grooves are more likely to grow away from the seed-oriented direction.
Article
Materials Science, Multidisciplinary
Zicheng Xie, Jie Zhang, Yu Xiao, Yangcenzi Xie, Wenkun Zhu, Shuyi Yu, Tingting Hou, Shuquan Liang, Liangbing Wang
Summary: Grain boundaries in metal oxides are found to easily regulate reactive oxygen species (ROS) in aerobic oxidation reactions. MoO3-600 nanocrystals with high density of grain boundaries exhibit excellent catalytic performance and selectivity in the aerobic oxidation process.
ENERGY & ENVIRONMENTAL MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Bahareh Marzban, Lukas Seidel, Teren Liu, Kui Wu, Vivien Kiyek, Marvin Hartwig Zoellner, Zoran Ikonic, Joerg Schulze, Detlev Grutzmacher, Giovanni Capellini, Michael Oehme, Jeremy Witzens, Dan Buca
Summary: SiGeSn materials show great potential for mid-infrared applications. In this study, an electrically pumped GeSn microring laser based on SiGeSn/GeSn heterostructures is demonstrated. The ring shape allows for enhanced strain relaxation, leading to improved optical properties and carrier guiding. Partial undercutting of the ring further promotes strain relaxation while maintaining adequate heat sinking. Lasing is achieved at temperatures up to 90 K, with a T0 of 75 K. The scaling of the threshold current density with the inverse of the outer circumference is attributed to optical losses at the etched surface. The results of this study will guide further optimization of the device towards improving electrical injection and increasing the bandgap directness of the active material using stressors.
Article
Multidisciplinary Sciences
Yaxin Chen, Daiming Tang, Zhiwei Huang, Xi Liu, Jun Chen, Takashi Sekiguchi, Weiye Qu, Junxiao Chen, Dongrun Xu, Yoshio Bando, Xiaolei Hu, Xiaoping Wang, Dmitri Golberg, Xingfu Tang
Summary: The study successfully fabricated stable atomic silver wires (ASWs) with excellent conductivity and stability, which could be applied in thermal electrical devices.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Jun Chen, Wei Yi, Shun Ito, Takashi Sekiguchi
Summary: The extended defects in m-plane seed-grown GaN substrate, specifically the presence of basal-plane stacking faults (BSFs), have been studied using cathodoluminescence (CL) and transmission electron microscopy (TEM). The luminescence characteristics and emission peaks of I-1 and I-2 BSFs have been identified through high-resolution CL and spatially resolved spectral analysis. Additionally, the movement of dislocations under electron beam irradiation and its correlation with stacking faults have been discussed.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
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
Jun Uzuhashi, Jun Chen, Ashutosh Kumar, Wei Yi, Tadakatsu Ohkubo, Ryo Tanaka, Shinya Takashima, Masaharu Edo, Kacper Sierakowski, Michal Bockowski, Hideki Sakurai, Tetsu Kachi, Takashi Sekiguchi, Kazuhiro Hono
Summary: An investigation on annealing under different conditions after magnesium (Mg) implantation into GaN crystals revealed that ultra-high-pressure annealing (UHPA) effectively suppresses the formation of Mg-enriched defects, leading to improved p-type activation efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Jia He, Jun Chen, Cheng Zheng, Zetan Cao, Zhiwen Liu, Chuangwei Jiao, Bin Chen, Takashi Sekiguchi, Dongping Zhong
Summary: This study presents a facile strategy of using antisolvent droplets for assisting the crystallization and growth of large high-quality perovskite bulk crystals at room temperature. The composition of the solvents used during growth can be tuned to control the formation of different types of bulk crystals. The results also reveal the solvation-like effect between the photocarriers and surrounding lattices in these bulk crystals.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Engineering, Environmental
Can He, Takashi Takeda, Zhaohui Huang, Jian Xu, Jun Chen, Wei Yi, Rongjun Xie, Naoto Hirosaki
Summary: The novel needle-like Ba5Si11Al7N25:Eu2+ phosphor exhibits a broad yellow emission band centered at 570 nm. Compared with YAG: Ce phosphor, it has a longer emission wavelength, indicating potential application in warm white LEDs.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Physics, Applied
