Article
Chemistry, Multidisciplinary
Kai-Huang Chen, Chien-Min Cheng, Mei-Li Chen, Yi-Yun Pan
Summary: This study investigated the bipolar switching properties and electrical conduction behaviors of ITO thin film RRAM devices. Transparent RRAM devices with ITO thin films were deposited on ITO/glass substrates using the RF magnetron sputtering method. The experimental results showed that all transparent RRAM devices exhibited a significant memory window and low set voltage for switching cycles of 120. The electrical transport mechanisms were determined to be dominated by the ohmic contact and space charge limit conduction models for set and reset states. Furthermore, the transmittance properties of the transparent ITO/ITOX/ITO RRAM devices were found to be approximately 90% for the visible wavelength range according to UV-Vis spectrophotometer measurements.
Article
Chemistry, Multidisciplinary
Kai-Huang Chen, Chien-Min Cheng, Na-Fu Wang, Ming-Cheng Kao
Summary: This study investigates and discusses the activation energy, bipolar resistance switching behavior, and electrical conduction transport properties of ITOX:SiO2 thin film resistive random access memory (RRAM) devices. The ITOX:SiO2 thin films were prepared using co-sputtering deposition on TiN/Si substrate. The RRAM device structure consisted of an Al/ITOX:SiO2/TiN/Si configuration, with aluminum as the top electrode and TiN as the bottom electrode. The study also examines the grain growth, defect reduction, and RRAM device performance of ITOX:SiO2 thin film under various oxygen gas flow conditions.
Article
Chemistry, Multidisciplinary
Kim Kuntze, Jani Viljakka, Matti Virkki, Chung-Yang (Dennis) Huang, Stefan Hecht, Arri Priimagi
Summary: By simple synthetic derivatisation, indigo dye can be converted into a red-light E-Z photoswitch, which exhibits negative photochromism and tuneable thermal isomerisation kinetics. This makes indigo derivatives highly attractive for materials and living systems applications. However, the translation of indigo photoswitching dynamics from solution to solid state, which is crucial for most applications, is not well understood. In this study, the photoswitching performance of six structurally distinct indigo derivatives in five polymers of varying rigidity is investigated. Three key strategies are identified to enable efficient photoswitching under red light: choosing a soft polymer matrix, creating free volume around the indigo molecules, and applying low dye loading to inhibit aggregation. Implementation of these strategies leads to isomerisation performance nearly identical to that in solution, paving the way for designing new red-light photochromic materials based on indigos.
Article
Engineering, Electrical & Electronic
Patrick Girard, Yuanqing Cheng, Arnaud Virazel, Weisheng Zhao, Rajendra Bishnoi, Mehdi B. Tahoori
Summary: Memories are a significant part of system-on-chips and contribute to the system power consumption. This article discusses the potential of magnetic random access memories to mitigate Flash shortcomings and be used as replacements for DRAM and SRAM. It provides an up-to-date coverage of MRAM test and reliability solutions in the literature, focusing on defectiveness and reliability issues.
PROCEEDINGS OF THE IEEE
(2021)
Article
Materials Science, Ceramics
Yoonho Ahn, Jong Yeog Son
Summary: In this study, RRAM devices with an oxygen-deficient layer were characterized, which showed significantly reduced forming and SET/RESET voltages compared to those without the oxygen-deficient layer. This reduction in voltages lowers the energy required to form conducting filaments, and the relatively high oxygen vacancy density in the oxygen-deficient layer leads to reduced dispersion in the forming and SET/RESET voltages.
CERAMICS INTERNATIONAL
(2021)
Article
Nanoscience & Nanotechnology
Min Ju Kim, Alba Martinez, Jaejoong Jeong, Seongho Kim, Wan Sik Hwang, Byung Jin Cho
Summary: This study proposes hybrid (H-) ReRAM devices using ultra-thin hybrid films prepared via initiated chemical vapor deposition (iCVD), and demonstrates their reliable performance under various temperature conditions. The unique composition of the conducting filament in these devices makes them potential candidates for alternative memory devices as well as neuromorphic and cognitive computing devices.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Physics, Applied
Takahide Kubota, Keita Ito, Rie Y. Umetsu, Koki Takanashi
Summary: This study investigated the potential application of a new material (Mn-Cr)AlGe in MRAMs, finding that it exhibits comparable or even higher perpendicular magnetic anisotropy energy at nanometer thicknesses compared to conventional materials, despite having lower saturation magnetization.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Qiang Huo, Yiming Yang, Yiming Wang, Dengyun Lei, Xiangqu Fu, Qirui Ren, Xiaoxin Xu, Qing Luo, Guozhong Xing, Chengying Chen, Xin Si, Hao Wu, Yiyang Yuan, Qiang Li, Xiaoran Li, Xinghua Wang, Meng-Fan Chang, Feng Zhang, Ming Liu
Summary: Three-dimensional computing-in-memory circuits based on vertical resistive random-access memory and complementary metal-oxide-semiconductor technologies can provide efficient hardware for artificial neural networks. Non-volatile computing-in-memory macros based on two-dimensional arrays of memristors are useful for the development of AI edge devices. The reported macro offers high energy efficiency for 3D vector-matrix multiplication operations and improves accuracy in brain MRI edge detection and CIFAR-10 dataset inference compared to conventional methods.
