Article
Chemistry, Multidisciplinary
Bumsu Park, Ja Kyung Lee, Christoph T. Koch, Martin Woelz, Lutz Geelhaar, Sang Ho Oh
Summary: Growing an InxGa1-xN/GaN multi-quantum well heterostructure in nanowire form can overcome limitations in conventional planar heterostructure LEDs by relaxing the strain induced in the heterostructure through the sidewalls of the nanowire. This study demonstrates techniques for mapping the complex strain distribution within an In0.3Ga0.7N/GaN MQW heterostructure embedded in a GaN nanowire and provides insights into the strain-induced piezoelectric fields in nanowire LEDs.
Article
Chemistry, Multidisciplinary
Erin E. Fleck, Matthew R. Barone, Hari P. Nair, Nathaniel J. Schreiber, Natalie M. Dawley, Darrell G. Schlom, Berit H. Goodge, Lena F. Kourkoutis
Summary: This study presents a semi-automated technique based on STEM images to detect and quantify the presence of different n-phases and quantify the local structure. This method is applicable to a wide range of layered materials.
Article
Chemistry, Multidisciplinary
Dingguo Zheng, Siyuan Huang, Chunhui Zhu, Peng Xu, Zian Li, Hong Wang, Jun Li, Huanfang Tian, Huaixin Yang, Jianqi Li
Summary: The study analyzed the surface plasmonic nearfield structure based on PINEM observations of silver nanowires, revealing plasmon oscillations associated with typical absorption of photon quanta and analyzing the polarization dependence of plasmon wavelength and symmetry properties. By utilizing advanced imaging techniques, the research has implications for future studies of localized-field structures at interfaces and visualization of novel phenomena in nanostructures, nanosensors, and plasmonic devices.
Article
Chemistry, Multidisciplinary
Michelle A. Smeaton, Ismail El Baggari, Daniel M. Balazs, Tobias Hanrath, Lena F. Kourkoutis
Summary: Epitaxially connected quantum dot solids have the potential for highly tunable electronic structures, but defective interdot connections have hindered the realization of predicted emergent electronic properties. In situ heating in the scanning transmission electron microscope has shown that thermal annealing can effectively eliminate tensile and shear defects, while bending defects still persist. Tracking the out-of-plane orientation of individual quantum dots reveals an increase in correctly oriented dots, indicating a relaxation of twisting or bending defects.
Article
Materials Science, Multidisciplinary
Xu Li, Yanyan Ouyang, Ran Zhang, Xingfu Tao, Yongfeng Geng, Shi Li, Yi Zhang, Huifang Gao
Summary: The study uses high resolution transmission electron microscope and geometric phase analysis to investigate strain distribution in GaAs/AlAs multilayer superlattices. It reveals that strains increase farther from the substrate and exhibit anisotropy in different directions. The interface with large strain is more likely to experience cracking or failure.
Article
Nanoscience & Nanotechnology
Jiangtao Qu, Daria Beznasyuk, Maja Cassidy, Rawa Tanta, Limei Yang, Natalie P. Holmes, Matthew J. Griffith, Peter Krogstrup, Julie M. Cairney
Summary: This study demonstrates the importance of correlative microscopy approaches for characterizing the structural and compositional properties of novel semiconductor nanowires. Combination of atom probe tomography and aberration-corrected transmission electron microscopy revealed detailed information about the nanowire arrays.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Nitish Mathur, Fang Yuan, Guangming Cheng, Sahal Kaushik, Inigo Robredo, Maia G. Vergniory, Jennifer Cano, Nan Yao, Song Jin, Leslie M. Schoop
Summary: In this study, a unique internal interface known as a merohedral twin boundary was discovered in chemically synthesized single-crystal nanowires of CoSi. Scanning transmission electron microscopy revealed that this internal interface is a (001) twin plane connecting two enantiomeric counterparts. Ab initio calculations showed the presence of localized internal Fermi arcs at the (001) twin plane, distinct from external Fermi arcs and bulk states. These merohedrally twinned CoSi nanowires provide an ideal platform for exploring topological properties associated with internal interfaces in Weyl semimetals.
Article
Materials Science, Multidisciplinary
Huajie Luo, Hui Liu, Shiqing Deng, Shuxian Hu, Lu Wang, Botao Gao, Shengdong Sun, Yang Ren, Lijie Qiao, Jun Chen
Summary: By introducing oxygen-defect perovskite, the piezoelectric response and depolarization temperature of Bi0.5Na0.5TiO3-BaTiO3 can be simultaneously improved, surpassing the performance limit of similar systems. This method can be extended to other piezoelectric ceramics, providing a new approach for tuning piezoelectric properties.
