Article
Chemistry, Analytical
Yufei Wang, Mingyang Li, Emma Gordon, Zhijiang Ye, Hang Ren
Summary: Understanding the structure-activity relationship in electrochemical metal dissolution reactions is crucial for designing higher density batteries and mitigating corrosions. The kinetics of metal dissolution is strongly influenced by surface structures, such as grain boundaries and defects. However, directly probing the electrochemical activity at these sites is challenging due to the limitation of conventional bulk electrochemistry. In this study, the colocalized mapping of an electrochemical metal dissolution reaction using Ag as a model system is reported. The local dissolution kinetics is measured using scanning electrochemical cell microscopy (SECCM) and correlated with the local structures obtained via colocalized electron backscattering diffraction (EBSD). The findings reveal the importance of nanoscale local electrochemical mapping and colocalized microscopic measurement in understanding the structure-activity relationship for electrochemical reactions at complex interfaces.
ANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Simon Grall, Ivan Alic, Eleonora Pavoni, Mohamed Awadein, Teruo Fujii, Stefan Muellegger, Marco Farina, Nicolas Clement, Georg Gramse
Summary: Electrochemical microscopy techniques have expanded the understanding of surface chemistry to micrometer and sub-micrometer levels. This study introduces local cyclic voltammetry measurements with sub-atto-Ampere sensitivity and spatial resolution < 80 nm at the solid-liquid interface on a ferrocene self-assembled monolayer. The high sensitivity is achieved through measurements of the charging of the local faradaic interface capacitance at GHz frequencies, allowing for nanometer-scale details of different molecular organizations with minimal dispersion in molecular electrical properties.
Article
Materials Science, Ceramics
Fugang Lu, Ce Wang, Jiujie Xu, Zhanguo Liu, Panpan Lin, Tiesong Lin, Jincheng Lin, Xinfei Zhang, Xinyue Li, Peng He
Summary: Excess Li compensation powder (ECP) can be used as a covering powder in the pressureless sintering of Li-garnet solid electrolytes, optimizing the microstructure and improving the density and ionic conductivity.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
Peng Fan, Hui Chen, Xingtai Zhou, Lu Cao, Geng Li, Meng Li, Guojian Qian, Yuqing Xing, Chengmin Shen, Xiancheng Wang, Changqing Jin, Genda Gu, Hong Ding, Hong-Jun Gao
Summary: We demonstrate the manipulation of Abrikosov vortices on the surfaces of Fe(Te,Se) and LiFeAs by utilizing one-dimensional wrinkles and low-temperature scanning tunneling microscopy/spectroscopy (STM/S). The wrinkles trap the Abrikosov vortices induced by the external magnetic field, and we are able to tailor and manipulate the wrinkles using an STM tip. Surprisingly, we show that the pinned vortices move together with these wrinkles even at high magnetic field up to 6 T. This work provides a universal and effective method for manipulating wrinkle-pinned vortices and simultaneously measuring the local density of states on the surfaces of iron-based superconductors.
Article
Chemistry, Multidisciplinary
Nicolas Neel, Joerg Kroeger
Summary: The study revealed that the formation of a chemical bond between a CO molecule and a Cu(111) surface is accompanied by bending of the molecular probe due to van der Waals attraction and Pauli repulsion, resulting in characteristic changes in the vertical force between CO and Cu(111) as a function of molecule-surface distance. Experimental data were successfully reproduced by model calculations, shedding new light on vertical-force extrema in scanning probe experiments.
Article
Chemistry, Multidisciplinary
Yuhiro Segawa, Kenji Yamazaki, Jun Yamasaki, Kazutoshi Gohara
Summary: A new method for measuring the 3D atomic structure of free-standing graphene ripples using TEM is proposed and experimentally validated. The specimen in the experiment was found to be moving upward, and the ripple was approximated as a composite of sinusoidal waves while measuring the time dependence of its height and lateral size.
