Article
Nanoscience & Nanotechnology
Ganapathi Prabhu Sai Balasubramanian, Elizaveta Lebedkina, Nebile Isik Goktas, Jakob Birkedal Wagner, Ole Hansen, Ray LaPierre, Elizaveta Semenova, Kristian Molhave, Marco Beleggia, Elisabetta Maria Fiordaliso
Summary: Off-axis electron holography was used to observe remote doping in GaAs nanowires during in situ annealing in a transmission electron microscope. Dynamic changes in electrostatic potential caused by carbon dopant diffusion upon annealing were measured, and the electrostatic potential profiles were extracted from GaAs nanowires with radial p-p+ core-shell junctions. The experiment showed that the built-in potentials remained nearly constant and the depletion layer widths slightly increased, contrary to the predictions made in the absence of remote doping. A depression in the potential profile of the core upon annealing was also observed, which was attributed to carbon diffusion from the shell to the core through the nanowire sidewalls.
Article
Chemistry, Multidisciplinary
Timothee Lassiaz, Pierre Tchoulfian, Fabrice Donatini, Julien Brochet, Romain Parize, Gwenole Jacopin, Julien Pernot
Summary: The paper demonstrates the assessment of depletion width and doping profile at the nanoscale of individual microwire core-shell light-emitting devices using capacitance-voltage measurements. A statistical study shows consistency in doping profile values between individual microwires and assemblies of hundreds of wires on the same sample. The robustness of the method is further demonstrated on four epitaxial structures with different growth and doping conditions, and electron-beam-induced current and secondary electron profiles are used to validate depletion region width and position in the core-shell structure.
Article
Computer Science, Software Engineering
Praneeth Chakravarthula, Seung-Hwan Baek, Florian Schiffers, Ethan Tseng, Grace Kuo, Andrew Maimone, Nathan Matsuda, Oliver Cossairt, Douglas Lanman, Felix Heide
Summary: Holographic displays offer enhanced display capabilities in augmented reality applications, but the sampling of the holographic field by the eye pupil poses a challenge. This study introduces a pupil-aware holography approach that maximizes perceptual image quality regardless of the eye pupil's size, location, and orientation. Experimental results show that the proposed method eliminates severe artifacts and outperforms existing approaches.
ACM TRANSACTIONS ON GRAPHICS
(2022)
Article
Optics
Mostafa Agour, Claas Fallorf, Fatima Taleb, Enrique Castro-Camus, Martin Koch, Ralf B. Bergmann
Summary: This contribution demonstrates the first referenceless measurement of a THz wavefront using shear-interferometry. The technique utilizes a specific grating and imaging system parameters to generate shear, and employs an iterative algorithm for wavefront reconstruction.
Article
Optics
Soma Fujimori, Tomoyoshi Ito, Tomoyoshi Shimobaba
Summary: This paper proposes a method to reduce aliasing in Fresnel diffraction, which involves both scaling and shift. The proposed method is based on the sampling theorem and the Fourier shift theorem. Numerical verification and theoretical formulations demonstrate its effectiveness, with a limited increase in computation time and improved signal-to-noise ratio compared to the conventional method.
OPTICS AND LASERS IN ENGINEERING
(2024)
Article
Physics, Applied
Michael A. A. Gribelyuk, Sanjay Mehta, Jeffrey B. Johnson, Lee Kimball
Summary: This paper presents a methodology to map dopant potential in modern FinFET devices and suggests a dopant reconstruction method to account for the non-uniformity of materials. It offers a new research approach for the development of nanometer scaled FinFET devices.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Computer Science, Software Engineering
Praneeth Chakravarthula, Ethan Tseng, Henry Fuchs, Felix Heide
Summary: Holography is a promising avenue for high-quality displays, but existing limitations such as wavefront modeling and unit element encoding have hindered its full potential. The newly proposed hogel-free holography overcomes these limitations and supports true 3D holographic effects.