Article
Chemistry, Physical
Jin-Hu Dou, Maxx Q. Arguilla, Yi Luo, Jian Li, Weizhe Zhang, Lei Sun, Jenna L. Mancuso, Luming Yang, Tianyang Chen, Lucas R. Parent, Grigorii Skorupskii, Nicole J. Libretto, Chenyue Sun, Min Chieh Yang, Phat Vinh Dip, Edward J. Brignole, Jeffrey T. Miller, Jing Kong, Christopher H. Hendon, Junliang Sun, Mircea Dinca
Summary: Researchers have successfully grown single crystals of 2D metal-organic frameworks up to 200 µm in size by balancing in-plane and out-of-plane interactions, revealing anisotropic transport and a clear correlation between conductivity and the nature of the metal cation in the sheets.
Article
Chemistry, Physical
Puspashree Mishra, Rakesh K. Pandey, Soni Kumari, Akhilesh Pandey, Sandeep Dalal, R. Sankarasubramanian, Samartha Channagiri, Suresh K. Jangir, R. Raman, T. Srinivasan, D. V. Sridhara Rao
Summary: Strain balanced InAs/GaSb type-II superlattice structures were grown using molecular beam epitaxy, with InSb-like interfaces introduced to compensate the tensile strain between the constituent binaries. The optimized epilayers exhibit excellent crystalline quality and morphology, with an absorption edge at 5.4 μm in the mid-wave infra-red region, demonstrating a small net strain of 0.0013%.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Stefan Karner, Oliver Blank, Maximilian Roesch, Jakub Zalesak, Jozef Keckes, Christoph Gammer
Summary: This study investigates the residual strain distributions in monocrystalline Si of a modern trench power MOSFET using transmission electron microscopy (TEM) nanobeam electron diffraction (NBED) and finite element (FE) modeling. The results show that strain distributions are influenced by the device structure, geometry, and doping profile in Si.
MICROELECTRONIC ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Taeko Matsukata, F. Javier Garcia de Abajo, Takumi Sannomiya
Summary: Research on exciting nanospheres to generate circularly polarized light emission along arbitrary directions further demonstrates the feasibility of using free-electron-induced light emission in applications such as quantum communication and encryption.
Article
Materials Science, Multidisciplinary
S. Evertz, J. Zalesak, M. Hans, H. C. Jansen, J. F. Keckes, H. Sheng, J. Eckert, C. Gammer, J. M. Schneider
Summary: The atomic distance and composition variations across the interfaces of multilayered thin film metallic glasses were investigated. It was found that there is a chemically graded region and an excess thickness of the atomic distance gradient at the interfaces, which can be rationalized by the presence of strain.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Physical
Zonglin Li, Mingxin Xie, Guozheng Nie, Junhui Wang, Lujun Huang
Summary: In this study, we developed an optical biosensor based on an all-dielectric metasurface with broken symmetry. The biosensor exhibited excellent performance, thanks to the high-Q quasi-bound states in the continuum (qBICs) and the efficient field confinement. It has potential applications in extreme biochemical sensing, such as COVID-19 detection at ultralow concentrations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Libo Fu, Deli Kong, Chengpeng Yang, Jiao Teng, Yan Lu, Yizhong Guo, Guo Yang, Xin Yan, Pan Liu, Mingwei Chen, Ze Zhang, Lihua Wang, Xiaodong Han
Summary: This study demonstrates that ultra-small nanocrystalline gold nanowires with grains in both the Hall-Petch and inverse Hall-Petch grain-size regions exhibit high strength and superplasticity at room temperature. The plastic deformation occurs in two stages, involving intergrain plasticity and intragrain plasticity.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Zequn Zhang, Simon Fellner, Sergey Ketov, Megan J. Cordill, Huaping Sheng, Christian Mitterer, Kaikai Song, Christoph Gammer, Juergen Eckert
Summary: The phase evolution of alloys and atomic diffusion are closely related. However, the influence of reactive diffusion on phase formation in high-entropy alloys (HEAs) is still not clear. This study investigates the phase evolution of a multicomponent CoCrFeNi/Al diffusion couple and reveals the combined effects of enthalpy and entropy on phase formation in HEAs at elevated temperatures. Surface modification of HEAs can be achieved through film deposition and annealing processes.