Article
Nanoscience & Nanotechnology
A. N. Chaika, S. Bozhko, A. M. Ionov, I Sveklo, E. Yu Postnova, V. N. Semenov, A. Bisht, E. Rabkin
Summary: The solid state dewetting of a ten monolayers thick Ag film on periodically patterned Si(557) surface leads to the formation of faceted single crystalline Ag nanoparticles with bimodal size distribution when annealed at temperatures between 300 and 400 degrees C. Some particles contain screw dislocations producing a step on the upper particle facet.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Multidisciplinary
Caleb Z. Zerger, Linsey K. Rodenbach, Yi-Ting Chen, Benjamin Safvati, Morgan Z. Brubaker, Steven Tran, Tse-An Chen, Ming-Yang Li, Lain-Jong Li, David Goldhaber-Gordon, Hari C. Manoharan
Summary: This research demonstrates that the Cu(111) surface state under wafer-scale hBN is homogeneous in energy and spectral weight over nanometer length scales and across atomic terraces. However, a new spectral feature that is not observed on bare Cu(111) varies with atomic registry and shares the spatial periodicity of the hBN/Cu(111) moire.
Article
Chemistry, Multidisciplinary
Kaihui Li, Feiping Xiao, Wen Guan, Yulong Xiao, Chang Xu, Jinding Zhang, Chenfang Lin, Dong Li, Qingjun Tong, Si-Yu Li, Anlian Pan
Summary: Moire superlattices exhibit a magnification effect and are sensitive to both external disturbances and internal atomic reconstructions. Long-wavelength WS2 superlattices can be reconstructed into various moire morphologies, ranging from regular hexagons to heavily deformed shapes. The interaction between external nonuniform heterostrain and intrinsic atomic reconstruction is responsible for this interesting evolution of moire structures.
Article
Chemistry, Physical
Denis V. Lebedev, Vitaly A. Shkoldin, Alexey M. Mozharov, Artem O. Larin, V. Dmitry Permyakov, Anton K. Samusev, Anatoly E. Petukhov, Alexander O. Golubok, V. Alexander Arkhipov, Ivan S. Mukhin
Summary: This work presents a simple approach to fabricate nanoscale electrically driven light sources based on the phenomenon of light emission via inelastic tunneling of electrons. By using STM lithography, hybrid nanoantennas with a minimum diameter of 60 nm were formed, which can efficiently emit photons in the visible range.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Review
Chemistry, Physical
Chunlei Yang, Tianhui Su, Yanbo Hua, Liming Zhang
Summary: This review summarizes the latest results of electrochemical scanning probe microscopy techniques in studying the interfacial properties of electrocatalysts and photoelectrodes, and offers some perspectives on future research directions.
Article
Chemistry, Multidisciplinary
Donglin Li, Luye Sun, Yuanqi Ding, Mengxi Liu, Lei Xie, Yinfu Liu, Lina Shang, Yangfan Wu, Hui-Jun Jiang, Lifeng Chi, Xiaohui Qiu, Wei Xu
Summary: This study focuses on the role of water molecules in driving chiral separation on the surface when RNA base uracil selfassembles into homochiral structures upon water exposure. The findings provide insights into the general role of water molecules in the origin of homochirality in living systems, with implications for other biologically relevant molecules such as amino acids and sugars.
Article
Chemistry, Physical
Lu Cao, Yang Song, Ya-Bin Liu, Qi Zheng, Guangyuan Han, Wenyao Liu, Meng Li, Hui Chen, Yuqing Xing, Guang-Han Cao, Hong Ding, Xiao Lin, Shixuan Du, Yu-Yang Zhang, Geng Li, Ziqiang Wang, Hong-Jun Gao
Summary: CaKFe4As4, a new type of iron-based superconductor, shows promise as a platform for observing Majorana zero modes. Using scanning tunneling microscopy/spectroscopy, two types of surface structures were identified, providing insight for future studies on the surface of iron-pnictide superconductors.