ACM TRANSACTIONS ON GRAPHICS
(2022)
Article
Multidisciplinary Sciences
Sergey Zayko, Ofer Kfir, Michael Heigl, Michael Lohmann, Murat Sivis, Manfred Albrecht, Claus Ropers
Summary: The study demonstrates an ultrafast microscopy based on high-harmonic radiation for direct imaging of ultrafast phenomena and capturing femtosecond spin dynamics at the nanoscale. Real-space magnetic imaging allows for observation of local magnetization dynamics, with implications for studying non-equilibrium magnetic evolution. The ultrafast imaging technique provides high spatio-temporal resolution, offering potential applications in magnetism, phase transitions, and carrier dynamics.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Takayoshi Yokoya
Summary: Photoelectron holography is an experimental technique that allows the study of the three-dimensional local structure around a focused atom. Recent advancements in reconstruction algorithms and the utilization of high-intensity soft X-rays have made it possible to reveal detailed dopant local structures. This technique can estimate dopant occupancy and determine the orientation of dopant vacancy complexes.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Review
Nanoscience & Nanotechnology
Bernard C. Kress, Ishan Chatterjee
Summary: The paper reviews and analyzes the implementation architectures of diffractive waveguide combiners for AR, MR, and smart glasses, highlighting the potential of these devices to revolutionize various aspects of daily life. However, challenges such as comfort and immersion need to be addressed through a human-centric optical design process, matching display architecture to human visual perception. This deep understanding of human perception is crucial for delivering both a comfortable and immersive experience to end users while ensuring reasonable production costs.
Article
Nanoscience & Nanotechnology
Saswata Mukherjee, Quentin A. A. Tanguy, Johannes E. Froch, Aamod Shanker, Karl F. Bohringer, Steven Brunton, Arka Majumdar
Summary: Ultrathin flat meta-optics have shown promise for holography, but most reported holograms only modulate phase and neglect amplitude. Complex phase modulation typically requires polarization-sensitive meta atoms or complex scatterers. This study demonstrates polarization-independent holography with both amplitude and phase modulation using dielectric meta-optics. The researchers also show that meta-optical holography can be achieved using partially incoherent light from an LED, reducing alignment complexity.
Article
Materials Science, Multidisciplinary
Yu Zhang, Giuseppe Scardera, Shaozhou Wang, Malcolm Abbott, David Payne, Bram Hoex
Summary: Phosphorous dopant diffusion profiles are important in many silicon semiconductor devices, and accurate spatially resolved dopant profiling is crucial for understanding their performance. The scanning electron microscopy for dopant contrast imaging (SEMDCI) method is effective in obtaining these profiles, especially for silicon samples with surface nanotexturing or black silicon (BSi) technology. However, previous studies have shown a poor correlation between the dopant concentration and the secondary electron (SE) signal contrast. This work presents improvements in contrast, correlation, and image condition normalization, and applies the SEMDCI method for the first time to obtain 2D electron concentration maps for planar and BSi samples.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Physics, Applied
Anup Kumar Sahoo, Wei-Chen Au, Yu-Cheng Hong, Ci-Ling Pan, Dongwei Zhai, Emilie Herault, Frederic Garet, Jean-Louis Coutaz
Summary: This study investigates the use of terahertz time-domain spectroscopy (THz-TDS) as a non-destructive and non-contact technique for depth profiling of dopants in semiconductors. The results show that THz-TDS has great potential in dopant depth profiling and is consistent with other measurement methods and simulations.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Multidisciplinary Sciences
Wenbo Wang, Zheng Zhang, Pengpeng Wang, Yaqi Zhao, Feng Zhang, Cunjun Ruan
Summary: In this paper, a 220 GHz broadband and high-power staggered double-vane traveling-wave tube is designed and verified. The proposed scheme is expected to develop a high-power and ultra-wideband terahertz band radiation source with potential applications in the future.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Andreas Erik Gejl Madsen, Rene Lynge Eriksen, Jesper Gluckstad
Summary: This study examines the use of a Convolutional Neural Network for generating digital holograms and compares it to state-of-the-art iterative methods. While the neural network outperforms the original GS algorithm in reconstruction quality, it lags behind in speed compared to modern optimized GS implementations.
OPTICS COMMUNICATIONS
(2022)
Article
Polymer Science
Sajan Singh, Andriy Horechyy, Sushma Yadav, Petr Formanek, Rene Huebner, Rajiv K. Srivastava, Sameer Sapra, Andreas Fery, Bhanu Nandan
Summary: A unique perforated lamellar (PL) morphology was observed in a mixture of an asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer and CdSe-CdS quantum dots (QDs). The CdSe-CdS QDs were localized exclusively in the P4VP perforations, contributing to the energetically stabilized PL morphology. This study reveals possibilities for novel hierarchical structures in block copolymer/nanoparticle composite systems and offers new opportunities for their application in nanotechnology.