Article
Materials Science, Coatings & Films
Georg C. Gruber, Alice Lassnig, Stanislav Zak, Christoph Gammer, Megan J. Cordill, Robert Franz
Summary: The thermal stability of three high entropy alloy thin films, based on the system MoNbTaW with additional Cr, Ti or V, was studied. The films were deposited by high power impulse magnetron sputtering, annealed in vacuum up to 1200 degrees C, and analyzed by X-ray diffraction. The body-centered cubic structure remained stable during annealing, and the residual stress reduced with increasing annealing temperature due to defect annihilation.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Chemistry, Physical
Monika Antoni, Florian Spieckermann, Niklas Plutta, Christoph Gammer, Marlene Kapp, Parthiban Ramasamy, Christian Polak, Reinhard Pippan, Michael J. J. Zehetbauer, Juergen Eckert
Summary: The effects of severe plastic deformation (SPD) by means of high-pressure torsion (HPT) on Fe73.9Cu1Nb3Si15.5B6.6 and Fe81.2Co4Si0.5B9.5P4Cu0.8 iron-based metallic glasses were compared. HPT processing extended the consolidation and deformation ranges for Fe73.9Cu1Nb3Si15.5B6.6, and achieved consolidation and deformation with minimum cracks for Fe81.2Co4Si0.5B9.5P4Cu0.8 for the first time. Various analyses revealed that Fe81.2Co4Si0.5B9.5P4Cu0.8 exhibited HPT-induced crystallization phenomena, while Fe73.9Cu1Nb3Si15.5B6.6 did not crystallize even at high HPT-deformation degrees.
Article
Chemistry, Multidisciplinary
Tosson Elalaily, Martin Berke, Mate Kedves, Gergo Fulop, Zoltan Scherubl, Thomas Kanne, Jesper Nygard, Peter Makk, Szabolcs Csonka
Summary: Understanding the microscopic origin of GCS is crucial for engineering superconducting switches. In this study, GCS in a Ta layer on InAs nanowires was investigated. The GCS was found to be determined by gate leakage power. The influence of the gate and temperature on the magnetic field dependence of the supercurrent was also analyzed.
Article
Nanoscience & Nanotechnology
G. Nagda, D. Beznasyuk, J. Nygard, T. S. Jespersen
Summary: In-plane selective area growth of III-V nanowires is important for quantum electronics and photonics applications, but crystal quality optimization is vital. Understanding the role of mis-orientation is important for device design and interpretation of electrical performance. This study investigates the effect of mis-orientation on morphology and material incorporation in selectively grown NWs and shows that using Sb as a surfactant during growth can improve surface roughness for large misalignment.
Article
Chemistry, Multidisciplinary
Benjamin Schuh, Inas Issa, Timo Mueller, Thomas Kremmer, Christoph Gammer, Reinhard Pippan, Anton Hohenwarter
Summary: A nanocrystalline CrMnFeCoNi high-entropy alloy underwent phase decomposition and formed a multi-phase structure after annealing at selected temperatures and times (450 degrees C for 1 h and 15 h and at 600 degrees C for 1 h) following severe plastic deformation by high-pressure torsion. The possibility of tailoring a favorable composite architecture by redistributing, fragmenting, or partially dissolving the additional intermetallic phases was investigated by subjecting the samples to high-pressure torsion again. While the second phase in the 450 degrees C annealing states exhibited high stability against mechanical mixing, partial dissolution could be achieved in the samples subjected to 600 degrees C for 1 h.
Article
Nanoscience & Nanotechnology
Naveen Shetty, Hans He, Richa Mitra, Johanna Huhtasaari, Konstantina Iordanidou, Julia Wiktor, Sergey Kubatkin, Saroj P. Dash, Rositsa Yakimova, Lunjie Zeng, Eva Olsson, Samuel Lara-Avila
Summary: We introduce a reliable and scalable method for fabricating electrical contacts to two-dimensional materials using a tri-layer resist system. This method produces high-quality contacts in devices based on epitaxial graphene on silicon carbide and enables field-effect transistor behavior in transition metal dichalcogenide molybdenum disulfide. The demonstrated fabrication route offers flexibility in contact metallization and is crucial for practical devices and studying emerging materials' electrical properties.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
S. Evertz, J. Zalesak, M. Hans, H. C. Jansen, J. F. Keckes, H. Sheng, J. Eckert, C. Gammer, J. M. Schneider
Summary: The atomic distance and composition variations across the interfaces of multilayered thin film metallic glasses were investigated. It was found that there is a chemically graded region and an excess thickness of the atomic distance gradient at the interfaces, which can be rationalized by the presence of strain.