Article
Chemistry, Physical
Liangguang Jia, Fei Gao, Yu Zhang, Yaoyao Chen, Baofei Hou, Zeping Huang, Quanzhen Zhang, Xu Wu, Liwei Liu, Shiwu Gao, Mads Brandbyge, Hong-Jun Gao, Yeliang Wang
Summary: This study reports the influence of defects in vdW crystals on the local atomic configurations and interlayer coupling. The findings show that Se vacancies in few-layer NbSe2 can cause atomic distortions and generate in-gap states in single-layer NbSe2. Moreover, these vacancies lead to a significant suppression of interlayer coupling in the bilayer system.
Article
Materials Science, Multidisciplinary
Yongman Kim, Joong Il Jake Choi, Yongchan Jeong, Young Jae Kim, Jeong Young Park
Summary: This paper presents the design and performances of a beetle-type electrochemical scanning tunneling microscope (EC-STM) that allows horizontal tip motion at a millimeter range. The symmetrical scanner design of the beetle-type EC-STM reduces thermal drift and enables operation in various chemical reactions. Atom-resolved high-resolution scanning tunneling microscope images of highly oriented pyrolytic graphite (HOPG) and Au(111) surfaces in the liquid phase demonstrate the scan performance of the beetle-type EC-STM, which also provides real-time information on the electrode surface during electrochemical reactions.
CURRENT APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Solomon Amsalu Chekol, Stephan Menzel, Rana Walied Ahmad, Rainer Waser, Susanne Hoffmann-Eifert
Summary: The study investigates the switching dynamics of diffusive memristors based on volatile electrochemical metallization (v-ECM) devices, identifying the importance of filament formation and growth process on its relaxation time through analysis of threshold kinetics and filament relaxation.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Shaochuan Chen, Ilia Valov
Summary: Redox-based resistive random access memories (ReRAMs) rely on electrochemical processes involving oxidation and reduction within devices. Material selection plays a crucial role in resistive switching properties. The study explores the impact of materials configuration on redox reactions in HfO2-based ECM and VCM systems, highlighting the influence of capping layer materials and electrode configuration on resistive switching characteristics.
ADVANCED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
S. Tappertzhofen, L. Nielen, I Valov, R. Waser
Summary: The memristively programmable transistor design overcomes the tradeoff between long state retention and fast programming speed by using ions for programming, allowing for higher leakage current levels in gate-dielectrics. Experimental validation demonstrates the potential for high programming endurance and retention times, fast programming speeds, and high scalability.
Article
Engineering, Electrical & Electronic
G. Milano, L. Boarino, I Valov, C. Ricciardi
Summary: This research reports on the fabrication and characterization of memristive devices based on ZnO nanowires. Single crystalline ZnO nanowires were synthesized by a bottom-up approach and were utilized to create electrochemical metallization memory cells. These single crystalline devices not only serve as building blocks for nanowire-based memristive and neuromorphic systems, but also provide a model system for studying the physicochemical processes underlying memristive functionalities.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Deok-Yong Cho, Ki-jeong Kim, Kug-Seung Lee, Michael Lubben, Shaochuan Chen, Ilia Valov
Summary: Thin layers inserted between a metal electrode and a solid electrolyte can modify the transport of mass and charge at interfaces and affect electrode reactions. Incorporating C films in functional materials can alter the host's chemical properties and device functionalities. Using X-ray spectroscopies, it was found that inserting graphene or ultrathin amorphous C layers in a Ta2O5/Ta system can tune its chemical and electronic structures, thereby fundamentally changing the resistive switching functionalities.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Review
Chemistry, Multidisciplinary
Shaochuan Chen, Teng Zhang, Stefan Tappertzhofen, Yuchao Yang, Ilia Valov
Summary: Artificial neurons and synapses are crucial for the development of brain-inspired computing beyond von Neumann architectures. This article discusses the electrochemical fundamentals shared by biological and artificial cells, particularly their similarities with redox-based memristive devices. The driving forces and methods for controlling the functionalities through an electrochemical-materials approach are presented. Essential factors in understanding and designing artificial neurons and synapses, such as electrode symmetry, doping of solid electrolytes, concentration gradients, and excess surface energy, are discussed. Various memristive devices and architectures are showcased, along with their applications in problem-solving. The article provides an overview of neural signal generation and transmission in biological and artificial cells and highlights the potential for bioelectronic interfaces and integration of artificial circuits in biological systems. Prospects and challenges for low-power, high-information-density circuits are emphasized.