Article
Nanoscience & Nanotechnology
Christos K. Mytafides, Lazaros Tzounis, George Karalis, Petr Formanek, Alkiviadis S. Paipetis
Summary: The study introduces the fabrication process of a highly efficient fully printed all-carbon organic thermoelectric generator (OTEG) that does not require metallic junctions. The novel OTEG exhibits outstanding flexibility and stability with exceptional power output, making it possible to operate at high temperatures up to 200 degrees Celsius. The device has been successfully designed with superior thermoelectric properties, providing opportunities for large-scale manufacturing of efficient flexible OTEGs.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Mariia Zhyhailo, Andriy Horechyy, Jochen Meier-Haack, Petr Formanek, Mikhail Malanin, Kerstin Arnhold, Konrad Schneider, Iryna Yevchuk, Andreas Fery
Summary: The study introduces a method to prepare hybrid proton conductive membranes by simultaneously conducting photo-initiated polymerization and sol-gel processing. The addition of 3-methacryloxypropyl trimethoxysilane into the sol-gel composition enables the formation of covalent linkages between polymeric and inorganic networks, improving water retention and proton conductivity of the hybrid membranes.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2021)
Article
Biochemistry & Molecular Biology
Maren Gueltner, Regine Boldt, Petr Formanek, Dieter Fischer, Frank Simon, Petra Poetschke
Summary: In this study, PC, SAN, MWCNTs/SWCNTs, and RC were melt compounded in a microcompounder. The localization of MWCNTs was found to be influenced by adjusting the RC concentration, while the localization of SWCNTs in PC/SAN-RC blends depended on their types.
Article
Nanoscience & Nanotechnology
Shib Shankar Banerjee, Subhradeep Mandal, Injamamul Arief, Rama Kanta Layek, Anik Kumar Ghosh, Ke Yang, Jayant Kumar, Petr Formanek, Andreas Fery, Gert Heinrich, Amit Das
Summary: This study presents a novel method to prepare liquid metal-embedded soft elastomeric composites, showing significant improvements in mechanical properties and enhanced thermal and dielectric performance.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Biomaterials
Paul Simon, Wolfgang Pompe, Manfred Bobeth, Hartmut Worch, Ruediger Kniep, Petr Formanek, Anne Hild, Sabine Wenisch, Elena Sturm
Summary: The degradation mechanism of human trabecular bone from the central part of the femoral head in a patient with senile osteoporosis was investigated. Severe damages were observed due to osteoclasts and podosome activity, resulting in the disintegration of bone structure. Podosomes create pit marks and holes on the bone surface, leading to the formation of microcracks and a brittle, porous bone structure.
ACS BIOMATERIALS SCIENCE & ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Sajan Singh, Avinash Raulo, Ajeet Singh, Mona Mittal, Andriy Horechyy, Rene Huebner, Petr Formanek, Rajiv K. Srivastava, Sameer Sapra, Andreas Fery, Bhanu Nandan
Summary: In this study, the influence of gold nanoparticles (AuNPs) on the photoluminescence behavior of cadmium selenide (CdSe) quantum dots (QDs) confined in spatially separated soft nanoscale cylindrical domains was investigated. It was found that the presence of AuNPs can manipulate the photoluminescence intensity of CdSe QDs, with low fraction of AuNPs leading to enhancement and further increase causing quenching of the intensity. The interaction between energy transfer mechanisms and FRET/electron transfer processes between QDs and AuNPs could explain the observed phenomena.
Article
Nanoscience & Nanotechnology
Takuya Tsuda, Soosang Chae, Mahmoud Al-Hussein, Petr Formanek, Andreas Fery
Summary: A piezoresistive pressure sensor based on doped semiconducting polymer nanopillars with controlled elastic buckling has been developed, allowing for the detection of pressure over a wide range with good sensitivity, reproducibility, and cycling stability.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Energy & Fuels
George Karalis, Lazaros Tzounis, Christos K. Mytafides, Kyriaki Tsirka, Petr Formanek, Minas Stylianakis, Emmanuel Kymakis, Alkiviadis S. Paipetis
Summary: In this work, a water-based Te nanowires synthesis method and formulation of hybrid thermoelectric inks using PEDOT:PSS were demonstrated for creating high performance and flexible printed thermoelectric generators. Characterization techniques confirmed the high crystallinity of the Te nanowires, microstructural features, and carrier density and mobility of the materials. A flexible TEG with promising power output was fabricated, showcasing the potential for large-scale production and thermal energy harvesting using printed TEG devices.