NATURE ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Lu Wang, Yukai Zhang, Dianzhong Wen
Summary: The study fabricates a flexible bioresistive memory using natural biological material, tussah hemolymph, exhibiting bipolar resistive switching and write-once-read-many-times characteristics, with good endurance and consistent electrical properties. This memory device can be applied for AND and OR logic operations in programmable logic circuits.
Article
Multidisciplinary Sciences
Zengguang Cheng, Tara Milne, Patrick Salter, Judy S. Kim, Samuel Humphrey, Martin Booth, Harish Bhaskaran
Summary: The research demonstrates the potential of using nanometer-scale metals to enhance light-matter interactions, with antimony as a pure metal capable of optically programmable transitions between two states. Its application prospects lie in optoelectronic modulation and switching speed, showcasing the simplicity and potential for various optoelectronic applications requiring actively tunable metallic conductors.
Article
Automation & Control Systems
Qiang Yi, Fei Yang, Weibin Zhuang, Yifei Wu, Yi Wu, Mingzhe Rong
Summary: Integrated gate-commutated thyristor (IGCT) is proposed as an alternative to achieve fault current clearance in hybrid dc breaker (HDCB) systems. However, parallel IGCTs lack intensive study on transient current balancing and optimization methods. This article presents a practical solution to achieve transient current balancing of parallel IGCTs in HDCB systems, and validates its feasibility through experiments.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Multidisciplinary Sciences
Tanmoy Maity, Pratibha Malik, Sumit Bawari, Soumya Ghosh, Jagannath Mondal, Ritesh Haldar
Summary: In heterogeneous porous systems, diffusion rate is influenced by pore window sizes and concentration gradient. This study demonstrates that, in a porous metal-organic framework system, diffusion can occur orthogonal to the concentration gradient. This finding reveals the complexity of diffusion in heterogeneous porous materials and provides insights for optimizing their design.
NATURE COMMUNICATIONS
(2023)
Review
Materials Science, Multidisciplinary
Se Eun Kim, Ju Young Sung, Jae Deock Jeon, Seo Young Jang, Hye Min Lee, Sang Mo Moon, Jun Goo Kang, Han Jin Lim, Hyung-Suk Jung, Sang Woon Lee
Summary: This article summarizes the recent advances in achieving sufficient capacitance in DRAM capacitors from structural and material/process perspectives. It also discusses the future direction of DRAM capacitor development, with a focus on the use of atomic layer deposition (ALD) technique for growing high-k and electrode thin films.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Nanoscience & Nanotechnology
Sanchari Dasgupta, Subharanjan Biswas, Kevin Dedecker, Eddy Dumas, Nicolas Menguy, Bruno Berini, Bertrand Lavedrine, Christian Serre, Cedric Boissiere, Nathalie Steunou
Summary: The design of efficient adsorbents for selective capture of volatile organic compounds (VOCs) is a global concern that affects air quality and preservation of cultural heritage. Metal-organic frameworks (MOFs) thin films, particularly UiO-66(Zr)-2CF3, show promising results in terms of high adsorption selectivity and stability for the capture of acetic acid (AA) in humid conditions similar to those found in museums.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Qiaoling Tian, Xiaoning Zhao, Ya Lin, Zhongqiang Wang, Ye Tao, Haiyang Xu, Yichun Liu
Summary: In this paper, a complementary resistive switch (CRS) with good thermal stability and low ON current is reported. The device consists of a bilayer structure made of amorphous carbon and thermally annealed copper-doped amorphous carbon. The presence of copper atoms in the amorphous carbon layer allows for the formation of nanosized active electrodes, enabling the migration and redistribution of copper species to form conductive filaments. The device operates stably at high temperatures and exhibits a low ON state current, showing potential for low power memory/computing applications and harsh electronics.