ADVANCED MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Min-Kyu Song, Ji-Hoon Kang, Xinyuan Zhang, Wonjae Ji, Alon Ascoli, Ioannis Messaris, Ahmet Samil Demirkol, Bowei Dong, Samarth Aggarwal, Weier Wan, Seok-Man Hong, Suma George Cardwell, Irem Boybat, Jae-sun Seo, Jang-Sik Lee, Mario Lanza, Hanwool Yeon, Murat Onen, Ju Li, Bilge Yildiz, Jesus A. del Alamo, Seyoung Kim, Shinhyun Choi, Gianluca Milano, Carlo Ricciardi, Lambert Alff, Yang Chai, Zhongrui Wang, Harish Bhaskaran, Mark C. Hersam, Dmitri Strukov, H. -S. Philip Wong, Ilia Valov, Bin Gao, Huaqiang Wu, Ronald Tetzlaff, Abu Sebastian, Wei Lu, Leon Chua, J. Joshua Yang, Jeehwan Kim
Summary: Memristive technology, with oxide-based resistive switches as memristors, has gained significant attention due to its biomimetic memory properties and potential improvement in power consumption. This review provides a comprehensive overview of recent advances in memristive technology, including devices, theory, algorithms, architectures, and systems. It also discusses research directions for applications in AI hardware accelerators, in-sensor computing, and probabilistic computing. Furthermore, it offers a forward-looking perspective, outlining challenges and opportunities for further research and innovation in this field.
Article
Nanoscience & Nanotechnology
Tumesh Kumar Sahu, Nishant Kumar, Sumit Chahal, Rajkumar Jana, Sumana Paul, Moumita Mukherjee, Amir H. Tavabi, Ayan Datta, Rafal E. Dunin-Borkowski, Ilia Valov, Alpana Nayak, Prashant Kumar
Summary: Researchers have discovered a new two-dimensional material called molybdenene, which has metallic character and can be hybridized with other materials to exhibit tunable optical and electronic properties. The study also demonstrates the applications of molybdenene in molecular sensing, electron imaging, and scanning probe microscopy.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Giuseppe Leonetti, Matteo Fretto, Fabrizio Candido Pirri, Natascia De Leo, Ilia Valov, Gianluca Milano
Summary: This study analyzes the effect of electrode metals on the resistive switching functionalities of NbOx-based memristive cells. The results show that the electronic blocking character of Schottky interfaces provided by Au and Pt metal electrodes results in better resistive switching performances. Furthermore, Pt is the best choice for realizing memristive cells with low variability in operating voltages, resistance states, and device-to-device variability when reducing the NbOx thickness.