Article
Chemistry, Physical
Xueyi Wang, Silvia Moreno, Susanne Boye, Ping Wen, Kehu Zhang, Petr Formanek, Albena Lederer, Brigitte Voit, Dietmar Appelhans
Summary: The study developed an artificial organelles system with stimuli-triggered regulation ability, achieving pH regulation by triggering out-of-equilibrium state with chemical fuels, providing a new approach for constructing artificial eukaryotic cell biomimetics.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Christos K. Mytafides, Lazaros Tzounis, George Karalis, Petr Formanek, Alkiviadis S. Paipetis
Summary: This study successfully fabricated a fully printed carbon nanotube-based Thermoelectric Generator (TEG) with excellent flexibility and remarkable power output, capable of operating at high temperatures up to 350 degrees C. The TEG device, easily manufactured through low-cost ink printing processes, exhibited remarkable power factors on high-temperature resistant substrates, along with exceptional stability in air. The produced TEG showed high thermoelectric performance in the field of carbon-based and printed thermoelectric devices, with the potential for large-scale manufacturing opportunities.
JOURNAL OF POWER SOURCES
(2021)
Article
Polymer Science
Bjoern Guenther, Thomas Kremser, Markus Susoff, Petr Formanek, Andreas Fery, Sven Wiessner
Summary: This study investigated the influence of masterbatches with different carrier resins on the impact resistance and morphology of an ABS/SAN blend. It found that masterbatches based on PS led to immiscibility, while those based on ABS and SAN showed no significant impact. Theoretical calculations were in good accordance with experimental results, suggesting the potential for predicting suitable masterbatch carriers based on solubility calculations between blend partners.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Kumari Sushmita, Petr Formanek, Beate Krause, Petra Poetschke, Suryasarathi Bose
Summary: This study explores the impact of functionalization and distribution of carbon nanotubes (CNTs) in polymer matrices or blends on the electromagnetic interference (EMI) shielding performance of nanocomposites. It is found that despite a decrease in electrical conductivity, ball-milled CNTs may not necessarily lead to a drastic decrease in shielding effectiveness. In addition to the compartmentalization of CNTs, the state, dispersion, and distribution of CNTs also play a significant role in determining the final properties of the composites.
ACS APPLIED NANO MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yixuan Du, Yue Li, Olha Aftenieva, Takuya Tsuda, Petr Formanek, Tobias A. F. Koenig, Alla Synytska
Summary: This paper reports for the first time the high-yield synthesis of water-processable donor-acceptor Janus nanoparticles (JNP) and demonstrates their high potential for optoelectronic applications. The JNPs show easily controlled Janus ratios and excellent quality, as confirmed by energy-filtered transmission electron microscopy. Compared to conventional donor-acceptor nanoparticles, the JNPs exhibit improved charge separation and transfer properties, as characterized by both steady-state and transient photoluminescence spectroscopy. The Janus character of the particles enables the combination of two materials into one composite and allows for the programming of structure morphology. Lastly, the JNP-based photovoltaic cells demonstrate outstanding performance with a 53% improvement in efficiency.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Polymer Science
Carolin Bunk, Hartmut Komber, Michael Lang, Nora Fribiczer, Martin Geisler, Petr Formanek, Lothar Jakisch, Sebastian Seiffert, Brigitte Voit, Frank Boehme
Summary: In this study, two well-defined amphiphilic tetra-arm star block copolymers were prepared by a hetero-complementary linking reaction. The behavior of the two copolymers was studied in water, and it was found that spherical micelles formed at elevated temperatures for the copolymer with longer PEG arms. However, the copolymer with shorter PEG arms formed cloudy suspensions in water.