MATERIALS & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
S. Gonzalez, A. K. Sfikas, S. Kamnis, S. E. John, N. C. Barnard, C. Gammer, J. Eckert, C. G. Garay-Reyes, R. Martinez-Sanchez, S. W. Naung, M. Rahmati, T. Keil, K. Durst, R. J. Lancaster
Summary: High entropy alloys (HEAs) are metallic materials with unique properties due to their chemical composition and atomic arrangement. This research investigated the strain rate sensitivity (SRS) of two HEA CoCrFeMnNiTix (x = 0, 0.3) alloy compositions using shear punch testing. The results showed that only one of the alloy compositions exhibited SRS at room temperature.
MATERIALS & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Georg C. Gruber, Alice Lassnig, Stefan Wurster, Christoph Gammer, Megan J. Cordill, Robert Franz
Summary: In this study, a series of MoNbTaWZr thin films were synthesized using high power impulse magnetron sputtering (HiPIMS) and the structure and properties of the films were analyzed by varying the deposition parameters. The influence of the deposition parameter variation on the films' structure and properties was discussed. This research aims to contribute to the understanding of synthesis-structure-property relations for refractory high entropy alloy thin films.
Article
Chemistry, Multidisciplinary
Daniela Neumueller, Lidija D. Rafailovic, Aleksandar Z. Jovanovic, Natalia V. Skorodumova, Igor A. Pasti, Alice Lassnig, Thomas Griesser, Christoph Gammer, Juergen Eckert
Summary: Highly efficient non-noble metal catalysts are crucial for hydrogen generation through electrolysis, and the synthesis of catalytic heterostructures containing established Ni with surface NiO, Ni(OH)(2), and NiOOH domains has shown promising results. This study investigates the intrinsic catalytic activity of pure Ni and the impact of partial electrochemical oxidation of magnetron sputter-deposited Ni surfaces through various experimental techniques and simulations. The results demonstrate that surface oxidation increases the intrinsic hydrogen evolution reaction (HER) activity of nickel and improves catalyst durability.
Article
Materials Science, Multidisciplinary
H. Q. Nguyen, D. Sabonis, D. Razmadze, E. T. Mannila, V. F. Maisi, D. M. T. Zanten, E. C. T. O'Farrell, P. Krogstrup, F. Kuemmeth, J. P. Pekola, C. M. Marcus
Summary: We demonstrate the electrostatic control of quasiparticle poisoning in superconducting devices using single-charge tunneling across a fixed barrier onto a Coulomb island. High-bandwidth charge sensing is used to monitor the charge occupancy of the island, and electrostatic gates are shown to significantly affect the tunneling rates by two orders of magnitude. The gate dependence of the superconducting gap size and softness on the island is corroborated by separate density-of-states measurements.
Article
Physics, Applied
T. Stavenga, S. A. Khan, Y. Liu, P. Krogstrup, L. DiCarlo
Summary: Quantum hardware based on circuit quantum electrodynamics utilizes airbridges to suppress unwanted wave propagation modes and enable transmission lines to cross. Grayscale lithography is used to reduce the peak temperature of the airbridge fabrication process and increase the physical yield of transmon qubits with Josephson elements.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
D. Razmadze, R. Seoane Souto, L. Galletti, A. Maiani, Y. Liu, P. Krogstrup, C. Schrade, A. Gyenis, C. M. Marcus, S. Vaitiekenas
Summary: We report supercurrent transport measurements in hybrid Josephson junctions consisting of semiconducting InAs nanowires with epitaxial ferromagnetic insulator EuS and superconducting Al coatings. The wires exhibit a hysteretic superconducting window near the coercivity, away from zero external magnetic field. Using a multi-interferometer setup, we measure the current-phase relation of multiple magnetic junctions and observe an abrupt switch between pi and 0 phases within the superconducting window. We attribute the 0-pi transition to the discrete flipping of EuS domains and provide a qualitative theory showing that a sizable exchange field can polarize the junction and lead to the supercurrent reversal. Both 0 and pi phases can be achieved at zero external field by demagnetizing the wire.
Article
Materials Science, Multidisciplinary
O. Erlandsson, D. Sabonis, A. Kringhoj, T. W. Larsen, P. Krogstrup, K. D. Petersson, C. M. Marcus
Summary: The rate of charge-parity switching in a full-shell superconductor-semiconductor nanowire qubit is measured and found to decrease with increasing temperature or magnetic field, resulting in a decrease in the qubit lifetime.