SCIENTIFIC REPORTS
(2023)
Article
Nanoscience & Nanotechnology
Stephan Aussen, Felix Cueppers, Carsten Funck, Janghyun Jo, Stephan Werner, Christoph Pratsch, Stephan Menzel, Regina Dittmann, Rafal Dunin-Borkowski, Rainer Waser, Susanne Hoffmann-Eifert
Summary: In this study, two different switching modes of memristive devices with valence change mechanism were identified: filamentary mode and interfacial mode. The filamentary mode involves Joule heating, while the interfacial mode operates by modulating the accumulation and depletion of oxygen vacancies.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
Giuseppe Leonetti, Matteo Fretto, Katarzyna Bejtka, Elena Sonia Olivetti, Fabrizio Candido Pirri, Natascia De Leo, Ilia Valov, Gianluca Milano
Summary: This study provides a detailed analysis of the resistive switching properties of amorphous NbOx grown by anodic oxidation. The role of metal-metal oxide interfaces in regulating electronic and ionic transport mechanisms in Nb/NbOx/Au resistive switching cells is discussed. It is found that the resistive switching is related to the formation/rupture of conductive nanofilaments in the NbOx layer, facilitated by the presence of an oxygen scavenger layer at the Nb/NbOx interface. The electrical characterization shows durability, retention, and multilevel capabilities. The observation of quantized conductance supports the physical mechanism of atomic-scale conductive filaments formation.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Computer Science, Information Systems
Nils Kopperberg, Stefan Wiefels, Karl Hofmann, Jan Otterstedt, Dirk J. Wouters, Rainer Waser, Stephan Menzel
Summary: In this work, the endurance of 2 Mbit resistive switching random access memories (ReRAMs) from a 16 MBit test-chip is experimentally characterized. Rare failure events where the memory cells become stuck in the low-resistive state (LRS) are observed. Investigations, both experimental and simulation-based, are conducted to understand the underlying mechanisms causing the failure and provide suggestions for improving switching algorithms.
Article
Engineering, Electrical & Electronic
Christopher Bengel, Johannes Mohr, Stefan Wiefels, Abhairaj Singh, Anteneh Gebregiorgis, Rajendra Bishnoi, Said Hamdioui, Rainer Waser, Dirk Wouters, Stephan Menzel
Summary: This study investigates the impact of device and circuit-level effects on VMM in VCM crossbars, highlighting the importance of variability in the low resistive state and the preference for reading in the RESET direction.
NEUROMORPHIC COMPUTING AND ENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
Dennis Christensen, Regina Dittmann, Bernabe Linares-Barranco, Abu Sebastian, Manuel Le Gallo, Andrea Redaelli, Stefan Slesazeck, Thomas Mikolajick, Sabina Spiga, Stephan Menzel, Ilia Valov, Gianluca Milano, Carlo Ricciardi, Shi-Jun Liang, Feng Miao, Mario Lanza, Tyler J. Quill, Scott T. Keene, Alberto Salleo, Julie Grollier, Danijela Markovic, Alice Mizrahi, Peng Yao, J. Joshua Yang, Giacomo Indiveri, John Paul Strachan, Suman Datta, Elisa Vianello, Alexandre Valentian, Johannes Feldmann, Xuan Li, Wolfram H. P. Pernice, Harish Bhaskaran, Steve Furber, Emre Neftci, Franz Scherr, Wolfgang Maass, Srikanth Ramaswamy, Jonathan Tapson, Priyadarshini Panda, Youngeun Kim, Gouhei Tanaka, Simon Thorpe, Chiara Bartolozzi, Thomas A. Cleland, Christoph Posch, Shihchii Liu, Gabriella Panuccio, Mufti Mahmud, Arnab Neelim Mazumder, Morteza Hosseini, Tinoosh Mohsenin, Elisa Donati, Silvia Tolu, Roberto Galeazzi, Martin Ejsing Christensen, Sune Holm, Daniele Ielmini, N. Pryds
Summary: This article introduces the characteristics and advantages of von Neumann architecture and neuromorphic computing systems. While traditional von Neumann architecture is powerful, it has high power consumption and cannot handle complex data. Neuromorphic computing systems, inspired by biological concepts, can achieve lower power consumption for storing and processing large amounts of digital information. The aim of this article is to provide perspectives on the current state and future challenges in the field of neuromorphic technology, and to provide a concise yet comprehensive introduction and future outlook for readers.
NEUROMORPHIC COMPUTING AND ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Niloufar Raeis-Hosseini, Shaochuan Chen, Christos Papavassiliou, Ilia Valov
Summary: In this study, electrochemical metallization memory (ECM) devices were fabricated using sub-stoichiometric deposition of tantalum oxide films. The influence of zirconium as the active top electrode material was investigated in these devices. The results showed stable bipolar resistive switching properties, indicating that zirconium can be considered as a potential active electrode material for future nonvolatile nanoelectronics.