Article
Microscopy
C. Gao, C. Hofer, T. J. Pennycook
Summary: Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, contrast reversals can occur when the projected potential becomes strong. Recent research has shown that these reversals can be counteracted by adapting the focus. This study explains why the best contrast is often found with the probe focused to the middle of the sample and highlights the importance of convergence angle in thin samples to remove contrast reversals.
Article
Microscopy
J. Lindner, U. Ross, T. Meyer, V. Boureau, M. Seibt, Ch. Jooss
Summary: Phase-shifting electron holography is an excellent method with high phase sensitivity to reveal electron wave phase information. An advanced drift correction scheme is proposed in this study, which exploits the interface of the TEM specimen and the vacuum area in the hologram. This method allows for obtaining reliable phase information.
Article
Microscopy
Ali Jaberi, Nicolas Brodusch, Jun Song, Raynald Gauvin
Summary: This study investigates knock-on damage in lithium-ion batteries (LIBs) by computing threshold displacement energies (TDEs) and performing Monte Carlo simulation. The results indicate that Li is most sensitive to knock-on damage at moderate electron energies, and TDE is the principal parameter for assessing Li sensitivity to knock-on damage across similar structures.
Article
Microscopy
Alexander Schroeder, Christopher Rathje, Leon van Velzen, Maurits Kelder, Sascha Schaefer
Summary: This study utilizes novel event-based electron detector platforms to extend the temporal resolution of electron microscopy. By training a neural network to predict electron arrival time, the researchers were able to improve the timing accuracy and achieve a promising solution for enhancing electron timing precision in various electron microscopy applications.
Article
Microscopy
Avi Auslender, Nivedita Pandey, Amit Kohn, Oswaldo Dieguez
Summary: This article describes a faster implementation based on DFT for computing the mean inner potential of crystals, providing quantum-mechanical calculations beyond the independent-atom approximation. The study also reveals the dependence of the mean inner potential on sample boundary conditions, mass density, and magnetic susceptibility, highlighting its correlation with various material properties.
Article
Microscopy
Zhidong Yang, Dawei Zang, Hongjia Li, Zhao Zhang, Fa Zhang, Renmin Han
Summary: In this work, we propose a self-supervised deep learning model for cryo-ET volumetric image denoising based on noise modeling and sparsity guidance. Experimental results demonstrate that our method can achieve reliable denoising by training on single noisy volume and outperform existing methods.
Article
Microscopy
J. Kuttruff, J. Holder, Y. Meng, P. Baum
Summary: In this study, a robust clustering algorithm is proposed that can find clusters in a continuous stream of raw data in real time. This algorithm converts pixel hits measured by hybrid pixel detectors to real single-electron events. By continuously comparing with previous hits, the algorithm efficiently identifies the merging of new and old events.
Article
Microscopy
D. G. Senturk, C. P. Yu, A. De Backer, S. Van Aert
Summary: This article presents a statistics-based method for accurately counting the number of atoms in nanostructures, especially for images acquired with low electron doses and multiple element structures.
Article
Microscopy
Mauricio J. Prieto, Lucas de Souza Caldas, Liviu C. Tanase, Thomas Schmidt, Oscar Rodriguez de la Fuente
Summary: This study presents a synchrotron-based investigation of the synthesis process of a magnetite/hematite bilayer. Ion bombardment gradually transforms hematite into magnetite, and the growth of magnetite leads to the formation of stable boundaries. These findings are significant for understanding novel oxide heterostructures.
Article
Microscopy
Emre Yoruk, Holger Klein, Stephanie Kodjikian
Summary: Beam sensitive nanomaterials pose challenges for crystallographic structure determination. A dose symmetric electron diffraction tomography (DS-EDT) method is developed to reduce beam damage and obtain complete data sets by merging individual datasets from multiple crystals.
Article
Microscopy
A. Pofelski, Y. Zhu, G. A. Botton
Summary: The precision and sensitivity of the GPA method for strain characterization is a widely discussed topic. This study introduces the concept of phase noise and analyzes the parameter of sampling to improve the precision of GPA. Experimental and theoretical results demonstrate that using a larger pixel spacing in STEM can enhance the precision and sensitivity of the GPA method.
Article
Microscopy
Sangjun Kang, Di Wang, Christian Kuebel, Xiaoke Mu
Summary: Transmission electron microscopy is a valuable tool for assessing strain fields within materials. However, using thin specimens in TEM analysis can affect atomic configuration and deformation structure.