APPLIED PHYSICS LETTERS
(2022)
Review
Chemistry, Physical
Ritesh Haldar, Christof Woell
Summary: Functional, porous metal-organic frameworks (MOFs) are a flexible and diverse class of crystalline, porous materials that have attracted attention for advanced applications. Hierarchical assemblies and creation of MOF/MOF heterointerfaces are important for exploiting photophysical properties. Layer-by-layer (lbl) methods offer advantages in manufacturing superstructures with length scales beyond the MOF pore size, allowing for extended isoreticular approach and compositional diversity in MOFs.
Article
Chemistry, Multidisciplinary
Stefan M. Marschner, Ritesh Haldar, Olaf Fuhr, Christof Woell, Stefan Braese
Summary: This study reported the successful synthesis of a series of 5,15-bis(4-ethoxycarbonylphenyl)porphyrin derivatives through Suzuki and Sonogashira cross-coupling reactions, fully characterized and systematically investigated for their suitability in synthesizing surface-anchored MOF thin films.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Review
Chemistry, Multidisciplinary
Ralph Freund, Stefano Canossa, Seth M. Cohen, Wei Yan, Hexiang Deng, Vincent Guillerm, Mohamed Eddaoudi, David G. Madden, David Fairen-Jimenez, Hao Lyu, Lauren K. Macreadie, Zhe Ji, Yuanyuan Zhang, Bo Wang, Frederik Haase, Christof Woell, Orysia Zaremba, Jacopo Andreo, Stefan Wuttke, Christian S. Diercks
Summary: The core of reticular chemistry has brought precision and expertise of organic and inorganic synthesis to the solid state. The most profound scientific innovation of this field has been the design strategies for the synthesis of extended crystalline solids through strong directional bonds, highlighting the different classes of reticular materials developed and how complexity can be introduced into their backbones. Structural control over these materials is being extended from the molecular scale to their crystal morphology and shape on the nanoscale, all the way to their shaping on the bulk scale.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ritesh Haldar, Hongye Chen, Antoine Mazel, Dong-Hui Chen, Gaurav Gupta, Navneet Dua, Stephane Diring, Fabrice Odobel, Christof Woll
Summary: Efforts to achieve efficient high-yield wavelength conversion by stacking layers of chromophores have been unsuccessful so far. However, a significant improvement in optical conversion efficiency has been achieved through the use of chromophoric metal-organic framework heterolayers and an antenna doping strategy. The LR-FRET mechanism, previously reported to be highly anisotropic in neat materials, can be made more isotropic through doping strategies in optimized fabrication parameters.
ADVANCED MATERIALS INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Yi-Bo Tian, Nina Vankova, Peter Weidler, Agnieszka Kuc, Thomas Heine, Christof Woll, Zhi-Gang Gu, Jian Zhang
Summary: This research demonstrates the assembly of chromophores into well-ordered 1D arrays using MOF approach, resulting in highly sensitive photodetectors. The oriented MOF thin film-based high-sensitive photodetector shows potential for assembling organic semiconductors into regular arrays, creating a new avenue for optoelectronic device fabrication.
Article
Biochemistry & Molecular Biology
Tawheed Hashem, Elvia P. Valadez Sanchez, Evgenia Bogdanova, Anna Ugodchikova, Alaa Mohamed, Matthias Schwotzer, Mohamed H. Alkordi, Christof Woell
Summary: Metal-organic frameworks (MOFs) are intensively explored for novel applications and as alternatives to existing materials in thin film nanotechnologies. The stability of SURMOFs in harsh aqueous environments varies, with UiO-66-NH2 SURMOFs showing stability over a large window of pH values.