Ashutosh Kumar, Wei Yi, Tadakatsu Ohkubo, Jun Chen, Takashi Sekiguchi, Ryo Tanaka, Shinya Takashima, Masaharu Edo, Kazuhiro Hono
Summary: We investigated the impact of high-temperature Mg-implantation on the distribution of Mg-enriched defects in GaN layers. By using scanning transmission electron microscopy and atom probe tomography, we observed fewer Mg-enriched defects in the sample implanted at 1000℃ compared to the sample implanted at room temperature. The implantation of Mg ions at 1000℃ resulted in more uniform and enhanced donor-acceptor pair emission, leading to higher Mg activation.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Jun Chen, Hiroyuki Sazawa, Wei Yi, Takashi Sekiguchi
Summary: High-quality 3C-SiC epilayers can be grown on 4H-SiC substrates by controlling step growth and proper surface pretreatment. The optical and electrical properties of extended defects in 3C-SiC were investigated using cathodoluminescence (CL) spectroscopy. The impact of surface pretreatment on the growth of high-quality 3C-SiC is discussed.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
Chuangwei Jiao, Zetan Cao, Jia He, Zhiwen Liu, Linfeng Xu, Cheng Zheng, Simin Peng, Guliziba Haldu, Bin Chen
Summary: The rapid development of metal-organic frameworks (MOFs) has led to their applications in catalysis, adsorption, separation/purification, and energy storage. However, there is a need for new re-engineering options to enhance their functions. In this study, we demonstrate a simple and effective strategy to tune MOFs into hollow nanostructures using halide anions. The resulting derivatives show improved hydrogen evolution reaction activity and long-term electrochemical stability compared to the pristine MOFs.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Zetan Cao, Jia He, Chuangwei Jiao, Zhiwen Liu, Linfeng Xu, Cheng Zheng, Simin Peng, Bin Chen
Summary: Enantiomeric control of intrinsically chiral inorganic nanocrystals was achieved through enantioselective synthesis using chiral amino acids. The chiroptical activity of the nanocrystals could be tailored by adjusting the Cs/Cu feed ratios and amino acid types. This strategy enables the controllable synthesis of intrinsically chiral inorganics and provides insights into the origins of chiral discrimination and crystallization phenomena.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Chuangwei Jiao, Zetan Cao, Jia He, Zhiwen Liu, Cheng Zheng, Simin Peng, Bin Chen
Summary: Hollow metallic Co@Co cages were successfully synthesized using a simple two-step strategy, showing excellent catalytic performance due to abundant exposed active sites and fast charge transfer. The low overpotential of Co@Co(C) in the hydrogen evolution reaction suggests its potential as a catalyst comparable to Pt/C electrodes. This two-step synthesis strategy opens up opportunities for improving catalytic activity and charge/mass transfer rates in MOF-based nanostructures.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Zetan Cao, Jia He, Chuangwei Jiao, Zhiwen Liu, Linfeng Xu, Cheng Zheng, Simin Peng, Bin Chen
Summary: In this study, the enantioselective synthesis of intrinsically chiral perovskite-like CsCuCl3 nanocrystals was achieved at room temperature using chiral amino acids as additives in an antisolvent crystallization method. The resulting D-/L-ligand-induced enantiomeric nanocrystals exhibited characteristic chiroptical responses. By adjusting the amino acid types and Cs/Cu feed ratios, the chiroptical activity of the nanocrystals could be controlled. This research opens up new pathways for the controllable synthesis of intrinsically chiral inorganic materials and provides a better understanding of the origins of precursor-ligand-associated chiral discrimination and crystallization phenomena.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
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
Summary: In this study, we used PES and PEH techniques to investigate the atomic structures and chemical states in the active and inactive dopant states of Mg-doped GaN. The results revealed the presence of two chemical states, with the active state being attributed to Mg atoms replacing Ga atoms in the GaN structure, and the inactive state potentially being a disordered structure or defects.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