Article
Chemistry, Multidisciplinary
Sandeep Kumar, Yohanes Pramudya, Kai Mueller, Abhinav Chandresh, Simone Dehm, Shahriar Heidrich, Artem Fediai, Devang Parmar, Delwin Perera, Manuel Rommel, Lars Heinke, Wolfgang Wenzel, Christof Woll, Ralph Krupke
Summary: Graphene is inherently sensitive to vicinal dielectrics and local charge distributions, and can be used as a sensor; metal-organic frameworks can selectively adsorb specific molecular species; growing a surface-mounted metal-organic framework directly onto graphene field-effect transistors demonstrates a selective ethanol sensor with unprecedented shifts in Dirac point voltage response.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Alexei Nefedov, Ritesh Haldar, Zhiyun Xu, Hannes Kuehner, Dennis Hofmann, David Goll, Benedikt Sapotta, Stefan Hecht, Marjan Krstic, Carsten Rockstuhl, Wolfgang Wenzel, Stefan Brase, Petra Tegeder, Egbert Zojer, Christof Woell
Summary: The liquid-phase, quasi-epitaxial growth method is used to stack asymmetric organic compounds on inorganic substrates to create porous crystalline molecular materials without inversion symmetry, allowing for the integration of built-in electric fields. A new programmed assembly strategy based on metal-organic frameworks (MOFs) is described to facilitate the formation of crystalline, noncentrosymmetric space groups for achiral compounds. Integration of built-in electric fields into organic, crystalline, and porous materials offers possibilities for band structure engineering and tuning charge transfer for applications in organic electronics, photonics, and nonlinear optics.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Shujin Hou, Weijin Li, Sebastian Watzele, Regina M. Kluge, Song Xue, Shanshan Yin, Xinyu Jiang, Markus Doeblinger, Alexander Welle, Batyr Garlyyev, Max Koch, Peter Mueller-Buschbaum, Christof Woell, Aliaksandr S. Bandarenka, Roland A. Fischer
Summary: Materials derived from surface-mounted metal-organic frameworks (SURMOFs) show promising electrocatalytic performance for the oxygen evolution reaction (OER), with record-high electrocatalyst mass activities. The in situ self-reconstruction and self-activation of SURMOFs in alkaline aqueous electrolytes allow for the generation of NiFe (oxy)hydroxide electrocatalyst materials with specific morphology and microstructure.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Luiz G. S. Albano, Davi H. S. de Camargo, Gabriel R. Schleder, Samantha G. Deeke, Tatiana P. Vello, Leirson D. Palermo, Catia C. Correa, Adalberto Fazzio, Christof Woell, Carlos C. B. Bufon
Summary: The advances in surface-supported metal-organic framework (SURMOF) thin-film synthesis have enabled effective integration of MOF structures into electronic devices, leading to the observation of room-temperature negative differential resistance (NDR) in vertical heterojunctions. The NDR effect can be tailored by controlling humidity and electric field, resulting in high PVCR values under low voltages. These findings showcase the potential of utilizing physical effects in SURMOF heterojunctions for future scalable functional devices.
Article
Chemistry, Analytical
Benedikt Sapotta, Matthias Schwotzer, Christof Woell, Matthias Franzreb
Summary: This novel method combines electrochemical impedance spectroscopy with dielectrometry, providing a reliable way to determine thickness and permittivity values of thin films. It demonstrates the ability to monitor the in-situ growth of crystalline films on an interdigitated electrode geometry.
Correction
Physics, Multidisciplinary
Pablo G. Lustemberg, Philipp Plessow, Yuemin Wang, Chengwu Yang, Alexei Nefedov, Felix Studt, Christof Woll, M. Veronica Ganduglia-Pirovano
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Zeinab Mohammed Hassan, Peter G. Weidler, Alexei Nefedov, Yi Luo, Stefan Heissler, Manuel Tsotsalas, Ritesh Haldar, Christof Woell
Summary: Metal-organic frameworks (MOFs) with periodic and modular structures can predict the physical and chemical properties of organic chromophores. In this study, a zinc-bianthryl (Zn-BA) surface-anchored MOF (SURMOF) thin film was constructed using a BA chromophore with metal-coordinating carboxylate groups. It was found that a photoinduced topotactic transformation occurred in the presence of oxygen, leading to changes in the optical properties of the Zn-BA SURMOF.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Physical
Chengwu Yang, Yunjun Cao, Philipp N. Plessow, Jia Wang, Alexei Nefedov, Stefan Heissler, Felix Studt, Yuemin Wang, Hicham Idriss, Thomas G. Mayerhoefer, Christof Woell
Summary: Catalytic decomposition of N2O on macroscopic monocrystalline CeO2(111) surfaces has been studied and found to be an effective way to control N2O emissions. The higher activity of reduced ceria surfaces compared to oxidized surfaces has been confirmed through experiments.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Tahereh Mohammadi Hafshejani, Weijia Wang, Jonas Heggemann, Alexei Nefedov, Stefan Heissler, Yuemin Wang, Philipp Rahe, Peter Thissen, Christof Woell
Summary: Detailed information on the structural, chemical, and physical properties of natural cleaved (10.4) calcite surfaces was obtained through a combined AFM and IR study using CO as a probe molecule under UHV conditions. The study revealed the adsorption characteristics and vibrational frequencies of CO on the surface, with a well-defined adsorption site and clear vibrational bands.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)